Psychological Reports, 1976, 38, 1003-10 10. @ Psychological Reports 1976
ROLE OF SELECTIVE AITENTION T O EMOTIONAL AND NEUTRAL STIMULI I N SCHIZOPHRENIC AFFECTIVE DEFICIT1 CHARLES G. WATSON AND LYLE JACOBS Veterans Administration Hospital, St. Cloud, Minnesota Sumrna~y.-A test of the hypothesis that psychopathological emotional deficit involves selective attention to unemotional stimuli was made. The attention of schizophrenics ( ? I = 100) with high and low scores on measures of anhedonia and sensation-seeking to pleasant, unpleasant and neutral stimuli was contrasted. N o differences in the mean attention scores of the groups appeared. The results do not support the hypothesis. Emotional deficit in schizophrenia does not seem to result from selective attention to nonemotional stimuli.
It appears that psychiatric patients suffer from two disrinct emotional deficits. The first, anhedonia, has been described by Rado (1962) as a low general level of motivation, and an inability to experience such positive emotions as joy, zest, pride, and desire. Watson and Jacobs (unpublished) have noted that it tends to be associated with schizophrenic psychopathology. The second deficit, reduced sensation-seeking, reflects a restricted interest in adventure, thrills and uninhibited behavior. Despite their conceptual similarity, the two deficits appear to be unrelated." Although these phenomena are well-known among clinicians, their etiologies in psychiatric patients are unclear. Rado (1962) has theorized that anhedonia is a largely genetic disorder which precipicates a variety of schizophrenic performance deficits by undermining the motivating strength of positive emotions such as joy, pride, desire, and zest. Meehl (1962) has further suggested that defects in those cencers in the brain which mediate positive reinforcements could create a predisposition to schizophrenic behavior by weakening the ability of positive reinforcers co suengthen socially appropriate behaviors, thus increasing the probability of interpersonal aversiveness, disordered thought, unconventional verbalizations and other schizophrenic tendencies. Research on anhedonia has been sparse. Kayton and Koh (1975) have found that the free recall of pleasanc words in schizophrenics is, in facr, poorer than that for nonschizophrenics and normal controls, even though their recall of unpleasant words was no different from that of the other two groups. Their work tends to document the presence of anhedonia in schizophrenics. Wise and Stein (1973) noted that the level of dopamine-P-hydroxylase enzyme in 'This study was supported by the Veterans Administration Medical Research Service. MRIS No. 0298-05. The authors are indebted to John Swenson, James Olson, Gail Bamber, Norbert Kollodge. William Daly, Bruce Watkins. Teresa Kucala, Helen Buerkle, and Kathy Mack for their contributions to the project Requests for reprints should be sent to Charles G. Watson, Research Service, Veterans Administration Hospital. St. Cloud, Minnesota 56301. 'C. G. Watson & L. Jacobs. Evidence for a dual-factor concept of psychopathological emotional deficit; anhedonia and sensation-seeking. (Unpublished manuscript)
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the brains of schizophrenics is deficient. Since this enzyme is involved in the mediation of reward, they suggested that it may be responsible for anhedonia and thus provide a physiological explanation for the phenomenon. By comparing the learning of high- and low-anhedonic schizophrenics under primary, secondary, and social rewards and punishments, Watson (1972a) tested the hypotheses that anhedonia ( a ) stems from specific physiological dysfunctions in pleasure-mediating centers and ( b ) represents no more than the aversion of some schizophrenics to other human beings. His results did not support either theory. To determine whether anhedonia is related to physiological arousal level, Watson ( 1972b) also studied the correlations between Anhedonia scores and pulse, blood pressure, and tremulousness under resting and stress conditions. None of the correlations was significant. Additionally, he found Anhedonia scores unrelated to electrical stimulation threshold. While not conclusive, these results tend to undermine the view that anhedonia is physiologically based. Other research has suggested that the sensation-seeking dimension may be relevant to emotional deficit. Sensation-seeking is typically (e.g., Berlyne, 1960) described as an internal need for stimulation which, when not met, leads to boredom and, thence, to the pursuit of adventure. While this construct has more often been invoked as an explanation for antisocial behavior and uninhibitedness, it seemed possible that the high autonomic responsiveness of schizophrenics and neurotics may lead to abnormally low sensation-seeking needs and, thus, to the low emotionality in these groups. However, the extent to which this formulation applies to schizophrenic and neurotic behavior is, as yet, unknown. Thus, the mechanisms behind psychopathological emotional deficit are essentially unknown at present. The present paper describes a study designed to test another hypothesis on the etiologies of anhedonia and sensation-seeking. In the formulation researched here, these defects in positive affect are viewed as defenses against the unpleasant effects of emotional arousal. One method of defending against arousal is selectively to attend to neutral, rather than emotional, stimuli when given the choice. To evaluate this formulation, the experimenters presented pairs of pleasant-neutral, unpleasant-neutral and pleasant-unpleasant visual stimuli to schizophrenics varying on anhedonia and sensation-seeking measures for 10-sec. periods. It was hypothesized that, when compared to their less anhedonic and/or more sensation-seeking counterparts, patients with high levels of these affectual defects would attend to the neutral stimuli for longer periods of time than they would the pleasant and unpleasant ones.
