Percefitzlal and Motor Skills, 1977,45, 1287-1290.
@ Perceptual and Motor Skills 1977
SEX DIFFERENCES I N CLERICAL SPEED: PERCEPTUAL SPEED VERSUS COMPARISON AND DECISION SPEED1 RAYMOND L. MAJERES Western Illinois University Szlmmary.-The hypothesis that sex differences in clerical speed are based on differences in perceptual speed was tested in an experiment using tachistoscopic presentation of pairs of items requiring same-different judgments. This procedure eliminated the attentional shifts from item to item as well as the repetitive nature of the task. 10 females still were signiifcantly faster than 10 males. Also no significant sex differences were found in an additional visual search task requiring rapid recognition and shifts in attention. Results were interpreted in terms of sex differences in comparison and decision time as opposed to perceptual speed.
Females have been found to be faster than males on tests of clerical speed (Anastasi, 1958; Fairweather, 1976; Tyler, 1965). These tests involve the rapid and sequential recognition of similarities and differences between sets of digits or letters, e.g., 47635-46735, and are frequently referred to as measures of perceptual speed. Although the understanding of sex differences in cognitive abilities is of general interest, a major contribution of such studies is in furthering the understanding of the interplay between biological and environmental variables in the development of human abilities. Such an understanding depends on an accurate description of the cognitive processes underlying these sex differences. Most interpretations of the sex difference on clerical speed tests have emphasized a difference in rapid recognition and in efficiency of attentional shifts (Anastasi, 1958; Tyler, 1965) since subjects must compare items presented in lengthy lists and indicate whether pair members are the same or different. However, Guilford ( 1967) has interpreted the clerical speed tests as measuring comparison and decision processes as opposed to recognition and attentional shifts. Also Broverman, Klaiber, Kobayashi, and Vogel ( 1968) have hypothesized that sex differences on clerical speed tests and similar tasks are dependent upon the repetitive (making rapid consecutive judgments) and overlearned nature of these tasks. The purpose of the present experiment was to test the interpretation of perceptual speed as the basis for the sex difference on the clerical speed tests and also to test the hypothesis that the repetitive nature of these tests is essential for observing the sex difference. In the present experiment subjects were required to compare pairs of lThis research was supported by a grant from the Western Illinois University Research Council. Requests for reprints should be sent to Raymond L. Majeres, Department of Psychology, Western Illinois University, Macomb, Illinois 61455.
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stimulus items when these items were tachistoscopically presented one pair at a time. Presumably, if comparison and decision time is critical for observing the sex difference, then a significant sex difference should be observed during the presentation of single pairs. Subjects also were given similar items in lists, the standard clerical speed test format. This was done to determine whether previously observed sex differences could be reliably found in the present population and also to determine whether performance under the two conditions, single-pair versus list presentation, was correlated. Presumably, if comparison and decision processes are the major contributors to the sex difference, not only should there be significant sex differences under both conditions, but performance on the two tasks should be significantly correlated.
METHOD Sabjects College-student volunteers, 10 males and 10 females, from introductory psychology classes at a midwestern state university participated in the study for course credit. Procedares Ten pairs of seven-digit numbers and 10 pairs of seven-letter nonsense words (.9 cm high and 3.5 cm apart) similar to those in the Minnesota Clerical Test (Andrew & Paterson, 1946) were presented individually using a tachistoscope. Each pair was presented for 500 msec. and subjects were to respond "same" or "different." Twenty percent were, in fact, different. Half of the subjects received the digit-pairs first and then the letter-pairs, with the other half of the subjects getting the reverse order. Each pair was presented twice in a random order with an interstimulus interval of about 15 sec. A digital clock started with the presentarion of the pair and was stopped by the subject's vocal response using a voice-key relay. In addition, 50 pairs of seven-digit numbers and also a similar list of pairs of seven-letter nonsense words were presented to all subjects. Half of the subjects received the numbers first and half received the words first. The lists were typed on 8%-in. X 11-in. sheets. The sheet was placed before each subject and adjusted to his usual writing position. Subjects were asked to judge whether the members of each pair were the same or different and, with a pencil, place a check mark beside those that did not match. Again 20% were actually different. For all subjects the presentation of single items preceded the presentation of the lists.
