Vol. 15, No. 4 July/August 1991
0145-6008/91/1504-0612$3.00/0
ALCOHOLISM: CLINICAL AND EXPERIMENTAL RESEARCH
Effects of Alcoholism and Instructional Conditions on Speed/Accuracy Tradeoffs Susan W. Glenn and Oscar A. Parsons
The speed and accuracy of neuropsychological performance in alcoholics and nonalcoholics were assessed for each item within a four-test computerized battery. Subjects were randomly assigned to one of three instructional conditions: Speed-emphasis instructions, Accuracy-emphasis instructions, or Typical instructions emphasizing speed and accuracy equally. Across conditions, alcoholics were less accurate and took longer to perform than controls. Examining speed and accuracy components separately within each condition, as predicted, the greatest differences in accuracy scores between alcoholics and controls appeared in the Speed-emphasiscondition, while the greatest group differences in speed scores appeared in the Accuracy-emphasis condition. The results indicate that the relationships between speed and accuracy are dissimilar betweenalcoholics and controls; alcoholics exhibit speed/accuracy tradeoffs in that they are unable to adjust performance to meet speed or accuracy demands without suffering substantial compromise in the other aspect of performance. These results have implications for future studies concerning methodological approaches to speed and accuracy assessment and provide support for an information-processing deficit associated with chronic alcohol abuse. Key Words: Female Alcoholics, Instructional Effects, Neuropsychological Performance, Speed/accuracyTradeoffs.
LCOHOLISM HAS BEEN associated with dysfunction A in a variety of psychomotor, cognitive and behavioral tasks.',' Two variables commonly assessed in many of these tasks are the speed and accuracy of performance. These variables can be addressed from several perspectives including: (1) measuring the variables independently in separate tasks and (2) measuring overall performance as the changing relationships between speed and accuracy under differing experimental conditions. The approach used to assess speed and accuracy determines to some extent the methodology as well as the conclusions or interpretations that can be made. This paper will address the issues of speed and accuracy assessment in alcoholics and controls using both of these approaches. From the Department of Psychiatry and Behavioral Sciences, Center for Alcohol and Drug Related Studies, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma. Received for publication June 21, 1990; accepted January 16, 1991 The research was supported, in part, by the National Institute dn Alcohol Abuse and Alcoholism grant lR01-AA06135 to Dr. Oscar A . Parsons. This research was conducted in partial fulfillment of the Doctor of Philosophy degree by the first author, under the direction of the second author, at the University of Oklahoma Health Sciences Center. Reprint requests: Susan W. Glenn, Ph.D., Department of Psychiatry, Center for Alcohol and Drug Related Studies, 800 N.E. 15th Street, Rogers Building, Suite 410, Oklahoma City, OK 73104. Copyright 0 1991 by The Research Society on Alcoholism. 612
SPEEDANDACCURACYASSEPARATEMEASURES Alcoholics have been found to be slower and more variable in their responses when compared with nonalcoholic controls on both simple and complex reaction tasks.'-' Alcoholics also demonstrate longer search times in visual discrimination tasks6 and take longer than controls for fine motor performance7and problem-solving tasks.' Accuracy, or the percentage of correct responses for a given task, also shows alcohol-related deficits over a wide range of functions. Alcoholics have been found to be less accurate than controls in discrimination of both visual and auditory ~ t i m u l i . ~They ~ ~ * are ' ~ also less accurate in psychomotor tasks such as visual-perceptual construction and in memory and location for tactual-spatial information." On other cognitive tasks such as general information,12digit encoding," immediate and delayed memory and new learning," and problem-solving and abstracting,14 alcoholics make significantly more errors or perform less accurately than comparison controls. These two aspects of performance, speed and accuracy, are often assessed independently of each other, as seen in the exclusion of incorrect responses in the calculation of mean reaction time," and in the employment of response deadlines or preset accuracy requirements.16 When accuracy and speed are allowed to vary freely and are assessed simultaneously, however, the relationships between the two aspects of performance and the methods by which the two are balanced may be examined.
SPEED AN ACCURACY RELATIONSHIPS There is some suggestion that alcohol, whether taken acutely or chronically, may adversely affect the ability to self-monitor behavior, e.g., to optimally vary the speed and accuracy of p e r f ~ r m a n c e . 'Porjesz ~.~~ and Begleiter'. lo examined the two variables using electrophysiological measures in an easy and difficult line-orientation discrimination task. Their results revealed that alcoholics manifested more time for stimulus evaluation and, unlike controls, did not respond differentially as a function of task difficulty. The authors concluded that alcoholics exhibited deficits in the rapid and accurate processing of information, and they were unable to adjust performance to meet both speed and accuracy demands without substantial compromise. York and Beiderman7gave alcoholics instructions to work as quickly and as accurately as possible on a target-tapping test. Their results indicated that alcoholics showed a speed/accuracy tradeoff relative to controls in that increases in speed compromised the accuracy of their performance. Taken together, the results of Pojesz and Begleiter'' and of York and Beiderman7 suggest that alcoholism may impair both the speed and accuracy of visual and motor performance relative to controls. In addition, the relationships between speed and accuracy may also be affected by alcoholism in that increases in one factor are achieved by decreases in the other, reflecting a tradeoff or compromise in the capacity to maintain one aspect of performance while responding to other task demands. The present study sought to extend these findings to tasks of cognitive performance.
EXPERIMENTAL HYPOTHESES The purpose of the present study was to assess the speed and accuracy of neuropsychologicalmeasures under three instructional conditions that Alcohol Clin Exp Rex, Vol 15, No 4, 1991: pp 612-619
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ALCOHOLISM EFFECTS ON SPEED/ACCURACY TRADEOFFS
vary in the emphasis placed on speed and accuracy: a condition emphasizing accuracy (0% errors) at the possible expense of speed (Accuracyemphasis condition), a condition emphasizing speed at the possible expense of accuracy (Speed-emphasis condition), and a condition emphasizing equal importance of both speed and accuracy (Typical-emphasis condition).’9The interrelationships between speed and accuracy measures were examined, and the two measures were examined as independent measures as well. It was expected that controls would demonstrate tradeoffs between performance factors in the various conditions such that speed instructions produce increases in speed with concomitant decreases in accuracy, and vice versa for accuracy instructions. It was hypothesized that alcoholic performance, however, would be characterized by such tradeoffs to a greater extent than controls. The following experimental hypotheses were tested:
Hypothesis I Alcoholics, compared with controls, will have lower accuracy scores and higher (take longer) speed scores on perceptual-cognitivetests.
Hypothesis 2 Alcoholics, compared with controls, will have greater trade-offs between speed and accuracy under different experimental conditions. Specifically, alcoholics (relative to controls) will show the greatest deficits in accuracy scores in the Speed-emphasis condition and will show the greatest deficits in speed scores in the Accuracy-emphasis condition.
METHOD Subjects The sample consisted of 48 female alcoholics recruited from alcoholism treatment centers in the Oklahoma City area, and 36 female nonalcoholic community controls. All alcoholic subjects had been diagnosed alcohol-dependent according to National Council on Alcoholism (NCA)” or DSM-111-R criteria” and had been detoxified for 3 to 6 weeks before testing. Subjects were excluded if screening interviews or medical charts revealed a history of neurological disease or trauma, major psychiatric disorder, acute medical problems such as cardiovascular or liver problems that could lead to central nervous system (CNS) dysfunction, or if they were currently receiving any psychoactive medication. All subjects were between 2 1 and 49 years of age, had at least an 8th grade education, and were of dull normal intelligence or higher as measured by the Shipley Vocabulary Scale?’ All subjects were administered the Beck Depression Inventory2’and the State Anxiety In~entory,’~ and they were given an interview concerning drinking and substance abuse experience. The interview data were used to construct a quantity-frequency index (QFI)” and the typical number of ounces drunk per drinking occasion. Alcoholics and controls were equated on relevant demographic variables and did not differ on the Beck or the State Anxiety Inventory (Table I). Informed consent documents were read and signed by each subject before testing and all received monetary compensation for their participation.
each task. These practice trials were not included in the mean reaction time or accuracy measures in the subsequent analyses, and the subjects were informed when the practice trials were completed and when the test trials began. Specific test measures are discussed below. Simple Reaction Time. This task required the subject to press a button each time a visual stimulus (a star) appeared on the computer screen. Three types of intertrial intervals (approximately 1, 2.5, and 5 sec) were presented in random order with a total of 75 trials. Only 60 of the 75 trials (20 of each of the three intertrial intervals) were included in the analyses; trials beyond the subject’s standard deviation range for that particular intertrial interval were not included. This task was included to assess whether any differences obtained on the cognitive tests could be attributed to a pervasive slowing of response to any stimulus. Visuospatial Orientation. This aspect of functioning was assessed by the “Little Men Test” (abbreviated LM)? The test required the subject to make right/left discriminations on a manikin which was rotated along two axes (up/down, front/back). The manikin, presented on the computer screen, held a briefcase in one hand; the objective was to determine which hand the case was in. Four practice trials were completed before the test began, allowing subjects to be familiarized with the four possible manikin positions. The subject then began the test and responded by pressing the “right” or the “left” key for each of the 32 test trials. VisualPerceptualSkills.The computerized Visual Perceptual Analysis (VPA)26required subjects to detect graduated differences in geometric patterns. Three five-by-four matrices were presented in each trial; the subject’s task was to identify the one matrix that differed from the other two. Four practice trials were given before the 24 test trials began. Problem-Solvingand Abstracting. This cognitive ability was assessed using the Bexley-Maudsley Category Sorting Test (BMCST),26a computerized version of the Wisconsin Card Sorting Test.” The test required subjects to use abstract concepts to develop sorting criteria and to modify these concepts to develop sorting criteria and to modify these concepts as the computer altered test solutions. The sorting criteria defined by the computer were the orientation of elements, number of elements, and the type of elements (rather than color, form, and number criteria used by the noncomputerized version of the test). Feedback concerning the accuracy of the subject’s response appeared on the screen following each sorting attempt. Six consecutivecorrect responsesconstituted a successful completion of one category; there were six categories to be sorted. Subjects did not receive practice problems on this test. Short-Term Memory. A version of the “Sternberg task”’’ was used to assess short-term memory. The subject was presented with a memory set of digits, ranging in set size from 1 to 6 digits. The digits were presented serially at the rate of l/sec. Immediately after presentation of the set, a signal was given (a plus sign) after which a probe digit was presented. The subject’s task was to indicate whether the probe digit was a member of the memory set. Following this “presence or absence” judgment, the subject was asked to recall the digits of the memory set. Twelve practice trials were given, and then the 48 experimental trials.