METHOD Subjects
The subjects were 100 male schizophrenics at the St. Cloud (Minnesota) Veterans Administration Hospital, a 1,002-bed psychiatric hospital. All were
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volunteer subjects under the age of 60 in whose clinical files there was no evidence of brain damage. The mean age, education, total months of psychiatric hospitalization and SRA Tests of Educational Ability-based estimates (Watson & Klett, 1973) of Wechsler Adult Intelligence Scale IQ (and their standard deviations) of the 100 were: 35.6 yr. (10.8), 11.5 yr. (2.3), 43.5 mo. (@.0), and 102.1 ( 1 1.9). The means (and standard deviations) on the anhedonia and sensation-seeking variables were: Anhedonia Interview-12.5 (4.4); General Sensation-seeking-7.7 (3.9)'; Thrill and Adventure-seeking-6.6 (3.6); Experience-seeking-5.5 (3.6); Disinhibition--4.6 (2.7), and Boredom Susceptibility-5.2 (2.4). Quartile Matching The subjects were divided into quartiles on each of the six independent variables and the quartiles compared for mean attention time to pleasant, unpleasant and neutral stimuli in a procedure described below. Because of their possible effects as contaminants, the four quartile groups for each independent variable were first matched for mean age, education, length of hospitalization, and I Q estimates. The mean ages of the four Anhedonia quartiles were not significantly different from one another but the mean ages of the General Sensation-seeking, Thrill and Adventure-seeking, Experience-seeking, Disinhibition and Boredom Susceptibility scale quartiles either were significant or approached significance at the .05 level (Fs = 4.72, 4.02, 6.74, 4.08, and 1.99 respectively; all dfs = 3/96). In each case scores on the Sensation-seeking variables and age were negatively correlated. Additionally, the differences between the mean total months of psychiatric hospitalizations across quartiles for the Anhedonia, General Sensation-seeking and Experience-seeking scales were significant at the .20 level (Ps = 2.58, 1.78, and 1.69 respectively, dfs = 3/96), hospitalization tending to be positively correlated with affectual deficit. Moreover, the differences between the mean IQ estimates of the four Thrill and Adventure-seeking quartiles approached significance ( F = 1.79, dfs = 3/96, p < .20). N o differences approaching significance appeared on education. Matching for these demographic variables necessitated the removal of three, four, four, five, three, and one subject(s) respectively from each quartile in the analyses of Anhedonia, General Sensation-seeking, Thrill and Adventureseeking, Experience-seeking, Disinhibition, and Boredom Susceptibility respectively. After this had been achieved, no differences significant at the .20 level remained on any of the demographic variables. Thus, the number of subjects in each quartile varied between 20 and 24 in the six sets of analyses. Additional t tests were run to check for differences on mean age, length of hospitalization, education and estimated IQ between the first and fourth quarciles each of the Anhedonia and Sensation-seeking scales. None approached significance. Measures of Affective Deficit The independent measures used were the semi-structured Anhedonia Inter-
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view scale developed by Watson, Klett, and Lorei (1970) and Zuckerman's ( 1971 ) five Sensation-seeking scales. The former consists of five multi-point ratings dealing with lack of feeling, drive, hobbies and social interests, and avoidance of responsibility. Its internal consistency and test-retest reliability have been reported as .76 and .82 respectively (Watson, 1972a). The Sensation-seeking scales are factor-analytic self-report measures named General Sensation-seeking, Thrill and Adventure-seeking, Experience-seeking, Disinhibition, and Boredom Susceptibility. Their derivation and composition are described by Zuckerman (1971) in more detail.
