The Effect of Gender Differences in Hemispheric Asymmetry on Judgement

Joan Meyers-Levy, UCLA
ABSTRACT - Research suggests that males' cortical hemispheres are more specialized than are those of females. Theorizing derived from this observation led to several hypotheses. Qualitative differences in the outcomes of males' but not females' performance on a sorting task were anticipated when stimuli were presented in picture-form, which encouraged the use of right hemisphere processing, versus word form, which encouraged the use of the left hemisphere. Data are offered that support this prediction.
[ to cite ]:
Joan Meyers-Levy (1987) ,"The Effect of Gender Differences in Hemispheric Asymmetry on Judgement", in NA - Advances in Consumer Research Volume 14, eds. Melanie Wallendorf and Paul Anderson, Provo, UT : Association for Consumer Research, Pages: 51-53.

Advances in Consumer Research Volume 14, 1987      Pages 51-53

THE EFFECT OF GENDER DIFFERENCES IN HEMISPHERIC ASYMMETRY ON JUDGEMENT

Joan Meyers-Levy, UCLA

ABSTRACT -

Research suggests that males' cortical hemispheres are more specialized than are those of females. Theorizing derived from this observation led to several hypotheses. Qualitative differences in the outcomes of males' but not females' performance on a sorting task were anticipated when stimuli were presented in picture-form, which encouraged the use of right hemisphere processing, versus word form, which encouraged the use of the left hemisphere. Data are offered that support this prediction.

INTRODUCTION

A burgeoning literature suggests that gender differences exist in a broad assortment of judgments and behaviors (Eagly and Carli 1981; Lenney 1977; Meyers-Levy 1985). Recent research also seems to suggest that such gender differences may be related to differences in males' and females' cortical structure and functioning (McGlone 1980). Although at present these gender differences in cortical operation admittedly are equivocal and not clearly understood (see commentary to McGlone 1980), the current research attempts to explore the validity of some implications derived from current theorizing pertaining to gender differences in cortical operation. At issue is how the postulated gender differences in cortical operation might result in differences in males' and females' perceptions of objects or products.

HEMISPHERIC OPERATIONS AND GENDER DIFFERENCES

Before considering the issue of Bender differences in cortical functioning, a fundamental understanding of hemispheric specialization is necessary. Substantial research indicates that for most normal individuals qualitative differences exist in the type of processing performed by the right and left cortical hemispheres. The right hemisphere is typically associated with holistic or gestalt apprehension of information (Nebes 1978). This hemisphere seems to be more adept at perceiving whole configurations and relating stimulus elements into perceptual units rather than attending to the particulars and peculiarities embodied within the stimulus information (Bradshaw and Nettleton 1981). Accordingly, one might think of the right hemisphere as involved in a form of heuristic processing that often results in somewhat global and simplified perceptions. By contrast, the left hemisphere operates in a more analytic manner (Levy 1969). It is more adept at producing "a differentiation of the stimulus array into specific elements," (Tucker and Williamson 1984, p. 205). Thus, the left hemisphere appears to disaggregate stimuli and exhibit sensitivity to fine distinctions that occur among constituent elements of stimuli.

The right and left cortical hemispheres also seem to be implicated in the performance of certain types of tasks. The right hemisphere is implicated in the processing of nonlinguistic pictorial stimuli and most visual spatial processing (Bradshaw and Nettleton 1981). Tasks or stimuli of these sorts would see to benefit from the right hemisphere's capacity to appreciate holistic and synthetic aspects of stimuli. The left hemisphere is typically involved in comprehending the nuances of verbal or linguistic information. Thus, for example, the left hemisphere is involved in reading and speech production of words or sentences, which would seem to require substantial attention to and manipulation of subtle detail (e.g. attending to syntax, phonetics, etc.) and thereby be consistent with the left hemisphere's penchant for segmentation and apprehension of detail.

Investigations of gender differences in cortical functioning imply that these distinctions between how the right and left cerebral hemispheres operate are more pronounced among males than among females. Males' cortical hemispheres appear to be organized more asymmetrically relative to the hemispheres of females (McGlone 1980). Thus, males' hemispheres seem to be more specialized in their functional capacity, and in turn, males' performance of tasks tends to be rather exclusively tied to the activation of a single and particular ("appropriate") hemisphere. By contrast, females' hemispheres are organized more symmetrically. Females seem to use the right and left hemispheres more interchangeably. For example, in performing a visual spatial task, which is typically regarded as a right hemisphere task, research indicates that males are fount to consistently activate right hemisphere resources while females often engage in substantial left hemisphere activation during such task performance (Restak. 1979).

The discussion that follows draws upon this view of the genders' hemispheric organization and functioning. Implications are considered concerning how gender differences in the degree of hemispheric specialization of function might affect males' and females' perceptions of objects. The hypotheses that eventuate are then examined in an experimental study.