Procedure
As the subjects were participants in a larger study, the Efficiency Battery was administered in conjunction with several other assessment procedure^.^^ A battery of neuropsychological tests was administered in a morning testing session lasting approximately 2 to 3 hr. The subjects were given a lunch break, and then the Efficiency Battery was given, Materials followed by another break and an interview session concerning medical, All subjects were administered a simple reaction time task and a , social, and alcohol abuse histories. This testing order was the same for battery of tests that assessed those functions most frequently impaired in alcoholics and controls and was structured to maximize performance chronic alcoholism: problem-solving and abstracting, short-term mem- and reduce fatigue. The Efficiency Battery took approximately 1 hr to ory, visual-spatial skills, and perceptual analysis The tests complete and was administered by trained research assistants. All subjects were administered on an Apple I1 or I1 Plus computer, and both accuracy received the simple reaction time task first; the order of the remaining and speed were recorded for each test item. For each of the tests (except five tests was randomly preselected for each subject. Subjects were randomly assigned to one of the three experimental the Bexley-Maudsley Category Sorting Test,26for which practice trials were not available), several practice problems were administered before conditions, with 16 alcoholics and 12 controls in each. Before beginning the test began, allowing subjects to become familiar with the specifics of the battery, subjects were informed that this portion of the testing would
GLENN AND PARSONS
614
assess both speed and accuracy aspects of performance. They were told that in order to examine the ways in which speed and accuracy affected overall performance, we would be studying performance under three different conditions; the experimenter then described each of the three performance conditions (see descriptions below). The rationale for informing subjects of the three possible conditions (instead ofjust her own condition assignment) was to illustrate for the subject the contrast between conditions in order to assist her in interpreting her conditionspecific performance requirements. For example, subjects could more clearly appreciate the meaning of accuracy-emphasis conditions if they also understood that other subjects would be working under speedemphasis conditions, and still others working under both speed- and accuracy-emphasis conditions. This method of pretest instruction is thought to help anchor high and low points of performance on the speedoperating characteristic curve,3oand to help subjects respond in experimenter-rather than individually-defined capacities.” We have reported that while alcoholics and controls may not perform at similar levels on various cognitive tests, they do not differ in their motivation to attempt to perform in accordance with experimental demands3’;therefore, we did not anticipate any group-specific effect of the pretest instructions. Subjects were not informed of the experimental hypotheses, nor of any anticipated differences in groups’ performances. Before beginning each test within the battery, specific instructions were given regarding task requirements, and the appropriate speed or accuracy performance instructions were reiterated. The three experimental conditions are described below: Accuracy-Emphasis Condition. Instructions were given to perform each task “as accurately as possible, taking as much time as necessary in order to make as few mistakes as possible.” Speed-Emphasis Condition. Instructions were given to perform each task “as quickly as possible, keeping in mind that some errors are acceptable as long as the effort is made to work as rapidly as possible.” Typical-EmphasisCondition. Instructions were given to perform each task “as quickly and as accurately as possible.” (Sharps and Collin3*have shown that the order of instruction, to “perform as quickly and as accurately,” or as “accurately and quickly” have the same effect on test performance.) Speed and accuracy were recorded for each test item. For analyses the means of accuracy and reaction times were used to create summary accuracy and speed scores for each of the tests (excluding simple reaction time). These summary scores were then standardized to a mean of 50 k 10 ( T scores). The statistical analyses were completed using the SAS33 and BMDP34statistical packages within the university mainframe computing system. To examine differences between alcoholicsand controls on speed and accuracy measures, the first experimental hypothesis, multivariate analyses of variance (MANOVAs) were conducted for group (alcoholic versus control) and instructional condition effects on the speed and accuracy scores of the four computerized tests. To address the second experimental hypothesis, simple effects analyses of the speed and accuracy scores for alcoholics and controls within each instructional condition were conducted to examine group differences as a function of condition. (Because some differences between alcoholics and controls were expected in each of the three instructional conditions, it was felt that simple effectsanalyses could best assess Hypothesis 2 despite the lack of group x condition main effect interactions.) Demographic characteristicsof the sample were compared using Student’s t test.
Table 1. Means (+SO) for Demographic Characteristics
Age Years education Beck depression inventory State anxiety Years of alcohol abuse Quantity frequency index (QFI) Typical ounces of ethanol
Alcoholics
Controls
(n = 48)
(n = 36)
32.8 (k7.2) 12.3 (k2.0) 6.3 (k6.8) 48.9 (59.2) 10.4 (k7.0) 13.3 (k13.0) 16.6 (514.9)
32.6 (56.2) 13.0 (k1.2) 4.2 (k5.3) 46.2 (k7.9) 0.12 (k0.21) 0.79 (k0.97)
Table 2. Means ( ~ s D for ) Reaction Time (in msec)
Accuracy emphasis condition Alcoholics Interval 1.O’ Interval 2.5 Interval 5.0 Controls Interval 1 .O Interval 2.5 Interval 5.0
Typical emphasis condition
Speed emphasis condition
Mean
279.3 (59.4) 270.4 (61.O) 268.9(38.6) 273.1 (53.4) 251 .I (48.4) 273.4(41.2) 258.5(49.6) 260.8(46.5) 266.9(54.4) 286.2(55.7) 270.1(47.1) 274.3(52.3) 267.3(49.6) 255.6(47.3) 249.6(40.6) 257.2(45.1) 256.1 (40.7) 242.4 (28.7) 231.9(28.8) 243.1 (33.5) 262.4(33.5) 249.3 (26.0) 235.7(27.1) 248.8(30.1)
* Intervals refer to the three intertrial intervals in seconds.
provide descriptive information concerning chronicity as well as pattern of alcohol abuse. The means for the alcoholics’ consumption variables are typical of those reported in other ~ t u d i e s ,indicating ~ ~ , ~ ~ that the sample is representative of the female alcoholic population. There were no significant group, condition, or group X condition effects on age, education, or anxiety scores. For depression scores, there was a significant effect of condition [F(5,71) = 5.60, p < 0.011, but there were no significant group differences or group x condition interactions. Subsequent analyses covarying for depression levels demonstrated that performance differences between alcoholic groups, or between alcoholics and controls, could not be attributed to the depression differences. Finally, alcoholic groups did not differ on the duration of alcohol abuse [F(2,45) = 1.88, p > 0.151, QFI [F(2,45) = 0.71, p > 0.481, or the typical ounces of ethanol consumed per drinking occasion [F(2,45) = 0.53, p > 0.581.
Simple Reaction Time Means for the simple reaction time task can be seen in Table 2. Using a group X condition X intertrial interval repeated measures analysis, alcoholics were significantly RESULTS slower overall than controls on reaction time [F(1,77) = Demographic characteristics of the sample are given in 4.26, p c 0.0441. A significant main effect of intertrial Table 1. As can be seen, alcoholics did not differ signifi- interval was found, [F(2,76) = 10.22, p < 0.0011; there cantly from controls on demographic variables of age or were no significant main effects of condition, or any group educational level or on affective measures of state anxiety x condition or intertrial interval X condition interactions. and depressive syrnptomatoIogy. Also listed for the sub- Further examination of the intertrial interval effect using jects in Table 1 are consumption variables in order to simple effects analyses indicated that the differences be-
615
ALCOHOLISM EFFECTS ON SPEED/ACCURACY TRADEOFFS
tween alcoholics and controls became greater as the intertrial interval increased [for 1.O-sec intertrial interval, F(1,77) = 1.84, p > 0.178; for 2.5-sec intertrial interval, F(1,77) = 3.62, p > 0.060; for 5.0-sec intertrial interval, F(1,77) = 6.53, p > 0.0121. Concerning the relationships between reaction time and other performance measures, correlational analyses were conducted between mean reaction time and the speed and accuracy scores of each of the four computerized tests. Of the 16 possible correlations, (eight for alcoholics and eight for controls), only one correlation was significant (for controls, mean reaction time and Sternberg speed score, r(1,35) = 0.506, p < 0.002). Importantly, there were no significant correlations between alcoholics' reaction times and performance on the test battery, illustrating that alcoholic performance deficits could not be attributed to differences between the groups in simple reaction time.