RESULTS Single-pair presentation A 2 X 2 X 2 analysis of variance of the data for presentation of single
SEX DIFFERENCES IN CLERICAL SPEED
1289
pairs with sex as a between-subjects variable and stimulus conditions and trials as within-subjects variables yielded a significant main effect of sex (F1,18 = 4.25, p < .05, MS, = 5.01 ) . Females were faster than males under conditions of discrete presentation (Ms = 1.95 sec. and 2.45 sec., respectively; SDs = .47 and .GO). Effects of trials (Fl,ls = 11.49, p < .005) and the interaction of stimulus X trials (Fl,ls = 8.29, p < .01) were also significant. There was greater improvement from Trial 1 to Trial 2 for letter pairs than for digit pairs. This was the case for both males and females.
List Presentation A 2 X 2 analysis of variance of total times on the 50-item list with sex and stimulus conditions (a within-subjects variable) as factors indicated that under the conditions of list presentation, the standard clerical speed-test condition, there was a significant sex difference (F1,18 = 13.72, p < .002, MSe = 16100.69), with females faster than males (Ms = 110.7 sec. and 150.7 sec., SDs = 26.4 and 21.3 respectively). The interaction of sex X stimulus conditions was not significant (F1,18 = 3.25, p < .08) but there was a tendency for the sex difference to be greater for letters than for digits, differences were 46.4 and 33.8, respectively. Matching times for digits, for both males and females, were significantly faster than for letters (FITls = 9.41, p < .01). The correlations between list versus single-pair presentation were .61 (df = 18, p < .01) for letters and .69 (df = 18, p < -001) for digits.
DISCUSSION Even though the present task required comparisons between pairs of stimulus items with the necessity for attentional shifts eliminated, significant sex differences were still found. This result suggests that sich differences as observed on the clerical speed tests are not solely due to differences in recognition speed or attentional shifts as frequently claimed. Also, when the same subjects were given a clerical speed test, there were large and significant correlations between performance times on the two tasks. The implication of this finding is that the comparison and decision process may itself be an important source of the sex difference. As a further test of the perceptual speed as the explanation of the sex difference on the clerical speed test, 24 males and 24 females were given a visual search task which required them to recognize rapidly the presence of a recurring target item in a list, e.g., the word " r e d in a list of color names. Subjects were required to move from left to right and down rows of items searching for and making a tapping response to all instances of an experimenter designated target item. There were four lists: color patches, color names, shapes, and shape names. All subjects were told the target item at the beginning of each trial. Each time they encountered the target item they were to tap a metal plate with
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a stylus. The number of taps was automatically recorded and was used as a measure of accuracy. Subjects were instructed to scan the lists from left to right and down as rapidly and as accurately as possible. Each of the four lists was searched a total of nine times. Errors were too infrequent for a meaningful analysis. The dependent variable was the time to search each list and was recorded using a stopwatch. The mean times for males and females were 6.82 sec. and 5.59 sec., respectively. Although females did tend to be faster than males, this difference was not significant (F1,22 = 1.96, 1) = .17, MSe = 108.44). This was the case despite the fact that samples were larger than in the first experiment and the number of individual comparisons (total items processed) was much greater ( 1,140 versus only 20 tachistoscopic comparisons). Bearing in mind that comparison (with an item in memory) and decision time are to some extent involved in the visual search task, there appears to be little compelling evidence that the sex difference on the clerical speed tests is the result of sex differences in perceptual recognition or in attentional shifts or that the repetitive aspect is important. The present results suggest that previous characterizations of the sex difference on clerical speed tests as due to a difference in perceptual speed are not well founded. Rapid recognition and the ability to shift attention under speeded repetitive conditions may be important factors in performance on the clerical speed tests, but it is doubtful that they are the source of the sex difference on these tests. Rather, as Guilford (1967) has hypothesized, the sex difference appears to be more clearly related to comparison and decision processes or what Guilford refers to as the evaluation operation. The present findings are consistent with such an interpretation. REFERENCES ANASTASI,A. Differential psychology. ( 3rd ed. ) New York: Macmillan, 1958. ANDREW,D. M., & PATERSON,D. G. Minnesota Clerical Test: manzlal. New York: Psychological Corp., 1946. BROVERMAN, D. M., KLAIBER,E. L., KOBAYASHI, Y., & VOGEL,W. Roles of activation and inhibition in sex differences in cognitive abilities. Psychological Review, 1968, 75, 23-50. FAIRWEATHER, H. Sex differences in cognition. Cognition, 1976, 4, 231-280. GUILPORD,J. P. The nature of human intelligence. New York: McGraw-Hill, 1967. TYLER,L. E. Psychology of h a m n differemces. New York: Appleton-Century-Crofts, 1965. Accepted November 8, 1977.