Stimuli The subjects were exposed to sets of positive-, negative- and neutralcontent photographs taken from advertisements and feature stories in news magazines. One hundred and thirty-eight photos, deliberately chosen because they seemed (to the senior author) to have particularly pleasant, unpleasant or emotionless content, were clipped and presented to four judges (hospital employees naive as to the purpose of the project) with instructions to sort them into pleasant-, unpleasant- and neutral-content piles. Pictures which were not viewed by all four judges as falling into a particular category were eliminated. The judges were also instructed to rank-order the pictures within each pile for strength of positive, negative and nonemotional content. Those six pictures in each category which received the highest ratings were then tentatively defined as Positive-, Negative- and Neutral-stimulus content scales. The stimuli were presented to the subjects in pairs consisting of the most pleasantunpleasant, pleasant-neutral, and unpleasant-neutral pairs, the second most pleasant-unpleasant, pleasant-neutral and unpleasant-neutral pairs, etc. Thus each stimulus was presented twice to every subject. As Chapman and Chapman (1973) have noted, it is critically important that the reliability of dependent variables be matched in studies in which the performances of groups on several criteria are to be compared since failure to do so undermines the validity of across-criterion comparisons. Consequently, a pilot study was run to equate the sets of pleasant, unpleasant, and neutral stimuli for reliability. As is mentioned above, the stimuli consisted of 18 pairs of pleasant-unpleasant, pleasant-neutral and unpleasant-neutral stimuli, six in each combination. These 18 pairs were administered to 20 schizophrenic patients who were not subsequently employed in the main study. The amount of time during 10-sec. exposure intervals during which the subjects attended to the positive, negative and neutral stimuli in each of the 12 pairings was recorded. Attention time to each stimulus was considered as a response to a scale item and Hoyt alpha reliability coefficients were then calculated separately for the Positive, Negative, and Neutral sets of stimuli. The alphas-.42, . 5 5 , and .53 respectively-were quite low. In order to improve the reliability, all stimulus items whose correlations with their respective scale score totals were less than
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.30 were eliminated. This procedure produced Positive, Negative, and Neutral scales consisting of 8, 10, and 9 pictorial stimuli each. The alpha coefficients for the modified scales were more acceptable-Positive stimuli, .73; Negative stimuli, 1.59; and Neutral stimuli, .63 respectively. Moreover an F based on the ratio of the squares of the largest and smallest of these two correlations (P = 1.35, dfs = 19/19) fell far short of significance indicating that the reliabilities of the sets of stimuli did not differ significantly. Thus, it was assumed that differences between the scores of the groups on the three scales could be compared meaningfully. The positive pictures finally employed included five photographs-(a) two smiling baseball players jumping into the air, perhaps in celebration of a victory; ( b ) a pretty 5-yr.-old girl, her head cocked to one side, smiling into the camera; ( c ) a handsome young couple smiling and chatting by the sea; ( d ) a man and a semi-nude woman in a lusty embrace; and ( e ) an attractive young woman licking an ice cream cone. The negative stimuli were pictures of ( a ) the mutilated bodies of seven executed men squeezed into narrow wooden caskets; ( b ) a blood-spattered man being machine-gunned to death; ( c ) a soldier grimacing in pain as a serious wound is cleaned; ( d ) the bloody and bandaged face of a tired looking old woman; ( e ) the bullet-riddled, bloodied body of a man lying on a trash pile; and ( f ) a tearful woman leaving a casket at the conclusion of a funeral. The neutral stimuli included a picture of college students listening to a lecture, an expressionless old man, a bottle of inexpensive whiskey, and three pictures of expressionless middle-aged men. Another positive stimulus, that of a 3-yr.-old boy with his head thrown back in laughter, was eliminated during the process of matching for reliabilit~.~The magazine pictures were then photographed and reproduced as 8- X 11-in. black and white glossy prints. The prints were all equated for over-all brightness using a General Electric Type 213 footcandle lightmeter.
Apparatus The stimuli were mounted in Pleasant-Unpleasant, Pleasant-Neutral and Unpleasant-Neutral pairs on heavy black 14- X 40-in. cardboard strips and presented in the apparatus pictured in Fig. 1. The subjects were seated at a table on which was loca~eda large plywood box 38 in. long, 30 in. wide and 26 in. high. A 20-w neon light shielded so as to illuminate only the stimulus cards and a Beaulieu R-16 automatic movie camera equipped with an Angenieux 12 X 120/200-mm zoom lens were located inside the box. The subjects' heads were supported by a chin rest and restrained by an elastic strap at an aperture at the end of the box opposite the stand for the stimulus card. The camera was focused on the aperture. The stimuli were inserted into the box through a slit for 10-sec. exposure periods. Light for the photography was provided by a 500-w bulb beamed through Topies of the pictures are available upon request.
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a red filter. This technique permitted infrared photography of the eyes even though the interior of the box was dark except for the light focused on the stimuli. The camera was set to take exposures of the subjects' eyes at the rate of four frames per second. The number of exposures during which the subjects attended to each of the stimuli were counted. Exposures during which the subjects' eyes were closed or during which they were not clearly aligned with one stimulus or the other were not scored. Before the experiment began the subjects were shown the interior of the box and its workings were explained. The dependent variables consisted of the mean number of frames, per stimulus exposure, during which the subject attended to each type of picture. These means were termed "attention scores." Differences in attention to the three types of stimuli were compared across independent variable quartiles by F tests. Because it seemed possible that the predicted effects might appear only between extreme groups, mean differences in attention score between the first and fourth quartiles on each independent variable were also studied with t tests.