Speed and Accuracy Components In Table 3 are the speed and accuracy T scores for each experimental cell and in Table 4 are the results of the separate analyses for speed and accuracy scores. Turning first to the speed scores, a significant multivariate main effect of group was seen as alcoholics combined across conditions were slower than controls overall, and on each of the four computerized tests. Combining alcoholics and controls, a significant multivariate main effect of condition was seen as the speed scores differed among the three conditions. Significant univariate effects of condition were found for each test except the Sternberg. Examination of the means indicated that the speed scores for alcoholics and controls in the Accuracy-emphasis condition were the slowest in each case. The speed scores for alcoholics and controls were not differentially affected by the instructional conditions, however, as there were no group X condition interactions. Examination of accuracy scores revealed a significant group main effect, demonstrating that alcoholics (combined across conditions) were less accurate overall than controls and had significantly lower accuracy scores on the LM, BMCST and Sternberg tests. Main effects of
condition were found as well, and accuracy scores were significantly different between the three instructional conditions in the overall multivariate analysis and showed significant univariate effects on two of the four computerized tests (LM and VPA). On these two tests the lowest accuracy scores of the three alcoholic groups and the three control groups were found in the Speed-emphasis condition. As in the analysis of speed scores, there were no group X condition interactions for accuracy scores. Examining alcoholics and controls for between-group differences within each instructional condition, comparison of alcoholicsand controls within the Accuracy-emphasis condition indicated that the two groups did not differ in accuracy scores (Table 5). However, alcoholics had significantly slower speed scores than controls both overall and on each of the four tests. In the Speed-emphasis condition alcoholics were also significantly slower than controls overall and on two of the individual tests (VPA and Sternberg). Comparing accuracy scores under Speedemphasis instructions, alcoholics were less accurate than controls overall and on the BMCST and Sternberg individual tests. Interestingly, in the Typical-emphasiscondition alcoholics did not differ from controls on speed or accuracy measures. To summarize these results, the greatest differences in accuracy scores between alcoholics and controls on the computerized tests appeared in the Speed-emphasis condition, with alcoholics in this condition performing less accurately than controls both overall and on two of the four individual tests. There were no significant differences between alcoholics and controls on accuracy scores in either the Accuracy-emphasis or the Typical-emphasis conditions. Conversely, the greatest differences in speed scores appeared in the the Accuracy-emphasis condition, in which alcoholics were slower than controls on all four of the tests. Overall group differences for speed scores were also found in the Speed-emphasis condition, with alcoholics differing from controls on two of the four tasks in this instructional condition. These results provide support for Hypothesis 2. In terms of tradeoffs between speed and accuracy, alcoholics generally appear to trade speed for
Table 3. T Scores (im) for Speed and Accuracy Dependent variables',t Controls Instructional condition
Alcoholics Instructional condition
~~
~
LM Accuracy LM Speed VPA Accuracy VPA Speed BMCST Accuracy BMCST Speed Sternberg Accuracy Sternberg Speed
-~
Accuracy emphasis
Typical emphasis
speed emphasis
Mean
Accuracy emphasis
Typical emphasis
speed emphasis
Mean
49.3 (10.1) 61.1 (13.9) 52.8 (4.5) 59.8 (14.1) 47.8 (11.1) 61.3 (16.1) 49.6 (10.8) 56.0 (9.4)
49.6 (10.1) 47.9 (8.0) 50.8 (6.6) 48.0 (5.5) 51.0 (10.1) 46.8 (2.8) 51.7 (7.8) 51.1 (10.7)
44.6 (9.2) 48.0 (8.4) 44.7 (14.8) 49.5 (8.4) 44.5 (12.3) 47.9 (5.8) 42.0 (13.7) 53.4 (10.9)
47.9 (10.1) 52.5 (12.0) 49.5 (9.9) 52.5 (11.2) 47.8 (11.2) 52.1 (11.9) 47.9 (11.5) 53.5 (10.3)
55.7 (6.9) 49.6 (5.4) 55.8 (1.3) 51.1 (8.1) 54.2 (6.5) 52.2 (6.8) 52.8 (7.8) 49.4 (9.0)
54.3 (9.7) 46.7 (3.9) 53.1 (5.2) 47.3 (3.5) 51.7(10.4) 46.4 (3.4) 51.4 (8.3) 45.8 (5.4)
48.2 (10.0) 44.1 (4.4) 43.0 (14.1) 41.9 (6.1) 52.6 (4.4) 43.2 (2.3) 53.2 (4.6) 40.9 (5.8)
52.7 (9.3) 46.8 (5.0) 50.6 (10.1) 46.8 (7.1) 52.8 (7.4) 47.3 (5.8) 52.5 (6.9) 45.4 (7.6)
~
~
* LM, Little men; VPA, visual perceptual analysis; BMCST, Bexley-Maudsley Category Sorting Test.
t T Scores were calculated on the basis of the combined distribution of alcoholics and controls. Note that the higher the T score the better the accuracy performance while the higher the T score for speed, the longer time taken to perform the task.
616
GLENN AND PARSONS
and controls in the Typical-emphasjscondition was somewhat surprising. However, there were no significant group Groupt Condition* x condition interactive effects for performance scores F P F P across the three conditions for either alcoholicsor controls, Speed multivariate 5.50 0.0006 4.47 0.0002 illustrating that the performances of alcoholics and conS p e d univariates trols in the Typical-emphasis condition were not greatly Little men 8.80 0.0040 9.70 0.0002 Visual-perceptual 8.79 0.0040 9.79 0.0002 different from the performances of their respective groups BMCST 6.76 0.0112 15.57 0.0001 in the other two conditions. Stemberg 16.50 0.0001 2.76 0.0696 The alcoholicsin the current study were relatively young Accuracy multivariate 2.56 0.0457 2.66 0.0094 (early 30s) compared with the typical age range of studies Accuracy univariates Little men 5.30 0.0241 3.39 0.0389 with male alcoholics (40s-60s). Several studies using 0.35 NSS 9.54 0.0002 Visual-perceptual younger male alcoholics of similar age as the current 5.45 0.0222 0.69 NS BMCST 4.98 0.0285 1.42 NS female subjects have reported equivocal findings with Stembera regard to cognitive deficits; some studies have found eviThere were no significant interactions involving the performance measures and conditions. dence of alcohol-related deficits while others have t Group multivariate (df = 4,74) for Speed and Accuracy analyses; group While there were no significant differences in age across univariate (df = 1.77). conditions, it is possible that the failure to find consistent *Condition multivariate (df = 8,148); condition univariate (df = 2,77). 5 NS, not significant. alcohol-related performance deficits across conditions in the present study is partially due to the age of the subjects, accuracy. That is, while alcoholics showed no impairment and the tendency to find inconsistent results when dealing in accuracy scores relative to controls in the Typical- or with younger alcoholics. Future replication studies may Accuracy-emphasis conditions, speed scores for alcoholics further explain the performance of subjects in the Typicalwere slower than controls for most of the tests in both the emphasis condition. Accuracy-emphasis and Speed-emphasis conditions. Table 4. Multivariateand Univariate Analyses Of Speed and Accuracy Scores (Main Effects)'
~~
Speed-AccuracyRelationships and Condition Efects DISCUSSION
Simple Reaction Time The alcoholics in the sample were significantly slower than controls on the simple reaction reaction time task, supporting results from other studies using male alcoholic^^,^ and extending the use of reaction time tasks to female alcoholic populations. The differences between alcoholics and controls in reaction time became greater as the amount of time in the intertrial interval increased, with the 5-sec interval of Trial Type Three providing the largest group differences. Because increases in intertrial intervals require greater sustained attention and concentration than the shorter intervals, it is possible that the attention deficit disorder symptoms common in alcoholic population^^^,^^ are instrumental in the manifestation of deficits on these types of tasks.
Alcoholic Deficits in Speed and Accuracy As demonstrated by the main effects (Table 4),alcoholics as a group were significantly less accurate and slower than controls on each of the tests within the battery, providing support for the first experimental hypothesis. The results of the performance differences in speed aGd accuracy scores between alcoholics and controls in the Speed-emphasis and Accuracy-emphasis conditions indicate that relationships between the speed and accuracy of performance were affected by instructional conditions as well as by alcoholism. The lack of significant differences between alcoholics
The relationships between speed and accuracy are best demonstrated using the speed-accuracy operating characteri~tic.~'This operating characteristic can be used to represent graphically the relationships between speed and accuracy across experimental conditions. These curves plot the average response latency against the mean accuracy of responses for each of the various conditions. Ideally, the Speed-emphasiscondition anchors the bottom portion of the curve where response time is fast and accuracy is low. The Accuracy-emphasis condition, on the other hand, represents the top portion of the curve where accuracy is high and response times are slow. The Typicalemphasis condition falls into the middle portion of the curve between the other two conditions. It was anticipated that in this study the performance of the controls would reflect this ideal operating characteristic. Figs. 1 and 2 (the LM and VPA tests) demonstrate the expected relationship between the controls in the three conditions and illustrate that the alcoholics' speed-accuracy operating characteristisc were shifted downward and to the right, reflecting large tradeoffs and apparent differences in basic speedaccuracy relationships between alcoholics and controls. For example, on these two tests controls were the most accurate and the slowest in the Accuracy-emphasis condition, and vice versa for the Speed-emphasis condition, and vice versa for the Speed-emphasis condition. Alcoholics, on the other hand, were equally or less accurate in the Accuracy-emphasiscondition than the Typical-emphasis condition, and were even slower in the Speed-emphasis condition than in the Typical-emphasis condition. The speed-accuracy curves for the BMCST and the
617
ALCOHOLISM EFFECTS ON SPEED/ACCURACY TRADEOFFS
Figure 1
Figure 2
Llttle Men
Vlsuoperceptual
60
62-
60-
58-
58
--
A
A
- - - - - - -0
-----
o - - - - - - - - - - - _ _ _ _ _ _ - - *
46-
I I
46U -
46-
u-
5 b
u-
u
40
Speed Scores
Speed Scores Alwhollcl
*
Alaohollas
Controls
Controls
Figure 4 Sternberg Aaauraq Saanr 6058
58-
56
-
A
46-
\
U 42-
5 0
0
:I Alwhollas
*
Coniralr
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44
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u
sb
Alooholkr
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Contmlr
Figs. 1-4.
Table 5. Simple Effects Analyses for Speed and Accuracy Scores: By Condition Accuracy emphasis condition
Typical emphasis condition
speed. emphasis condition
P
F
P
F
P
4.17
0.004
0.61
NSS
3.40
0.013
12.86 7.02 8.50 3.66
0.001 0.009 0.005 0.059
0.15 0.04 0.01 2.37
NS
NS
1.44 5.17 2.17 12.71
0.001
1.18
NS
0.49
NS
2.95
0.025
3.01 0.73 2.92
NS
NS
NS
0.92 0.24 4.60 9.25
NS
0.80
1.69 0.45 0.03 0.01
F Speed scores Multivariate' Univariatest LM VPA BMCST Sternberg Accuracy scores Multivariate. Univariatest LM VPA BMCST Stemberg
* Multivariate (df = 4,74). t Univariates (df = 1.77).
*
NS,
not significant.