@ Perceptual and Motor Skills 1977
SEX DIFFERENCES I N CLERICAL SPEED: PERCEPTUAL SPEED VERSUS COMPARISON AND DECISION SPEED1 RAYMOND L. MAJERES Western Illinois University Szlmmary.-The hypothesis that sex differences in clerical speed are based on differences in perceptual speed was tested in an experiment using tachistoscopic presentation of pairs of items requiring same-different judgments. This procedure eliminated the attentional shifts from item to item as well as the repetitive nature of the task. 10 females still were signiifcantly faster than 10 males. Also no significant sex differences were found in an additional visual search task requiring rapid recognition and shifts in attention. Results were interpreted in terms of sex differences in comparison and decision time as opposed to perceptual speed.
Females have been found to be faster than males on tests of clerical speed (Anastasi, 1958; Fairweather, 1976; Tyler, 1965). These tests involve the rapid and sequential recognition of similarities and differences between sets of digits or letters, e.g., 47635-46735, and are frequently referred to as measures of perceptual speed. Although the understanding of sex differences in cognitive abilities is of general interest, a major contribution of such studies is in furthering the understanding of the interplay between biological and environmental variables in the development of human abilities. Such an understanding depends on an accurate description of the cognitive processes underlying these sex differences. Most interpretations of the sex difference on clerical speed tests have emphasized a difference in rapid recognition and in efficiency of attentional shifts (Anastasi, 1958; Tyler, 1965) since subjects must compare items presented in lengthy lists and indicate whether pair members are the same or different. However, Guilford ( 1967) has interpreted the clerical speed tests as measuring comparison and decision processes as opposed to recognition and attentional shifts. Also Broverman, Klaiber, Kobayashi, and Vogel ( 1968) have hypothesized that sex differences on clerical speed tests and similar tasks are dependent upon the repetitive (making rapid consecutive judgments) and overlearned nature of these tasks. The purpose of the present experiment was to test the interpretation of perceptual speed as the basis for the sex difference on the clerical speed tests and also to test the hypothesis that the repetitive nature of these tests is essential for observing the sex difference. In the present experiment subjects were required to compare pairs of lThis research was supported by a grant from the Western Illinois University Research Council. Requests for reprints should be sent to Raymond L. Majeres, Department of Psychology, Western Illinois University, Macomb, Illinois 61455.
1288
R. L. MAJERES
stimulus items when these items were tachistoscopically presented one pair at a time. Presumably, if comparison and decision time is critical for observing the sex difference, then a significant sex difference should be observed during the presentation of single pairs. Subjects also were given similar items in lists, the standard clerical speed test format. This was done to determine whether previously observed sex differences could be reliably found in the present population and also to determine whether performance under the two conditions, single-pair versus list presentation, was correlated. Presumably, if comparison and decision processes are the major contributors to the sex difference, not only should there be significant sex differences under both conditions, but performance on the two tasks should be significantly correlated.
METHOD Sabjects College-student volunteers, 10 males and 10 females, from introductory psychology classes at a midwestern state university participated in the study for course credit. Procedares Ten pairs of seven-digit numbers and 10 pairs of seven-letter nonsense words (.9 cm high and 3.5 cm apart) similar to those in the Minnesota Clerical Test (Andrew & Paterson, 1946) were presented individually using a tachistoscope. Each pair was presented for 500 msec. and subjects were to respond "same" or "different." Twenty percent were, in fact, different. Half of the subjects received the digit-pairs first and then the letter-pairs, with the other half of the subjects getting the reverse order. Each pair was presented twice in a random order with an interstimulus interval of about 15 sec. A digital clock started with the presentarion of the pair and was stopped by the subject's vocal response using a voice-key relay. In addition, 50 pairs of seven-digit numbers and also a similar list of pairs of seven-letter nonsense words were presented to all subjects. Half of the subjects received the numbers first and half received the words first. The lists were typed on 8%-in. X 11-in. sheets. The sheet was placed before each subject and adjusted to his usual writing position. Subjects were asked to judge whether the members of each pair were the same or different and, with a pencil, place a check mark beside those that did not match. Again 20% were actually different. For all subjects the presentation of single items preceded the presentation of the lists.