RESULTS The mean attention scores, Ps and ts are presented in Table 1. The results did not support the predictions. As can be seen from Table 1, none of the 18 Ps was significant at the .05 level. Nor were any of the 18 ts between the first and fourth quartiles on any of the Anhedonia or Sensation-seeking measures significant. These results suggest that selective attention to different types of stimuli is not a part of the emotional deficit process in schizophrenia. Metz ( 1961) found greater variability in the preferences of schizophrenic children for stimulation than he found in comparison groups of normal and autistic children. His findings suggest that selective attention to stimuli of differing emotional content may be particularly variable among highly anhedonic or low sensation-seeking subjects. To test this hypothesis, F,,, tests were also run on each of the dependent variables over the four quartile groups. Three of the 18 F,,, tests for variance differences were significant, suggesting that selective attention may play a role in emotional deficit. However, the differences in variances are difficult to interpret as they do not reflect consistent trends. The standard deviations for the first, second, third and fourth quartiles on Anhedonia for the pleasant stimuli were: 3.2, 4.9, 3.2, and 2.4 respectively
SCHIZOPHRENIC AFFECTIVE DEFICIT
TABLE 1 MEANATTENTION SCORE ( X 10) FOR PLEASANT, UNPLEASANT AND NEUTRAL STIMULI;P AND P ,., TESTFOR DIFFERENCES IN MEANSAND VARIANCES ACROSSALL QUARTILES, AND I TESTSFOR DIFFERENCES IN MEANS BETWEEN FIRSTAND FOURTH QuARTILES Criterion
Quartile
Test
Stimuli Pleasant Unoleasant Neutral
Anhedonia
General Sensation-seeking
Disinhibition
Boredom Susceptibility
(F,,,, = 4.08, dfs = 4 / 2 4 ) . For the unpleasant stimuli on General Sensationseeking they were: 5.2,2.9, 3.5, and 4.2 respectively ( P, = 3.26, dfs = 4/24), while the standard deviations for unpleasant stimuli on the four Experience= 4.05, dfs = seeking quartiles were: 5.3, 3.2, 2.6, and 4.5 respectively ( P,, 4 / 2 4 ) . Thus no specific variability trends for individuals with particularly
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high or low scores on any of these three independent variables were present. This state of affairs suggests chat the differences may reflect chance variations. The present results do not appear to complement the Metz findings.
DISCUSSION In the present study a search for differences in attention to various types of stimuli between individuals varying on sensation-seeking and Anhedonia scale scores was made. N o significant differences in tendency to attend to pleasant, unpleasant, or neutral stimuli appeared between groups varying on those dimensions. These results cast doubt on the theory that either of the two psychopathological emotional deficits represents an attempt to decrease exposure to either pleasant or unpleasant emotional stimuli through selective attention. The results, then, failed to provide information useful in explaining the low level of positive emotion in schizophrenics. These findings are, however, consistent with other research undertaken in our laboratory4 suggesting that thresholds for pleasant, unpleasant, and neutral srimuli are not correlated with Anhedonia scores but that anhedonia is related to the affective interpretations given ambiguous stimuli. These results tend to suggest that affective deficits are mediated by a neutral attitudinal set to stimuli which typically evokes positive emotions in normals. In view of the clinical importance of emotional deficits, additional research to clarify the nature of anhedonia is needed. REFERENCES BERLYNE,D. E Conflict, arousal and cusiosity. New York: McGraw-Hill. 1960. CHAPMAN,L. J., & CHAPMAN,J. P. Disordered thought in schizophrenia. New York: Appleton-Century-Crofts, 1973. KAYTON,L., & KOH, S. D. Hypohedonia in schizophrenia. lorrrnal o f Nervous and Mental Disease, 1975, 161, 412-420. MEEHL.P. E. Schizotaxia, schizotypy, schizophrenia. Aqne~ican Psychologijt, 1962, 17.827-838. METZ, J. 'R. Stimulation level preferences of autistic children. Journal of Abnormal Psychology, 1967, 7 2 , 529-535. RADO,S. Psychoanalysis o f behavior: collected papers. Vol. 2. New York: Grune & Stratton, 1962. WATSON,C G. Relationships of anhedonia to learning under various contingcncies. Jorrrnal o f Abnormal Psychology, 1972, 80, 43-48. ( a ) W'A'TSON, C. G. Relationships of anhedonia to physiological reactivity and threshold. Psychological Reports, 1972, 31, 43-46. ( b ) WATSON. C. G.. KLETT, W. G.. & LOREI, T. Toward an operational definition of anhedonia. Psychological Reports, 1970. 26, 371-376. WISE,C. D., & STEIN.L. Dopamine-8 hydcoxylase deficits in the brains of schizophrenic patients. Science, 1973, 181, 344-347. ZUCKERMAN, M. Dimensions of sensation seeking. Journal o f Consulting and Clinical Psychology, 1971. 36, 45-52. Accepted M a d J, 1976.