NS NS
NS NS
NS NS NS
NS
0.026 NS
NS
0.035 0.003
Sternberg tests are presented in Figs. 3 and 4. Perhaps because these tests assess problem-solving and memory functions rather than choice visual discriminations, the speed-accuracy curves for the controls as well as alcoholics do not fit the ideal speed-accuracy operating characteristic. It is apparent for each of these speed-accuracy curves, however, that the relationships between speed and accuracy are dissimilar for alcoholics and controls, reflecting alcoholics' apparent difficulties when required to rapidly or accurately process information, and to adjust performance to meet speed or accuracy demands without substantial compromise in the other aspect of performance. These results may be construed as an extension of the findings seen in electrophysiological studies of chronic alcoholics. As the results of Porjesz and Begleiter','' have indicated, alcoholics demonstrate difficulties in distinguishing relevant from irrelevant stimuli. For example, in tasks utilizing target and nontarget stimuli, alcoholics' electrophysiological response is often similar to both types of targets while controls exhibit large responses to target
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stimuli and small responses to nontargets. Further studiesI8 suggest that the lack of response discrepancy between targets and nontargets reflects alcoholics’ tendencies toward uniform, rather than dynamic, adaptive responses to changing environmental stimuli. In the present study, the instructions in the Typiculemphasis condition represented the most common type of instructions seen in testing situations. Instructions were given to work “as quickly and as accurately as possible.” Because these Typical instructions were most like those given in other testing situations they may have been the most familiar and least difficult or stress-provoking type of instructions. Given these instructions, alcoholics were able to perform as well as controls. However, the instructions for the Speed- and Accuracy-emphasis conditions, less common in testing situations, require the subject to prioritize, or channel, efforts toward one aspect of their performance over the other. The results suggest that controls are able to channel efforts to meet specific performance demands, while at the same time maintaining adequate levels of performance in the nonspecified aspect. Alcoholics, on the other hand, are characterized by an inability to perform well under novel, nontypical instructions. That is, they are unable to cognitively “shift gears” from the usual mode of functioning to focus on only one aspect of their performance without suffering substantial compromise in the other aspect of performance to which they are not attending. This suggestion has potential implications for gaining a better understanding of the cognitive deficits associated with alcoholism and deserves further attention and replication.
available; (3) this study illustrates clearly that special consideration should be given to the instructional set provided at the beginning of any testing session. Significant condition effects were found for both alcoholics and controls, suggesting that both groups are sensitive to, and respond quite differently, when given instructions emphasizing speed or accuracy, or both; and (4) the failure of alcoholics to adequately manage either speed or accuracy components of performance suggests an information processing deficit sensitive to the presence of alcohol abuse. Perhaps it is this last point that offers the greatest relevance for day-to-day circumstances. Many situations in the everyday world call for the rapid or accurate evaluation of incoming information such as driving, assemblyproduction tasks, operation of heavy machinery, and even the successful completion of standardized education tests. In the United States alone, over $70,905 million are lost each year due to lost employment or decreased productivity caused by alcohol and 17,847 lives lost in alcohol-related traffic accidents,43 illustrating potential cases in which inadequate tradeoffs between speed and accuracy may have caused detrimental or even deadly consequences. Clearly, the further investigation of speedaccuracy relationships in alcoholics merits careful and thorough consideration. ACKNOWLEDGMENTS We appreciate the help of Cynthia Kelley, B.A., and Jatinder Singh, M.S., in administering the battery to the subjects. We also thank Sara Jo Nixon, Ph.D., for her constructive comments on this paper,
REFERENCES
Implications for Future Research The findings of the present study illustrate the deficits in speed-accuracy relationships in female alcoholics. Given the number of studies that have included only male alcoholics, there is a relative paucity of studies in the literature that examine alcohol’s effects on female cognitive functioning; this study provides an important contribution to that body of scientific knowledge. A limitation of the current study, however, is the inclusion of only female subjects, as there is some evidence in both acute alcohol administration and chronic alcohol abuse that speed and accuracy are affected differentially by gend e r . ” ~Further ~ ~ studies are needed to examine the role of gender in speed and accuracy relationships. The findings of this study also have several implications for future studies in both methodological and application areas: (1) measures of speed and accuracy can be assessed from several different perspectives; the particular approakh adopted influences the methodology and the nature of the conclusions that can be drawn; (2) the Efficiency Battery used in this study is primarily computerized and takes only an hour to administer, suggesting potential uses even in situations where the time or resources needed for a complete traditional neuropsychological battery are un-
1. Tarter R Brain damage in chronic alcoholics: A review of the psychologicalevidence, in Richter D (ed): Addiction and Brain Damage. London, Croom and Helm, LTD, 1980 2. Parsons OA: Alcoholics’neuropsychologicalimpairment: Current findings and conclusions. Ann Behav Med 8:13-19, 1986 3. Carpenter J: Effects of alcohol on some psychological processes: A critical review with reference to driving skill. Q J Stud Alcohol 23:274313, 1962 4. Talland G: Psychological studies of Korsakoffs psychosis: V. Spontaneity and activity rate. J Nerv Ment Dis 130:16-25, 1960 5. Talland G: Alcoholism and reaction time. Q J Stud Alcohol 24610-621, 1962 6. Bertera J, Parsons OA: Impaired visual search in alcoholics. Alcohol Clin Exp Res 2:9-14, 1978 7. York J, Beiderman I: Motor performance in detoxified alcoholics. Alcohol Clin Exp Res 12:119-124, 1988 8. Klisz D, Parsons OA: Hypothesis testing in young and older alcoholics. J Stud Alcohol 38: 1718- 1729, 1977 9. Pojesz B, Begleiter H: Event-relatedpotentials and decision time in chronic alcoholics. Paper presented at the International Council on Alcohol Abuse, Vienna, Austria, 1981 10. Pojesz B, Begleiter H: Event-related potentials in chronic alcoholics. Paper presented at the 134th Annual Meeting of the American Psychiatric Association, New Orleans, LA, 1981 11. Noonberg A, Goldstein G, Page H: Premature aging in male alcoholics: “Accelerated aging” or “Increased Vulnerability”? Alcohol Clin Exp Res 9:334-338, 1985 12. Tarter R Psychological deficit in chronic alcoholics: A review. Int J Addict 10:327-368, 1975
ALCOHOLISM EFFECTS ON SPEED/ACCURACY TRADEOFFS
619
28. Sternberg S: The discovery of processing stages: Extensions of 13. Schaeffer K, Parsons OA: Learning impairment in alcoholics using an ecologically relevant test. J Nerv Ment Dis 175:2 13-2 18, 1987 Donder’s method, Acta Psychol 30:276-3 IS, 1969 29. Glenn SW, Parsons O A Neuropsychological efficiency measures 14. Turner J, Parsons OA: Verbal and nonverbal abstracting-problem-solving abilities and familial alcoholism in female alcoholics. J Stud in male and female alcoholics. J Stud Alcohol (in press) 30. Pew R: The speed-accuracy operating characteristic. Attention Alcohol 49~282-287, 1988 15. Tharp V, Rundell 0, Lester B, Williams H: Alcohol and Infor- and Performance 11. Acta Psychol 30:16-26, 1969 3 1. Schaeffer KW, Parsons OA: Learning and memory test performmation processing. Psychopharmacologica40:33-52, 1974 16. Jennings R, Wood C, Lawrence B: Effects of graded doses of ance in alcoholics as a function of monetary incentive. Int J Neurosci alcohol on speed-accuracy tradeoff in choice reaction time. Percept 381311-319, 1988 32. Sharps M, Gollin E: Speed and accuracy of mental image rotation Psychophys 19~85-91,1976 17. Price D, Radwan M, Tergou R: Gender, alcohol, pacing and in young and elderly adults. J Gerontol42:342-344, 1987 33. SAS Institute, Inc: SAS User’sGuide: Statistics, Version 5 Edition. incentive effects on an electronics assembly task. Ergonomics 29:393Cary, NC, SAS Institute, Inc., 1985 406, 1986 34. Dixon WJ (ed): BMDP Statistical Software. Berkeley, CA, Uni18. Pojesz B, Begleiter H: Evoked potentials and alcoholism, in Parsons OA, Butters N, Nathan P (eds): Neuropsychology of Alcoholism: versity of California Press, 1983 35. Sinha R, Parsons OA, Glenn SW: Drinking variables, affective Implications for Diagnosis and Treatment. New York; Guilford Press, measures and neuropsychologicalperformance: Familial alcoholism and 1987, pp 45-63 19. Pachella R: The interpretation of reaction time in information gender correlates. Alcohol 6:77-85, 1989 36. Fabian MA, Parsons OA, Silverstein JA: Impaired perceptualprocessing research, in Kantowitz B (ed): Tutorials in Performance and cognitive functioning in alcoholic women: Cross-validated findings. J Cognition. NJ, Lawrence Erlbaum Associates, 1974 20. NCA: Criteria for the diagnosis of alcoholism. Am J Psychiatry, Stud Alcohol 41217-229, 1981 37. Wood D, Wender P, Reimherr F The prevalence of attention 129:2, 1972 2 1. American Psychiatric Association: Diagnostic and Statistical deficit disorder, residual type, or minimal brain dysfunction, in a population of male alcoholic patients. Am J Psychiatry 140:95-98, 1983 Manual of Mental Disorders, ed 3, revised. Washington, Dc;American 38. Glenn SW, Parsons OA: Alcohol abuse and familial alcoholism: Psychiatric Association, 1987 Psychosocial correlates in men and women. J Stud Alcohol 50: 116-127, 22. Shipley W A self-administeringscale for measuring intellectual 1989 impairment and deterioration. J Psychol 9:371-377, 1940 39. Emmerson RY, Dustman RE, Heil J, Shearer D E Neuropsycho23. Beck A: Depression: Clinical, Experimental and Theoretical Aslogical performance of young nondrinkers, social drinkers, and long- and pects. New York, Harper and Row, 1967 short-term sober alcoholics. Alcohol Clin Exp Res 12:625-629, 1988 24. SpielbergerC, Gorsuch R, Lushene R: Test Manual for the State40. Grant I, Adams K, Reed R Normal neuropsychological abilities Trait Anxiety Inventory. Palo Alto, CA, Consulting Psychologists Press, of alcoholics men in their late thirties. Am J Psychiatry 136:1263-1269, 1970 1979 25. Cahalan D, Cisin I, Crossley H: American Drinking Practices: A 41. Glenn SW, Parsons O A The role of time in neuropsychological National Study of Drinking Behaviors and Attitudes. Rutgers Center of performance: Investigation and application in an alcoholic population. Alcohol Studies Monograph No. 6, New Brunswick, NJ, 1969 Clin Neuropsychol4:344-354, 1990 26. Acker W, Acker C Bexley Maudsley Automated Processing 42. Harwood H, Kristiansen P, Rachal J: Social and economic costs Screening and Bexley Maudsley Category Sorting Test Manual. Great of alcohol abuse and alcoholism. Issue Report No. 2. Research Triangle Britain, NFER-Nelson Publishing Co, 1982 Park, NC, Research Triangle Institute, 1985 27. Berg E A simple objective technique for measuring flexibility in 43. Aitken SS, Zobeck T Trends in alcohol-related fatal motor accithinking. J Gen Psychol 39: 15-22, 1948 dents for 1983. Alcohol Health and Research World 9:60-62, 1985
0145-6008/91/1504-0612$3.00/0
ALCOHOLISM: CLINICAL AND EXPERIMENTAL RESEARCH
Effects of Alcoholism and Instructional Conditions on Speed/Accuracy Tradeoffs Susan W. Glenn and Oscar A. Parsons
The speed and accuracy of neuropsychological performance in alcoholics and nonalcoholics were assessed for each item within a four-test computerized battery. Subjects were randomly assigned to one of three instructional conditions: Speed-emphasis instructions, Accuracy-emphasis instructions, or Typical instructions emphasizing speed and accuracy equally. Across conditions, alcoholics were less accurate and took longer to perform than controls. Examining speed and accuracy components separately within each condition, as predicted, the greatest differences in accuracy scores between alcoholics and controls appeared in the Speed-emphasiscondition, while the greatest group differences in speed scores appeared in the Accuracy-emphasis condition. The results indicate that the relationships between speed and accuracy are dissimilar betweenalcoholics and controls; alcoholics exhibit speed/accuracy tradeoffs in that they are unable to adjust performance to meet speed or accuracy demands without suffering substantial compromise in the other aspect of performance. These results have implications for future studies concerning methodological approaches to speed and accuracy assessment and provide support for an information-processing deficit associated with chronic alcohol abuse. Key Words: Female Alcoholics, Instructional Effects, Neuropsychological Performance, Speed/accuracyTradeoffs.