RESULTS Single-pair presentation A 2 X 2 X 2 analysis of variance of the data for presentation of single
SEX DIFFERENCES IN CLERICAL SPEED
1289
pairs with sex as a between-subjects variable and stimulus conditions and trials as within-subjects variables yielded a significant main effect of sex (F1,18 = 4.25, p < .05, MS, = 5.01 ) . Females were faster than males under conditions of discrete presentation (Ms = 1.95 sec. and 2.45 sec., respectively; SDs = .47 and .GO). Effects of trials (Fl,ls = 11.49, p < .005) and the interaction of stimulus X trials (Fl,ls = 8.29, p < .01) were also significant. There was greater improvement from Trial 1 to Trial 2 for letter pairs than for digit pairs. This was the case for both males and females.
List Presentation A 2 X 2 analysis of variance of total times on the 50-item list with sex and stimulus conditions (a within-subjects variable) as factors indicated that under the conditions of list presentation, the standard clerical speed-test condition, there was a significant sex difference (F1,18 = 13.72, p < .002, MSe = 16100.69), with females faster than males (Ms = 110.7 sec. and 150.7 sec., SDs = 26.4 and 21.3 respectively). The interaction of sex X stimulus conditions was not significant (F1,18 = 3.25, p < .08) but there was a tendency for the sex difference to be greater for letters than for digits, differences were 46.4 and 33.8, respectively. Matching times for digits, for both males and females, were significantly faster than for letters (FITls = 9.41, p < .01). The correlations between list versus single-pair presentation were .61 (df = 18, p < .01) for letters and .69 (df = 18, p < -001) for digits.
DISCUSSION Even though the present task required comparisons between pairs of stimulus items with the necessity for attentional shifts eliminated, significant sex differences were still found. This result suggests that sich differences as observed on the clerical speed tests are not solely due to differences in recognition speed or attentional shifts as frequently claimed. Also, when the same subjects were given a clerical speed test, there were large and significant correlations between performance times on the two tasks. The implication of this finding is that the comparison and decision process may itself be an important source of the sex difference. As a further test of the perceptual speed as the explanation of the sex difference on the clerical speed test, 24 males and 24 females were given a visual search task which required them to recognize rapidly the presence of a recurring target item in a list, e.g., the word " r e d in a list of color names. Subjects were required to move from left to right and down rows of items searching for and making a tapping response to all instances of an experimenter designated target item. There were four lists: color patches, color names, shapes, and shape names. All subjects were told the target item at the beginning of each trial. Each time they encountered the target item they were to tap a metal plate with
1230
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a stylus. The number of taps was automatically recorded and was used as a measure of accuracy. Subjects were instructed to scan the lists from left to right and down as rapidly and as accurately as possible. Each of the four lists was searched a total of nine times. Errors were too infrequent for a meaningful analysis. The dependent variable was the time to search each list and was recorded using a stopwatch. The mean times for males and females were 6.82 sec. and 5.59 sec., respectively. Although females did tend to be faster than males, this difference was not significant (F1,22 = 1.96, 1) = .17, MSe = 108.44). This was the case despite the fact that samples were larger than in the first experiment and the number of individual comparisons (total items processed) was much greater ( 1,140 versus only 20 tachistoscopic comparisons). Bearing in mind that comparison (with an item in memory) and decision time are to some extent involved in the visual search task, there appears to be little compelling evidence that the sex difference on the clerical speed tests is the result of sex differences in perceptual recognition or in attentional shifts or that the repetitive aspect is important. The present results suggest that previous characterizations of the sex difference on clerical speed tests as due to a difference in perceptual speed are not well founded. Rapid recognition and the ability to shift attention under speeded repetitive conditions may be important factors in performance on the clerical speed tests, but it is doubtful that they are the source of the sex difference on these tests. Rather, as Guilford (1967) has hypothesized, the sex difference appears to be more clearly related to comparison and decision processes or what Guilford refers to as the evaluation operation. The present findings are consistent with such an interpretation. REFERENCES ANASTASI,A. Differential psychology. ( 3rd ed. ) New York: Macmillan, 1958. ANDREW,D. M., & PATERSON,D. G. Minnesota Clerical Test: manzlal. New York: Psychological Corp., 1946. BROVERMAN, D. M., KLAIBER,E. L., KOBAYASHI, Y., & VOGEL,W. Roles of activation and inhibition in sex differences in cognitive abilities. Psychological Review, 1968, 75, 23-50. FAIRWEATHER, H. Sex differences in cognition. Cognition, 1976, 4, 231-280. GUILPORD,J. P. The nature of human intelligence. New York: McGraw-Hill, 1967. TYLER,L. E. Psychology of h a m n differemces. New York: Appleton-Century-Crofts, 1965. Accepted November 8, 1977.