'C G. Watson. Anhedonia as a function of non-affective interpretation of ambiguous stimuli and threshold for affective and neutral stimuli. (Unpublished manuscript)
ROLE OF SELECTIVE AITENTION T O EMOTIONAL AND NEUTRAL STIMULI I N SCHIZOPHRENIC AFFECTIVE DEFICIT1 CHARLES G. WATSON AND LYLE JACOBS Veterans Administration Hospital, St. Cloud, Minnesota Sumrna~y.-A test of the hypothesis that psychopathological emotional deficit involves selective attention to unemotional stimuli was made. The attention of schizophrenics ( ? I = 100) with high and low scores on measures of anhedonia and sensation-seeking to pleasant, unpleasant and neutral stimuli was contrasted. N o differences in the mean attention scores of the groups appeared. The results do not support the hypothesis. Emotional deficit in schizophrenia does not seem to result from selective attention to nonemotional stimuli.
It appears that psychiatric patients suffer from two disrinct emotional deficits. The first, anhedonia, has been described by Rado (1962) as a low general level of motivation, and an inability to experience such positive emotions as joy, zest, pride, and desire. Watson and Jacobs (unpublished) have noted that it tends to be associated with schizophrenic psychopathology. The second deficit, reduced sensation-seeking, reflects a restricted interest in adventure, thrills and uninhibited behavior. Despite their conceptual similarity, the two deficits appear to be unrelated." Although these phenomena are well-known among clinicians, their etiologies in psychiatric patients are unclear. Rado (1962) has theorized that anhedonia is a largely genetic disorder which precipicates a variety of schizophrenic performance deficits by undermining the motivating strength of positive emotions such as joy, pride, desire, and zest. Meehl (1962) has further suggested that defects in those cencers in the brain which mediate positive reinforcements could create a predisposition to schizophrenic behavior by weakening the ability of positive reinforcers co suengthen socially appropriate behaviors, thus increasing the probability of interpersonal aversiveness, disordered thought, unconventional verbalizations and other schizophrenic tendencies. Research on anhedonia has been sparse. Kayton and Koh (1975) have found that the free recall of pleasanc words in schizophrenics is, in facr, poorer than that for nonschizophrenics and normal controls, even though their recall of unpleasant words was no different from that of the other two groups. Their work tends to document the presence of anhedonia in schizophrenics. Wise and Stein (1973) noted that the level of dopamine-P-hydroxylase enzyme in 'This study was supported by the Veterans Administration Medical Research Service. MRIS No. 0298-05. The authors are indebted to John Swenson, James Olson, Gail Bamber, Norbert Kollodge. William Daly, Bruce Watkins. Teresa Kucala, Helen Buerkle, and Kathy Mack for their contributions to the project Requests for reprints should be sent to Charles G. Watson, Research Service, Veterans Administration Hospital. St. Cloud, Minnesota 56301. 'C. G. Watson & L. Jacobs. Evidence for a dual-factor concept of psychopathological emotional deficit; anhedonia and sensation-seeking. (Unpublished manuscript)
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the brains of schizophrenics is deficient. Since this enzyme is involved in the mediation of reward, they suggested that it may be responsible for anhedonia and thus provide a physiological explanation for the phenomenon. By comparing the learning of high- and low-anhedonic schizophrenics under primary, secondary, and social rewards and punishments, Watson (1972a) tested the hypotheses that anhedonia ( a ) stems from specific physiological dysfunctions in pleasure-mediating centers and ( b ) represents no more than the aversion of some schizophrenics to other human beings. His results did not support either theory. To determine whether anhedonia is related to physiological arousal level, Watson ( 1972b) also studied the correlations between Anhedonia scores and pulse, blood pressure, and tremulousness under resting and stress conditions. None of the correlations was significant. Additionally, he found Anhedonia scores unrelated to electrical stimulation threshold. While not conclusive, these results tend to undermine the view that anhedonia is physiologically based. Other research has suggested that the sensation-seeking dimension may be relevant to emotional deficit. Sensation-seeking is typically (e.g., Berlyne, 1960) described as an internal need for stimulation which, when not met, leads to boredom and, thence, to the pursuit of adventure. While this construct has more often been invoked as an explanation for antisocial behavior and uninhibitedness, it seemed possible that the high autonomic responsiveness of schizophrenics and neurotics may lead to abnormally low sensation-seeking needs and, thus, to the low emotionality in these groups. However, the extent to which this formulation applies to schizophrenic and neurotic behavior is, as yet, unknown. Thus, the mechanisms behind psychopathological emotional deficit are essentially unknown at present. The present paper describes a study designed to test another hypothesis on the etiologies of anhedonia and sensation-seeking. In the formulation researched here, these defects in positive affect are viewed as defenses against the unpleasant effects of emotional arousal. One method of defending against arousal is selectively to attend to neutral, rather than emotional, stimuli when given the choice. To evaluate this formulation, the experimenters presented pairs of pleasant-neutral, unpleasant-neutral and pleasant-unpleasant visual stimuli to schizophrenics varying on anhedonia and sensation-seeking measures for 10-sec. periods. It was hypothesized that, when compared to their less anhedonic and/or more sensation-seeking counterparts, patients with high levels of these affectual defects would attend to the neutral stimuli for longer periods of time than they would the pleasant and unpleasant ones.