LCOHOLISM HAS BEEN associated with dysfunction A in a variety of psychomotor, cognitive and behavioral tasks.',' Two variables commonly assessed in many of these tasks are the speed and accuracy of performance. These variables can be addressed from several perspectives including: (1) measuring the variables independently in separate tasks and (2) measuring overall performance as the changing relationships between speed and accuracy under differing experimental conditions. The approach used to assess speed and accuracy determines to some extent the methodology as well as the conclusions or interpretations that can be made. This paper will address the issues of speed and accuracy assessment in alcoholics and controls using both of these approaches. From the Department of Psychiatry and Behavioral Sciences, Center for Alcohol and Drug Related Studies, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma. Received for publication June 21, 1990; accepted January 16, 1991 The research was supported, in part, by the National Institute dn Alcohol Abuse and Alcoholism grant lR01-AA06135 to Dr. Oscar A . Parsons. This research was conducted in partial fulfillment of the Doctor of Philosophy degree by the first author, under the direction of the second author, at the University of Oklahoma Health Sciences Center. Reprint requests: Susan W. Glenn, Ph.D., Department of Psychiatry, Center for Alcohol and Drug Related Studies, 800 N.E. 15th Street, Rogers Building, Suite 410, Oklahoma City, OK 73104. Copyright 0 1991 by The Research Society on Alcoholism. 612
SPEEDANDACCURACYASSEPARATEMEASURES Alcoholics have been found to be slower and more variable in their responses when compared with nonalcoholic controls on both simple and complex reaction tasks.'-' Alcoholics also demonstrate longer search times in visual discrimination tasks6 and take longer than controls for fine motor performance7and problem-solving tasks.' Accuracy, or the percentage of correct responses for a given task, also shows alcohol-related deficits over a wide range of functions. Alcoholics have been found to be less accurate than controls in discrimination of both visual and auditory ~ t i m u l i . ~They ~ ~ * are ' ~ also less accurate in psychomotor tasks such as visual-perceptual construction and in memory and location for tactual-spatial information." On other cognitive tasks such as general information,12digit encoding," immediate and delayed memory and new learning," and problem-solving and abstracting,14 alcoholics make significantly more errors or perform less accurately than comparison controls. These two aspects of performance, speed and accuracy, are often assessed independently of each other, as seen in the exclusion of incorrect responses in the calculation of mean reaction time," and in the employment of response deadlines or preset accuracy requirements.16 When accuracy and speed are allowed to vary freely and are assessed simultaneously, however, the relationships between the two aspects of performance and the methods by which the two are balanced may be examined.
SPEED AN ACCURACY RELATIONSHIPS There is some suggestion that alcohol, whether taken acutely or chronically, may adversely affect the ability to self-monitor behavior, e.g., to optimally vary the speed and accuracy of p e r f ~ r m a n c e . 'Porjesz ~.~~ and Begleiter'. lo examined the two variables using electrophysiological measures in an easy and difficult line-orientation discrimination task. Their results revealed that alcoholics manifested more time for stimulus evaluation and, unlike controls, did not respond differentially as a function of task difficulty. The authors concluded that alcoholics exhibited deficits in the rapid and accurate processing of information, and they were unable to adjust performance to meet both speed and accuracy demands without substantial compromise. York and Beiderman7gave alcoholics instructions to work as quickly and as accurately as possible on a target-tapping test. Their results indicated that alcoholics showed a speed/accuracy tradeoff relative to controls in that increases in speed compromised the accuracy of their performance. Taken together, the results of Pojesz and Begleiter'' and of York and Beiderman7 suggest that alcoholism may impair both the speed and accuracy of visual and motor performance relative to controls. In addition, the relationships between speed and accuracy may also be affected by alcoholism in that increases in one factor are achieved by decreases in the other, reflecting a tradeoff or compromise in the capacity to maintain one aspect of performance while responding to other task demands. The present study sought to extend these findings to tasks of cognitive performance.
EXPERIMENTAL HYPOTHESES The purpose of the present study was to assess the speed and accuracy of neuropsychologicalmeasures under three instructional conditions that Alcohol Clin Exp Rex, Vol 15, No 4, 1991: pp 612-619
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vary in the emphasis placed on speed and accuracy: a condition emphasizing accuracy (0% errors) at the possible expense of speed (Accuracyemphasis condition), a condition emphasizing speed at the possible expense of accuracy (Speed-emphasis condition), and a condition emphasizing equal importance of both speed and accuracy (Typical-emphasis condition).’9The interrelationships between speed and accuracy measures were examined, and the two measures were examined as independent measures as well. It was expected that controls would demonstrate tradeoffs between performance factors in the various conditions such that speed instructions produce increases in speed with concomitant decreases in accuracy, and vice versa for accuracy instructions. It was hypothesized that alcoholic performance, however, would be characterized by such tradeoffs to a greater extent than controls. The following experimental hypotheses were tested:
Hypothesis I Alcoholics, compared with controls, will have lower accuracy scores and higher (take longer) speed scores on perceptual-cognitivetests.
Hypothesis 2 Alcoholics, compared with controls, will have greater trade-offs between speed and accuracy under different experimental conditions. Specifically, alcoholics (relative to controls) will show the greatest deficits in accuracy scores in the Speed-emphasis condition and will show the greatest deficits in speed scores in the Accuracy-emphasis condition.
METHOD Subjects The sample consisted of 48 female alcoholics recruited from alcoholism treatment centers in the Oklahoma City area, and 36 female nonalcoholic community controls. All alcoholic subjects had been diagnosed alcohol-dependent according to National Council on Alcoholism (NCA)” or DSM-111-R criteria” and had been detoxified for 3 to 6 weeks before testing. Subjects were excluded if screening interviews or medical charts revealed a history of neurological disease or trauma, major psychiatric disorder, acute medical problems such as cardiovascular or liver problems that could lead to central nervous system (CNS) dysfunction, or if they were currently receiving any psychoactive medication. All subjects were between 2 1 and 49 years of age, had at least an 8th grade education, and were of dull normal intelligence or higher as measured by the Shipley Vocabulary Scale?’ All subjects were administered the Beck Depression Inventory2’and the State Anxiety In~entory,’~ and they were given an interview concerning drinking and substance abuse experience. The interview data were used to construct a quantity-frequency index (QFI)” and the typical number of ounces drunk per drinking occasion. Alcoholics and controls were equated on relevant demographic variables and did not differ on the Beck or the State Anxiety Inventory (Table I). Informed consent documents were read and signed by each subject before testing and all received monetary compensation for their participation.
each task. These practice trials were not included in the mean reaction time or accuracy measures in the subsequent analyses, and the subjects were informed when the practice trials were completed and when the test trials began. Specific test measures are discussed below. Simple Reaction Time. This task required the subject to press a button each time a visual stimulus (a star) appeared on the computer screen. Three types of intertrial intervals (approximately 1, 2.5, and 5 sec) were presented in random order with a total of 75 trials. Only 60 of the 75 trials (20 of each of the three intertrial intervals) were included in the analyses; trials beyond the subject’s standard deviation range for that particular intertrial interval were not included. This task was included to assess whether any differences obtained on the cognitive tests could be attributed to a pervasive slowing of response to any stimulus. Visuospatial Orientation. This aspect of functioning was assessed by the “Little Men Test” (abbreviated LM)? The test required the subject to make right/left discriminations on a manikin which was rotated along two axes (up/down, front/back). The manikin, presented on the computer screen, held a briefcase in one hand; the objective was to determine which hand the case was in. Four practice trials were completed before the test began, allowing subjects to be familiarized with the four possible manikin positions. The subject then began the test and responded by pressing the “right” or the “left” key for each of the 32 test trials. VisualPerceptualSkills.The computerized Visual Perceptual Analysis (VPA)26required subjects to detect graduated differences in geometric patterns. Three five-by-four matrices were presented in each trial; the subject’s task was to identify the one matrix that differed from the other two. Four practice trials were given before the 24 test trials began. Problem-Solvingand Abstracting. This cognitive ability was assessed using the Bexley-Maudsley Category Sorting Test (BMCST),26a computerized version of the Wisconsin Card Sorting Test.” The test required subjects to use abstract concepts to develop sorting criteria and to modify these concepts to develop sorting criteria and to modify these concepts as the computer altered test solutions. The sorting criteria defined by the computer were the orientation of elements, number of elements, and the type of elements (rather than color, form, and number criteria used by the noncomputerized version of the test). Feedback concerning the accuracy of the subject’s response appeared on the screen following each sorting attempt. Six consecutivecorrect responsesconstituted a successful completion of one category; there were six categories to be sorted. Subjects did not receive practice problems on this test. Short-Term Memory. A version of the “Sternberg task”’’ was used to assess short-term memory. The subject was presented with a memory set of digits, ranging in set size from 1 to 6 digits. The digits were presented serially at the rate of l/sec. Immediately after presentation of the set, a signal was given (a plus sign) after which a probe digit was presented. The subject’s task was to indicate whether the probe digit was a member of the memory set. Following this “presence or absence” judgment, the subject was asked to recall the digits of the memory set. Twelve practice trials were given, and then the 48 experimental trials.
Procedure
As the subjects were participants in a larger study, the Efficiency Battery was administered in conjunction with several other assessment procedure^.^^ A battery of neuropsychological tests was administered in a morning testing session lasting approximately 2 to 3 hr. The subjects were given a lunch break, and then the Efficiency Battery was given, Materials followed by another break and an interview session concerning medical, All subjects were administered a simple reaction time task and a , social, and alcohol abuse histories. This testing order was the same for battery of tests that assessed those functions most frequently impaired in alcoholics and controls and was structured to maximize performance chronic alcoholism: problem-solving and abstracting, short-term mem- and reduce fatigue. The Efficiency Battery took approximately 1 hr to ory, visual-spatial skills, and perceptual analysis The tests complete and was administered by trained research assistants. All subjects were administered on an Apple I1 or I1 Plus computer, and both accuracy received the simple reaction time task first; the order of the remaining and speed were recorded for each test item. For each of the tests (except five tests was randomly preselected for each subject. Subjects were randomly assigned to one of the three experimental the Bexley-Maudsley Category Sorting Test,26for which practice trials were not available), several practice problems were administered before conditions, with 16 alcoholics and 12 controls in each. Before beginning the test began, allowing subjects to become familiar with the specifics of the battery, subjects were informed that this portion of the testing would
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assess both speed and accuracy aspects of performance. They were told that in order to examine the ways in which speed and accuracy affected overall performance, we would be studying performance under three different conditions; the experimenter then described each of the three performance conditions (see descriptions below). The rationale for informing subjects of the three possible conditions (instead ofjust her own condition assignment) was to illustrate for the subject the contrast between conditions in order to assist her in interpreting her conditionspecific performance requirements. For example, subjects could more clearly appreciate the meaning of accuracy-emphasis conditions if they also understood that other subjects would be working under speedemphasis conditions, and still others working under both speed- and accuracy-emphasis conditions. This method of pretest instruction is thought to help anchor high and low points of performance on the speedoperating characteristic curve,3oand to help subjects respond in experimenter-rather than individually-defined capacities.” We have reported that while alcoholics and controls may not perform at similar levels on various cognitive tests, they do not differ in their motivation to attempt to perform in accordance with experimental demands3’;therefore, we did not anticipate any group-specific effect of the pretest instructions. Subjects were not informed of the experimental hypotheses, nor of any anticipated differences in groups’ performances. Before beginning each test within the battery, specific instructions were given regarding task requirements, and the appropriate speed or accuracy performance instructions were reiterated. The three experimental conditions are described below: Accuracy-Emphasis Condition. Instructions were given to perform each task “as accurately as possible, taking as much time as necessary in order to make as few mistakes as possible.” Speed-Emphasis Condition. Instructions were given to perform each task “as quickly as possible, keeping in mind that some errors are acceptable as long as the effort is made to work as rapidly as possible.” Typical-EmphasisCondition. Instructions were given to perform each task “as quickly and as accurately as possible.” (Sharps and Collin3*have shown that the order of instruction, to “perform as quickly and as accurately,” or as “accurately and quickly” have the same effect on test performance.) Speed and accuracy were recorded for each test item. For analyses the means of accuracy and reaction times were used to create summary accuracy and speed scores for each of the tests (excluding simple reaction time). These summary scores were then standardized to a mean of 50 k 10 ( T scores). The statistical analyses were completed using the SAS33 and BMDP34statistical packages within the university mainframe computing system. To examine differences between alcoholicsand controls on speed and accuracy measures, the first experimental hypothesis, multivariate analyses of variance (MANOVAs) were conducted for group (alcoholic versus control) and instructional condition effects on the speed and accuracy scores of the four computerized tests. To address the second experimental hypothesis, simple effects analyses of the speed and accuracy scores for alcoholics and controls within each instructional condition were conducted to examine group differences as a function of condition. (Because some differences between alcoholics and controls were expected in each of the three instructional conditions, it was felt that simple effectsanalyses could best assess Hypothesis 2 despite the lack of group x condition main effect interactions.) Demographic characteristicsof the sample were compared using Student’s t test.
Table 1. Means (+SO) for Demographic Characteristics
Age Years education Beck depression inventory State anxiety Years of alcohol abuse Quantity frequency index (QFI) Typical ounces of ethanol
Alcoholics
Controls
(n = 48)
(n = 36)
32.8 (k7.2) 12.3 (k2.0) 6.3 (k6.8) 48.9 (59.2) 10.4 (k7.0) 13.3 (k13.0) 16.6 (514.9)
32.6 (56.2) 13.0 (k1.2) 4.2 (k5.3) 46.2 (k7.9) 0.12 (k0.21) 0.79 (k0.97)
Table 2. Means ( ~ s D for ) Reaction Time (in msec)
Accuracy emphasis condition Alcoholics Interval 1.O’ Interval 2.5 Interval 5.0 Controls Interval 1 .O Interval 2.5 Interval 5.0
Typical emphasis condition
Speed emphasis condition
Mean
279.3 (59.4) 270.4 (61.O) 268.9(38.6) 273.1 (53.4) 251 .I (48.4) 273.4(41.2) 258.5(49.6) 260.8(46.5) 266.9(54.4) 286.2(55.7) 270.1(47.1) 274.3(52.3) 267.3(49.6) 255.6(47.3) 249.6(40.6) 257.2(45.1) 256.1 (40.7) 242.4 (28.7) 231.9(28.8) 243.1 (33.5) 262.4(33.5) 249.3 (26.0) 235.7(27.1) 248.8(30.1)
* Intervals refer to the three intertrial intervals in seconds.
provide descriptive information concerning chronicity as well as pattern of alcohol abuse. The means for the alcoholics’ consumption variables are typical of those reported in other ~ t u d i e s ,indicating ~ ~ , ~ ~ that the sample is representative of the female alcoholic population. There were no significant group, condition, or group X condition effects on age, education, or anxiety scores. For depression scores, there was a significant effect of condition [F(5,71) = 5.60, p < 0.011, but there were no significant group differences or group x condition interactions. Subsequent analyses covarying for depression levels demonstrated that performance differences between alcoholic groups, or between alcoholics and controls, could not be attributed to the depression differences. Finally, alcoholic groups did not differ on the duration of alcohol abuse [F(2,45) = 1.88, p > 0.151, QFI [F(2,45) = 0.71, p > 0.481, or the typical ounces of ethanol consumed per drinking occasion [F(2,45) = 0.53, p > 0.581.
Simple Reaction Time Means for the simple reaction time task can be seen in Table 2. Using a group X condition X intertrial interval repeated measures analysis, alcoholics were significantly RESULTS slower overall than controls on reaction time [F(1,77) = Demographic characteristics of the sample are given in 4.26, p c 0.0441. A significant main effect of intertrial Table 1. As can be seen, alcoholics did not differ signifi- interval was found, [F(2,76) = 10.22, p < 0.0011; there cantly from controls on demographic variables of age or were no significant main effects of condition, or any group educational level or on affective measures of state anxiety x condition or intertrial interval X condition interactions. and depressive syrnptomatoIogy. Also listed for the sub- Further examination of the intertrial interval effect using jects in Table 1 are consumption variables in order to simple effects analyses indicated that the differences be-
615
ALCOHOLISM EFFECTS ON SPEED/ACCURACY TRADEOFFS
tween alcoholics and controls became greater as the intertrial interval increased [for 1.O-sec intertrial interval, F(1,77) = 1.84, p > 0.178; for 2.5-sec intertrial interval, F(1,77) = 3.62, p > 0.060; for 5.0-sec intertrial interval, F(1,77) = 6.53, p > 0.0121. Concerning the relationships between reaction time and other performance measures, correlational analyses were conducted between mean reaction time and the speed and accuracy scores of each of the four computerized tests. Of the 16 possible correlations, (eight for alcoholics and eight for controls), only one correlation was significant (for controls, mean reaction time and Sternberg speed score, r(1,35) = 0.506, p < 0.002). Importantly, there were no significant correlations between alcoholics' reaction times and performance on the test battery, illustrating that alcoholic performance deficits could not be attributed to differences between the groups in simple reaction time.