METHOD Subjects
The subjects were 100 male schizophrenics at the St. Cloud (Minnesota) Veterans Administration Hospital, a 1,002-bed psychiatric hospital. All were
SCHlZOPHRENIC AFFECTIVE DEFICIT
1005
volunteer subjects under the age of 60 in whose clinical files there was no evidence of brain damage. The mean age, education, total months of psychiatric hospitalization and SRA Tests of Educational Ability-based estimates (Watson & Klett, 1973) of Wechsler Adult Intelligence Scale IQ (and their standard deviations) of the 100 were: 35.6 yr. (10.8), 11.5 yr. (2.3), 43.5 mo. (@.0), and 102.1 ( 1 1.9). The means (and standard deviations) on the anhedonia and sensation-seeking variables were: Anhedonia Interview-12.5 (4.4); General Sensation-seeking-7.7 (3.9)'; Thrill and Adventure-seeking-6.6 (3.6); Experience-seeking-5.5 (3.6); Disinhibition--4.6 (2.7), and Boredom Susceptibility-5.2 (2.4). Quartile Matching The subjects were divided into quartiles on each of the six independent variables and the quartiles compared for mean attention time to pleasant, unpleasant and neutral stimuli in a procedure described below. Because of their possible effects as contaminants, the four quartile groups for each independent variable were first matched for mean age, education, length of hospitalization, and I Q estimates. The mean ages of the four Anhedonia quartiles were not significantly different from one another but the mean ages of the General Sensation-seeking, Thrill and Adventure-seeking, Experience-seeking, Disinhibition and Boredom Susceptibility scale quartiles either were significant or approached significance at the .05 level (Fs = 4.72, 4.02, 6.74, 4.08, and 1.99 respectively; all dfs = 3/96). In each case scores on the Sensation-seeking variables and age were negatively correlated. Additionally, the differences between the mean total months of psychiatric hospitalizations across quartiles for the Anhedonia, General Sensation-seeking and Experience-seeking scales were significant at the .20 level (Ps = 2.58, 1.78, and 1.69 respectively, dfs = 3/96), hospitalization tending to be positively correlated with affectual deficit. Moreover, the differences between the mean IQ estimates of the four Thrill and Adventure-seeking quartiles approached significance ( F = 1.79, dfs = 3/96, p < .20). N o differences approaching significance appeared on education. Matching for these demographic variables necessitated the removal of three, four, four, five, three, and one subject(s) respectively from each quartile in the analyses of Anhedonia, General Sensation-seeking, Thrill and Adventureseeking, Experience-seeking, Disinhibition, and Boredom Susceptibility respectively. After this had been achieved, no differences significant at the .20 level remained on any of the demographic variables. Thus, the number of subjects in each quartile varied between 20 and 24 in the six sets of analyses. Additional t tests were run to check for differences on mean age, length of hospitalization, education and estimated IQ between the first and fourth quarciles each of the Anhedonia and Sensation-seeking scales. None approached significance. Measures of Affective Deficit The independent measures used were the semi-structured Anhedonia Inter-
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view scale developed by Watson, Klett, and Lorei (1970) and Zuckerman's ( 1971 ) five Sensation-seeking scales. The former consists of five multi-point ratings dealing with lack of feeling, drive, hobbies and social interests, and avoidance of responsibility. Its internal consistency and test-retest reliability have been reported as .76 and .82 respectively (Watson, 1972a). The Sensation-seeking scales are factor-analytic self-report measures named General Sensation-seeking, Thrill and Adventure-seeking, Experience-seeking, Disinhibition, and Boredom Susceptibility. Their derivation and composition are described by Zuckerman (1971) in more detail.