Speed and Accuracy Components In Table 3 are the speed and accuracy T scores for each experimental cell and in Table 4 are the results of the separate analyses for speed and accuracy scores. Turning first to the speed scores, a significant multivariate main effect of group was seen as alcoholics combined across conditions were slower than controls overall, and on each of the four computerized tests. Combining alcoholics and controls, a significant multivariate main effect of condition was seen as the speed scores differed among the three conditions. Significant univariate effects of condition were found for each test except the Sternberg. Examination of the means indicated that the speed scores for alcoholics and controls in the Accuracy-emphasis condition were the slowest in each case. The speed scores for alcoholics and controls were not differentially affected by the instructional conditions, however, as there were no group X condition interactions. Examination of accuracy scores revealed a significant group main effect, demonstrating that alcoholics (combined across conditions) were less accurate overall than controls and had significantly lower accuracy scores on the LM, BMCST and Sternberg tests. Main effects of
condition were found as well, and accuracy scores were significantly different between the three instructional conditions in the overall multivariate analysis and showed significant univariate effects on two of the four computerized tests (LM and VPA). On these two tests the lowest accuracy scores of the three alcoholic groups and the three control groups were found in the Speed-emphasis condition. As in the analysis of speed scores, there were no group X condition interactions for accuracy scores. Examining alcoholics and controls for between-group differences within each instructional condition, comparison of alcoholicsand controls within the Accuracy-emphasis condition indicated that the two groups did not differ in accuracy scores (Table 5). However, alcoholics had significantly slower speed scores than controls both overall and on each of the four tests. In the Speed-emphasis condition alcoholics were also significantly slower than controls overall and on two of the individual tests (VPA and Sternberg). Comparing accuracy scores under Speedemphasis instructions, alcoholics were less accurate than controls overall and on the BMCST and Sternberg individual tests. Interestingly, in the Typical-emphasiscondition alcoholics did not differ from controls on speed or accuracy measures. To summarize these results, the greatest differences in accuracy scores between alcoholics and controls on the computerized tests appeared in the Speed-emphasis condition, with alcoholics in this condition performing less accurately than controls both overall and on two of the four individual tests. There were no significant differences between alcoholics and controls on accuracy scores in either the Accuracy-emphasis or the Typical-emphasis conditions. Conversely, the greatest differences in speed scores appeared in the the Accuracy-emphasis condition, in which alcoholics were slower than controls on all four of the tests. Overall group differences for speed scores were also found in the Speed-emphasis condition, with alcoholics differing from controls on two of the four tasks in this instructional condition. These results provide support for Hypothesis 2. In terms of tradeoffs between speed and accuracy, alcoholics generally appear to trade speed for
Table 3. T Scores (im) for Speed and Accuracy Dependent variables',t Controls Instructional condition
Alcoholics Instructional condition
~~
~
LM Accuracy LM Speed VPA Accuracy VPA Speed BMCST Accuracy BMCST Speed Sternberg Accuracy Sternberg Speed
-~
Accuracy emphasis
Typical emphasis
speed emphasis
Mean
Accuracy emphasis
Typical emphasis
speed emphasis
Mean
49.3 (10.1) 61.1 (13.9) 52.8 (4.5) 59.8 (14.1) 47.8 (11.1) 61.3 (16.1) 49.6 (10.8) 56.0 (9.4)
49.6 (10.1) 47.9 (8.0) 50.8 (6.6) 48.0 (5.5) 51.0 (10.1) 46.8 (2.8) 51.7 (7.8) 51.1 (10.7)
44.6 (9.2) 48.0 (8.4) 44.7 (14.8) 49.5 (8.4) 44.5 (12.3) 47.9 (5.8) 42.0 (13.7) 53.4 (10.9)
47.9 (10.1) 52.5 (12.0) 49.5 (9.9) 52.5 (11.2) 47.8 (11.2) 52.1 (11.9) 47.9 (11.5) 53.5 (10.3)
55.7 (6.9) 49.6 (5.4) 55.8 (1.3) 51.1 (8.1) 54.2 (6.5) 52.2 (6.8) 52.8 (7.8) 49.4 (9.0)
54.3 (9.7) 46.7 (3.9) 53.1 (5.2) 47.3 (3.5) 51.7(10.4) 46.4 (3.4) 51.4 (8.3) 45.8 (5.4)
48.2 (10.0) 44.1 (4.4) 43.0 (14.1) 41.9 (6.1) 52.6 (4.4) 43.2 (2.3) 53.2 (4.6) 40.9 (5.8)
52.7 (9.3) 46.8 (5.0) 50.6 (10.1) 46.8 (7.1) 52.8 (7.4) 47.3 (5.8) 52.5 (6.9) 45.4 (7.6)
~
~
* LM, Little men; VPA, visual perceptual analysis; BMCST, Bexley-Maudsley Category Sorting Test.
t T Scores were calculated on the basis of the combined distribution of alcoholics and controls. Note that the higher the T score the better the accuracy performance while the higher the T score for speed, the longer time taken to perform the task.
616
GLENN AND PARSONS
and controls in the Typical-emphasjscondition was somewhat surprising. However, there were no significant group Groupt Condition* x condition interactive effects for performance scores F P F P across the three conditions for either alcoholicsor controls, Speed multivariate 5.50 0.0006 4.47 0.0002 illustrating that the performances of alcoholics and conS p e d univariates trols in the Typical-emphasis condition were not greatly Little men 8.80 0.0040 9.70 0.0002 Visual-perceptual 8.79 0.0040 9.79 0.0002 different from the performances of their respective groups BMCST 6.76 0.0112 15.57 0.0001 in the other two conditions. Stemberg 16.50 0.0001 2.76 0.0696 The alcoholicsin the current study were relatively young Accuracy multivariate 2.56 0.0457 2.66 0.0094 (early 30s) compared with the typical age range of studies Accuracy univariates Little men 5.30 0.0241 3.39 0.0389 with male alcoholics (40s-60s). Several studies using 0.35 NSS 9.54 0.0002 Visual-perceptual younger male alcoholics of similar age as the current 5.45 0.0222 0.69 NS BMCST 4.98 0.0285 1.42 NS female subjects have reported equivocal findings with Stembera regard to cognitive deficits; some studies have found eviThere were no significant interactions involving the performance measures and conditions. dence of alcohol-related deficits while others have t Group multivariate (df = 4,74) for Speed and Accuracy analyses; group While there were no significant differences in age across univariate (df = 1.77). conditions, it is possible that the failure to find consistent *Condition multivariate (df = 8,148); condition univariate (df = 2,77). 5 NS, not significant. alcohol-related performance deficits across conditions in the present study is partially due to the age of the subjects, accuracy. That is, while alcoholics showed no impairment and the tendency to find inconsistent results when dealing in accuracy scores relative to controls in the Typical- or with younger alcoholics. Future replication studies may Accuracy-emphasis conditions, speed scores for alcoholics further explain the performance of subjects in the Typicalwere slower than controls for most of the tests in both the emphasis condition. Accuracy-emphasis and Speed-emphasis conditions. Table 4. Multivariateand Univariate Analyses Of Speed and Accuracy Scores (Main Effects)'
~~
Speed-AccuracyRelationships and Condition Efects DISCUSSION
Simple Reaction Time The alcoholics in the sample were significantly slower than controls on the simple reaction reaction time task, supporting results from other studies using male alcoholic^^,^ and extending the use of reaction time tasks to female alcoholic populations. The differences between alcoholics and controls in reaction time became greater as the amount of time in the intertrial interval increased, with the 5-sec interval of Trial Type Three providing the largest group differences. Because increases in intertrial intervals require greater sustained attention and concentration than the shorter intervals, it is possible that the attention deficit disorder symptoms common in alcoholic population^^^,^^ are instrumental in the manifestation of deficits on these types of tasks.
Alcoholic Deficits in Speed and Accuracy As demonstrated by the main effects (Table 4),alcoholics as a group were significantly less accurate and slower than controls on each of the tests within the battery, providing support for the first experimental hypothesis. The results of the performance differences in speed aGd accuracy scores between alcoholics and controls in the Speed-emphasis and Accuracy-emphasis conditions indicate that relationships between the speed and accuracy of performance were affected by instructional conditions as well as by alcoholism. The lack of significant differences between alcoholics
The relationships between speed and accuracy are best demonstrated using the speed-accuracy operating characteri~tic.~'This operating characteristic can be used to represent graphically the relationships between speed and accuracy across experimental conditions. These curves plot the average response latency against the mean accuracy of responses for each of the various conditions. Ideally, the Speed-emphasiscondition anchors the bottom portion of the curve where response time is fast and accuracy is low. The Accuracy-emphasis condition, on the other hand, represents the top portion of the curve where accuracy is high and response times are slow. The Typicalemphasis condition falls into the middle portion of the curve between the other two conditions. It was anticipated that in this study the performance of the controls would reflect this ideal operating characteristic. Figs. 1 and 2 (the LM and VPA tests) demonstrate the expected relationship between the controls in the three conditions and illustrate that the alcoholics' speed-accuracy operating characteristisc were shifted downward and to the right, reflecting large tradeoffs and apparent differences in basic speedaccuracy relationships between alcoholics and controls. For example, on these two tests controls were the most accurate and the slowest in the Accuracy-emphasis condition, and vice versa for the Speed-emphasis condition, and vice versa for the Speed-emphasis condition. Alcoholics, on the other hand, were equally or less accurate in the Accuracy-emphasiscondition than the Typical-emphasis condition, and were even slower in the Speed-emphasis condition than in the Typical-emphasis condition. The speed-accuracy curves for the BMCST and the
617
ALCOHOLISM EFFECTS ON SPEED/ACCURACY TRADEOFFS
Figure 1
Figure 2
Llttle Men
Vlsuoperceptual
60
62-
60-
58-
58
--
A
A
- - - - - - -0
-----
o - - - - - - - - - - - _ _ _ _ _ _ - - *
46-
I I
46U -
46-
u-
5 b
u-
u
40
Speed Scores
Speed Scores Alwhollcl
*
Alaohollas
Controls
Controls
Figure 4 Sternberg Aaauraq Saanr 6058
58-
56
-
A
46-
\
U 42-
5 0
0
:I Alwhollas
*
Coniralr
\ \ \
44
\
u
sb
Alooholkr
*
Contmlr
Figs. 1-4.
Table 5. Simple Effects Analyses for Speed and Accuracy Scores: By Condition Accuracy emphasis condition
Typical emphasis condition
speed. emphasis condition
P
F
P
F
P
4.17
0.004
0.61
NSS
3.40
0.013
12.86 7.02 8.50 3.66
0.001 0.009 0.005 0.059
0.15 0.04 0.01 2.37
NS
NS
1.44 5.17 2.17 12.71
0.001
1.18
NS
0.49
NS
2.95
0.025
3.01 0.73 2.92
NS
NS
NS
0.92 0.24 4.60 9.25
NS
0.80
1.69 0.45 0.03 0.01
F Speed scores Multivariate' Univariatest LM VPA BMCST Sternberg Accuracy scores Multivariate. Univariatest LM VPA BMCST Stemberg
* Multivariate (df = 4,74). t Univariates (df = 1.77).
*
NS,
not significant.