Stimuli The subjects were exposed to sets of positive-, negative- and neutralcontent photographs taken from advertisements and feature stories in news magazines. One hundred and thirty-eight photos, deliberately chosen because they seemed (to the senior author) to have particularly pleasant, unpleasant or emotionless content, were clipped and presented to four judges (hospital employees naive as to the purpose of the project) with instructions to sort them into pleasant-, unpleasant- and neutral-content piles. Pictures which were not viewed by all four judges as falling into a particular category were eliminated. The judges were also instructed to rank-order the pictures within each pile for strength of positive, negative and nonemotional content. Those six pictures in each category which received the highest ratings were then tentatively defined as Positive-, Negative- and Neutral-stimulus content scales. The stimuli were presented to the subjects in pairs consisting of the most pleasantunpleasant, pleasant-neutral, and unpleasant-neutral pairs, the second most pleasant-unpleasant, pleasant-neutral and unpleasant-neutral pairs, etc. Thus each stimulus was presented twice to every subject. As Chapman and Chapman (1973) have noted, it is critically important that the reliability of dependent variables be matched in studies in which the performances of groups on several criteria are to be compared since failure to do so undermines the validity of across-criterion comparisons. Consequently, a pilot study was run to equate the sets of pleasant, unpleasant, and neutral stimuli for reliability. As is mentioned above, the stimuli consisted of 18 pairs of pleasant-unpleasant, pleasant-neutral and unpleasant-neutral stimuli, six in each combination. These 18 pairs were administered to 20 schizophrenic patients who were not subsequently employed in the main study. The amount of time during 10-sec. exposure intervals during which the subjects attended to the positive, negative and neutral stimuli in each of the 12 pairings was recorded. Attention time to each stimulus was considered as a response to a scale item and Hoyt alpha reliability coefficients were then calculated separately for the Positive, Negative, and Neutral sets of stimuli. The alphas-.42, . 5 5 , and .53 respectively-were quite low. In order to improve the reliability, all stimulus items whose correlations with their respective scale score totals were less than
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.30 were eliminated. This procedure produced Positive, Negative, and Neutral scales consisting of 8, 10, and 9 pictorial stimuli each. The alpha coefficients for the modified scales were more acceptable-Positive stimuli, .73; Negative stimuli, 1.59; and Neutral stimuli, .63 respectively. Moreover an F based on the ratio of the squares of the largest and smallest of these two correlations (P = 1.35, dfs = 19/19) fell far short of significance indicating that the reliabilities of the sets of stimuli did not differ significantly. Thus, it was assumed that differences between the scores of the groups on the three scales could be compared meaningfully. The positive pictures finally employed included five photographs-(a) two smiling baseball players jumping into the air, perhaps in celebration of a victory; ( b ) a pretty 5-yr.-old girl, her head cocked to one side, smiling into the camera; ( c ) a handsome young couple smiling and chatting by the sea; ( d ) a man and a semi-nude woman in a lusty embrace; and ( e ) an attractive young woman licking an ice cream cone. The negative stimuli were pictures of ( a ) the mutilated bodies of seven executed men squeezed into narrow wooden caskets; ( b ) a blood-spattered man being machine-gunned to death; ( c ) a soldier grimacing in pain as a serious wound is cleaned; ( d ) the bloody and bandaged face of a tired looking old woman; ( e ) the bullet-riddled, bloodied body of a man lying on a trash pile; and ( f ) a tearful woman leaving a casket at the conclusion of a funeral. The neutral stimuli included a picture of college students listening to a lecture, an expressionless old man, a bottle of inexpensive whiskey, and three pictures of expressionless middle-aged men. Another positive stimulus, that of a 3-yr.-old boy with his head thrown back in laughter, was eliminated during the process of matching for reliabilit~.~The magazine pictures were then photographed and reproduced as 8- X 11-in. black and white glossy prints. The prints were all equated for over-all brightness using a General Electric Type 213 footcandle lightmeter.
Apparatus The stimuli were mounted in Pleasant-Unpleasant, Pleasant-Neutral and Unpleasant-Neutral pairs on heavy black 14- X 40-in. cardboard strips and presented in the apparatus pictured in Fig. 1. The subjects were seated at a table on which was loca~eda large plywood box 38 in. long, 30 in. wide and 26 in. high. A 20-w neon light shielded so as to illuminate only the stimulus cards and a Beaulieu R-16 automatic movie camera equipped with an Angenieux 12 X 120/200-mm zoom lens were located inside the box. The subjects' heads were supported by a chin rest and restrained by an elastic strap at an aperture at the end of the box opposite the stand for the stimulus card. The camera was focused on the aperture. The stimuli were inserted into the box through a slit for 10-sec. exposure periods. Light for the photography was provided by a 500-w bulb beamed through Topies of the pictures are available upon request.
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a red filter. This technique permitted infrared photography of the eyes even though the interior of the box was dark except for the light focused on the stimuli. The camera was set to take exposures of the subjects' eyes at the rate of four frames per second. The number of exposures during which the subjects attended to each of the stimuli were counted. Exposures during which the subjects' eyes were closed or during which they were not clearly aligned with one stimulus or the other were not scored. Before the experiment began the subjects were shown the interior of the box and its workings were explained. The dependent variables consisted of the mean number of frames, per stimulus exposure, during which the subject attended to each type of picture. These means were termed "attention scores." Differences in attention to the three types of stimuli were compared across independent variable quartiles by F tests. Because it seemed possible that the predicted effects might appear only between extreme groups, mean differences in attention score between the first and fourth quartiles on each independent variable were also studied with t tests.
RESULTS The mean attention scores, Ps and ts are presented in Table 1. The results did not support the predictions. As can be seen from Table 1, none of the 18 Ps was significant at the .05 level. Nor were any of the 18 ts between the first and fourth quartiles on any of the Anhedonia or Sensation-seeking measures significant. These results suggest that selective attention to different types of stimuli is not a part of the emotional deficit process in schizophrenia. Metz ( 1961) found greater variability in the preferences of schizophrenic children for stimulation than he found in comparison groups of normal and autistic children. His findings suggest that selective attention to stimuli of differing emotional content may be particularly variable among highly anhedonic or low sensation-seeking subjects. To test this hypothesis, F,,, tests were also run on each of the dependent variables over the four quartile groups. Three of the 18 F,,, tests for variance differences were significant, suggesting that selective attention may play a role in emotional deficit. However, the differences in variances are difficult to interpret as they do not reflect consistent trends. The standard deviations for the first, second, third and fourth quartiles on Anhedonia for the pleasant stimuli were: 3.2, 4.9, 3.2, and 2.4 respectively
SCHIZOPHRENIC AFFECTIVE DEFICIT
TABLE 1 MEANATTENTION SCORE ( X 10) FOR PLEASANT, UNPLEASANT AND NEUTRAL STIMULI;P AND P ,., TESTFOR DIFFERENCES IN MEANSAND VARIANCES ACROSSALL QUARTILES, AND I TESTSFOR DIFFERENCES IN MEANS BETWEEN FIRSTAND FOURTH QuARTILES Criterion
Quartile
Test
Stimuli Pleasant Unoleasant Neutral
Anhedonia
General Sensation-seeking
Disinhibition
Boredom Susceptibility
(F,,,, = 4.08, dfs = 4 / 2 4 ) . For the unpleasant stimuli on General Sensationseeking they were: 5.2,2.9, 3.5, and 4.2 respectively ( P, = 3.26, dfs = 4/24), while the standard deviations for unpleasant stimuli on the four Experience= 4.05, dfs = seeking quartiles were: 5.3, 3.2, 2.6, and 4.5 respectively ( P,, 4 / 2 4 ) . Thus no specific variability trends for individuals with particularly
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high or low scores on any of these three independent variables were present. This state of affairs suggests chat the differences may reflect chance variations. The present results do not appear to complement the Metz findings.
DISCUSSION In the present study a search for differences in attention to various types of stimuli between individuals varying on sensation-seeking and Anhedonia scale scores was made. N o significant differences in tendency to attend to pleasant, unpleasant, or neutral stimuli appeared between groups varying on those dimensions. These results cast doubt on the theory that either of the two psychopathological emotional deficits represents an attempt to decrease exposure to either pleasant or unpleasant emotional stimuli through selective attention. The results, then, failed to provide information useful in explaining the low level of positive emotion in schizophrenics. These findings are, however, consistent with other research undertaken in our laboratory4 suggesting that thresholds for pleasant, unpleasant, and neutral srimuli are not correlated with Anhedonia scores but that anhedonia is related to the affective interpretations given ambiguous stimuli. These results tend to suggest that affective deficits are mediated by a neutral attitudinal set to stimuli which typically evokes positive emotions in normals. In view of the clinical importance of emotional deficits, additional research to clarify the nature of anhedonia is needed. REFERENCES BERLYNE,D. E Conflict, arousal and cusiosity. New York: McGraw-Hill. 1960. CHAPMAN,L. J., & CHAPMAN,J. P. Disordered thought in schizophrenia. New York: Appleton-Century-Crofts, 1973. KAYTON,L., & KOH, S. D. Hypohedonia in schizophrenia. lorrrnal o f Nervous and Mental Disease, 1975, 161, 412-420. MEEHL.P. E. Schizotaxia, schizotypy, schizophrenia. Aqne~ican Psychologijt, 1962, 17.827-838. METZ, J. 'R. Stimulation level preferences of autistic children. Journal of Abnormal Psychology, 1967, 7 2 , 529-535. RADO,S. Psychoanalysis o f behavior: collected papers. Vol. 2. New York: Grune & Stratton, 1962. WATSON,C G. Relationships of anhedonia to learning under various contingcncies. Jorrrnal o f Abnormal Psychology, 1972, 80, 43-48. ( a ) W'A'TSON, C. G. Relationships of anhedonia to physiological reactivity and threshold. Psychological Reports, 1972, 31, 43-46. ( b ) WATSON. C. G.. KLETT, W. G.. & LOREI, T. Toward an operational definition of anhedonia. Psychological Reports, 1970. 26, 371-376. WISE,C. D., & STEIN.L. Dopamine-8 hydcoxylase deficits in the brains of schizophrenic patients. Science, 1973, 181, 344-347. ZUCKERMAN, M. Dimensions of sensation seeking. Journal o f Consulting and Clinical Psychology, 1971. 36, 45-52. Accepted M a d J, 1976.
'C G. Watson. Anhedonia as a function of non-affective interpretation of ambiguous stimuli and threshold for affective and neutral stimuli. (Unpublished manuscript)