NS NS
NS NS
NS NS NS
NS
0.026 NS
NS
0.035 0.003
Sternberg tests are presented in Figs. 3 and 4. Perhaps because these tests assess problem-solving and memory functions rather than choice visual discriminations, the speed-accuracy curves for the controls as well as alcoholics do not fit the ideal speed-accuracy operating characteristic. It is apparent for each of these speed-accuracy curves, however, that the relationships between speed and accuracy are dissimilar for alcoholics and controls, reflecting alcoholics' apparent difficulties when required to rapidly or accurately process information, and to adjust performance to meet speed or accuracy demands without substantial compromise in the other aspect of performance. These results may be construed as an extension of the findings seen in electrophysiological studies of chronic alcoholics. As the results of Porjesz and Begleiter','' have indicated, alcoholics demonstrate difficulties in distinguishing relevant from irrelevant stimuli. For example, in tasks utilizing target and nontarget stimuli, alcoholics' electrophysiological response is often similar to both types of targets while controls exhibit large responses to target
GLENN AND PARSONS
618
stimuli and small responses to nontargets. Further studiesI8 suggest that the lack of response discrepancy between targets and nontargets reflects alcoholics’ tendencies toward uniform, rather than dynamic, adaptive responses to changing environmental stimuli. In the present study, the instructions in the Typiculemphasis condition represented the most common type of instructions seen in testing situations. Instructions were given to work “as quickly and as accurately as possible.” Because these Typical instructions were most like those given in other testing situations they may have been the most familiar and least difficult or stress-provoking type of instructions. Given these instructions, alcoholics were able to perform as well as controls. However, the instructions for the Speed- and Accuracy-emphasis conditions, less common in testing situations, require the subject to prioritize, or channel, efforts toward one aspect of their performance over the other. The results suggest that controls are able to channel efforts to meet specific performance demands, while at the same time maintaining adequate levels of performance in the nonspecified aspect. Alcoholics, on the other hand, are characterized by an inability to perform well under novel, nontypical instructions. That is, they are unable to cognitively “shift gears” from the usual mode of functioning to focus on only one aspect of their performance without suffering substantial compromise in the other aspect of performance to which they are not attending. This suggestion has potential implications for gaining a better understanding of the cognitive deficits associated with alcoholism and deserves further attention and replication.
available; (3) this study illustrates clearly that special consideration should be given to the instructional set provided at the beginning of any testing session. Significant condition effects were found for both alcoholics and controls, suggesting that both groups are sensitive to, and respond quite differently, when given instructions emphasizing speed or accuracy, or both; and (4) the failure of alcoholics to adequately manage either speed or accuracy components of performance suggests an information processing deficit sensitive to the presence of alcohol abuse. Perhaps it is this last point that offers the greatest relevance for day-to-day circumstances. Many situations in the everyday world call for the rapid or accurate evaluation of incoming information such as driving, assemblyproduction tasks, operation of heavy machinery, and even the successful completion of standardized education tests. In the United States alone, over $70,905 million are lost each year due to lost employment or decreased productivity caused by alcohol and 17,847 lives lost in alcohol-related traffic accidents,43 illustrating potential cases in which inadequate tradeoffs between speed and accuracy may have caused detrimental or even deadly consequences. Clearly, the further investigation of speedaccuracy relationships in alcoholics merits careful and thorough consideration. ACKNOWLEDGMENTS We appreciate the help of Cynthia Kelley, B.A., and Jatinder Singh, M.S., in administering the battery to the subjects. We also thank Sara Jo Nixon, Ph.D., for her constructive comments on this paper,
REFERENCES
Implications for Future Research The findings of the present study illustrate the deficits in speed-accuracy relationships in female alcoholics. Given the number of studies that have included only male alcoholics, there is a relative paucity of studies in the literature that examine alcohol’s effects on female cognitive functioning; this study provides an important contribution to that body of scientific knowledge. A limitation of the current study, however, is the inclusion of only female subjects, as there is some evidence in both acute alcohol administration and chronic alcohol abuse that speed and accuracy are affected differentially by gend e r . ” ~Further ~ ~ studies are needed to examine the role of gender in speed and accuracy relationships. The findings of this study also have several implications for future studies in both methodological and application areas: (1) measures of speed and accuracy can be assessed from several different perspectives; the particular approakh adopted influences the methodology and the nature of the conclusions that can be drawn; (2) the Efficiency Battery used in this study is primarily computerized and takes only an hour to administer, suggesting potential uses even in situations where the time or resources needed for a complete traditional neuropsychological battery are un-
1. Tarter R Brain damage in chronic alcoholics: A review of the psychologicalevidence, in Richter D (ed): Addiction and Brain Damage. London, Croom and Helm, LTD, 1980 2. Parsons OA: Alcoholics’neuropsychologicalimpairment: Current findings and conclusions. Ann Behav Med 8:13-19, 1986 3. Carpenter J: Effects of alcohol on some psychological processes: A critical review with reference to driving skill. Q J Stud Alcohol 23:274313, 1962 4. Talland G: Psychological studies of Korsakoffs psychosis: V. Spontaneity and activity rate. J Nerv Ment Dis 130:16-25, 1960 5. Talland G: Alcoholism and reaction time. Q J Stud Alcohol 24610-621, 1962 6. Bertera J, Parsons OA: Impaired visual search in alcoholics. Alcohol Clin Exp Res 2:9-14, 1978 7. York J, Beiderman I: Motor performance in detoxified alcoholics. Alcohol Clin Exp Res 12:119-124, 1988 8. Klisz D, Parsons OA: Hypothesis testing in young and older alcoholics. J Stud Alcohol 38: 1718- 1729, 1977 9. Pojesz B, Begleiter H: Event-relatedpotentials and decision time in chronic alcoholics. Paper presented at the International Council on Alcohol Abuse, Vienna, Austria, 1981 10. Pojesz B, Begleiter H: Event-related potentials in chronic alcoholics. Paper presented at the 134th Annual Meeting of the American Psychiatric Association, New Orleans, LA, 1981 11. Noonberg A, Goldstein G, Page H: Premature aging in male alcoholics: “Accelerated aging” or “Increased Vulnerability”? Alcohol Clin Exp Res 9:334-338, 1985 12. Tarter R Psychological deficit in chronic alcoholics: A review. Int J Addict 10:327-368, 1975
ALCOHOLISM EFFECTS ON SPEED/ACCURACY TRADEOFFS
619
28. Sternberg S: The discovery of processing stages: Extensions of 13. Schaeffer K, Parsons OA: Learning impairment in alcoholics using an ecologically relevant test. J Nerv Ment Dis 175:2 13-2 18, 1987 Donder’s method, Acta Psychol 30:276-3 IS, 1969 29. Glenn SW, Parsons O A Neuropsychological efficiency measures 14. Turner J, Parsons OA: Verbal and nonverbal abstracting-problem-solving abilities and familial alcoholism in female alcoholics. J Stud in male and female alcoholics. J Stud Alcohol (in press) 30. Pew R: The speed-accuracy operating characteristic. Attention Alcohol 49~282-287, 1988 15. Tharp V, Rundell 0, Lester B, Williams H: Alcohol and Infor- and Performance 11. Acta Psychol 30:16-26, 1969 3 1. Schaeffer KW, Parsons OA: Learning and memory test performmation processing. Psychopharmacologica40:33-52, 1974 16. Jennings R, Wood C, Lawrence B: Effects of graded doses of ance in alcoholics as a function of monetary incentive. Int J Neurosci alcohol on speed-accuracy tradeoff in choice reaction time. Percept 381311-319, 1988 32. Sharps M, Gollin E: Speed and accuracy of mental image rotation Psychophys 19~85-91,1976 17. Price D, Radwan M, Tergou R: Gender, alcohol, pacing and in young and elderly adults. J Gerontol42:342-344, 1987 33. SAS Institute, Inc: SAS User’sGuide: Statistics, Version 5 Edition. incentive effects on an electronics assembly task. Ergonomics 29:393Cary, NC, SAS Institute, Inc., 1985 406, 1986 34. Dixon WJ (ed): BMDP Statistical Software. Berkeley, CA, Uni18. Pojesz B, Begleiter H: Evoked potentials and alcoholism, in Parsons OA, Butters N, Nathan P (eds): Neuropsychology of Alcoholism: versity of California Press, 1983 35. Sinha R, Parsons OA, Glenn SW: Drinking variables, affective Implications for Diagnosis and Treatment. New York; Guilford Press, measures and neuropsychologicalperformance: Familial alcoholism and 1987, pp 45-63 19. Pachella R: The interpretation of reaction time in information gender correlates. Alcohol 6:77-85, 1989 36. Fabian MA, Parsons OA, Silverstein JA: Impaired perceptualprocessing research, in Kantowitz B (ed): Tutorials in Performance and cognitive functioning in alcoholic women: Cross-validated findings. J Cognition. NJ, Lawrence Erlbaum Associates, 1974 20. NCA: Criteria for the diagnosis of alcoholism. Am J Psychiatry, Stud Alcohol 41217-229, 1981 37. Wood D, Wender P, Reimherr F The prevalence of attention 129:2, 1972 2 1. American Psychiatric Association: Diagnostic and Statistical deficit disorder, residual type, or minimal brain dysfunction, in a population of male alcoholic patients. Am J Psychiatry 140:95-98, 1983 Manual of Mental Disorders, ed 3, revised. Washington, Dc;American 38. Glenn SW, Parsons OA: Alcohol abuse and familial alcoholism: Psychiatric Association, 1987 Psychosocial correlates in men and women. J Stud Alcohol 50: 116-127, 22. Shipley W A self-administeringscale for measuring intellectual 1989 impairment and deterioration. J Psychol 9:371-377, 1940 39. Emmerson RY, Dustman RE, Heil J, Shearer D E Neuropsycho23. Beck A: Depression: Clinical, Experimental and Theoretical Aslogical performance of young nondrinkers, social drinkers, and long- and pects. New York, Harper and Row, 1967 short-term sober alcoholics. Alcohol Clin Exp Res 12:625-629, 1988 24. SpielbergerC, Gorsuch R, Lushene R: Test Manual for the State40. Grant I, Adams K, Reed R Normal neuropsychological abilities Trait Anxiety Inventory. Palo Alto, CA, Consulting Psychologists Press, of alcoholics men in their late thirties. Am J Psychiatry 136:1263-1269, 1970 1979 25. Cahalan D, Cisin I, Crossley H: American Drinking Practices: A 41. Glenn SW, Parsons O A The role of time in neuropsychological National Study of Drinking Behaviors and Attitudes. Rutgers Center of performance: Investigation and application in an alcoholic population. Alcohol Studies Monograph No. 6, New Brunswick, NJ, 1969 Clin Neuropsychol4:344-354, 1990 26. Acker W, Acker C Bexley Maudsley Automated Processing 42. Harwood H, Kristiansen P, Rachal J: Social and economic costs Screening and Bexley Maudsley Category Sorting Test Manual. Great of alcohol abuse and alcoholism. Issue Report No. 2. Research Triangle Britain, NFER-Nelson Publishing Co, 1982 Park, NC, Research Triangle Institute, 1985 27. Berg E A simple objective technique for measuring flexibility in 43. Aitken SS, Zobeck T Trends in alcohol-related fatal motor accithinking. J Gen Psychol 39: 15-22, 1948 dents for 1983. Alcohol Health and Research World 9:60-62, 1985