HYPOTHESES

The view that males' cortical hemispheres are more specialized than are those of females implies that males are more likely to selectively activate either the right or left hemisphere in processing information. Research suggests that the choice of which hemisphere is employed is likely to be a function of factors such as the pictorial or verbal nature of the stimuli (Hansen 1981) and the type of task to be performed (Bradshaw and Nettleton 1981). This suggests that if task-relevant stimuli were presented in either word or pictorial form, this manipulation would have a more pronounced or powerful impact in shaping males' as opposed to females' processing of the task information.

Consider a situation in which subjects are asked to sort each of several objects into groups that contain what subjects perceive as similar objects. Further, imagine that the objects to be sorted vary in how well they exemplify a particular product category (e.g. furniture). Thus, some objects are relatively good exemplars of the category (e.g. chair, stereo) while others are quite poor exemplars (e.g. fan, telephone). It would seem that performance of this sorting task could be accomplished by drawing upon either the right hemisphere, the left hemisphere, or both hemispheres. However, suppose that the form in which the category exemplars are presented is varied. For some subjects exemplars are presented in word form, while for other subjects exemplars are presented in picture form. There is reason to expect that this manipulation of the form in which stimulus materials are presented will differentially affect the genders' perceptions of the category exemplars.

Because it has been fount that males' hemispheres are relatively asymmetrically organized, thereby leading males to draw selectively and rather exclusively upon either right or left hemispheric resources, it is hypothesized that when task stimuli are presented in picture form, which typically invokes right hemisphere processing, males are more likely to activate exclusively right hemisphere resources. However, when stimuli are presented in word form, which typically stimulates left hemisphere processing, males are expected to activate exclusively left hemisphere resources. In turn, the outcomes observed on males' performance of the sorting task would be expected to distinctly reflect males' use of either the right or left hemisphere during task performance. Thus, the nature of males' performance in the sorting task can serve as a means of detecting which hemisphere they employ.

Males' use of the right or the left hemisphere in sorting stimulus items should produce qualitatively different outcomes. To the extent that right hemisphere resources are predominately employed in performing the sorting task, one would expect that the poor and relatively atypical category exemplars would be sorted in a holistic undifferentiated manner: though poor items would likely be perceived as less representative of the product category than would other stimulus items that better fit the category, poor exemplars would not be distinguished from one another. Thus, few groups should be formed among these poor exemplars. By contrast, if the task was performed by drawing on left hemisphere resources, one would expect greater distinctions or discriminations to be drawn among the poor exemplars. As a result, a relatively large number of groups should be formed among the poor exemplars. Moreover, poor exemplars often might be relegated to single-item groups that maximally distinguish these poor items from all other category exemplars.

Predictions for females, however, would be different. Because females' hemispheric organization is relatively symmetrical, it follows that females tend to use their cortical hemispheres more interchangeably and perhaps more simultaneously. Thus, the picture/word form manipulation of stimulus presentation should be less powerful in determining which of the two cortical hemispheres females employ during task performance. Instead, regardless of the form of stimulus presentation, females are likely to activate both rather than only a single hemisphere in performing the sorting task. This suggests that the sorting task outcomes displayed by females will reflect the use of both hemispheres. Accordingly, it would be anticipated that sorting task outcomes observed among females would be less extreme relative to those observed among males: Poor category exemplars should be sorted into a moderate number of groups, regardless of the picture/word form of stimulus presentation.

To summarize, an interaction between gender and the form of stimulus presentation is anticipated for the number of groups formed among the poor category exemplars and possibly the number of poor exemplars assigned to single-item groups containing solitary poor exemplars. More specifically, it is predicted that males' sorting behavior with respect to poor category exemplars will quite clearly reflect the use of the hemisphere associated with the processing of picture/word stimuli. Thus, males will form few groups from the poor category exemplars and form few single-item groups from these items when right hemisphere stimulus processing is encouraged by pictorial presentation of the stimulus materials. Poor category exemplars will be sorted into more groups and more single-item groups will be formed among these poor exemplars when left hemisphere processing is encouraged by word presentation of the stimulus materials. However, females' sorting behavior should be less affected by the pictorial/word form of stimulus presentation. Regardless of whether stimuli are presented in picture or word form, females are expected to employ both hemispheres in performing the sorting task. Thus, females are anticipated to assign poor category exemplars to an overall moderate number of groups and a moderate number of groups that contain only a single poor exemplar.

METHODOLOGY

Subjects

Thirty nine males and 39 female; from a middle class Midwestern community were recruited by a market research firm to participate as subjects. Each individual received $5 in return for his/her participation.

Procedure

Subjects were informed that the purpose of the study was to examine the types of objects that consumers perceive to be related. Subjects were asked to engage in a sorting task1. A detailed example of how this task was to be performed was provided to subjects. This example employed exemplars from an object category unrelated to the stimulus materials. Following this, subjects were presented with an array of 12 exemplars of a product category displayed on a single piece of paper. These exemplars were presented in either picture or word form. They consisted of four poor, four moderate, and four good exemplars of the object category (according to norms established by Rosch 1975) and were presented in random order. Subjects were instructed to sort these exemplars into groups that were to be comprised of items that subjects' perceived to be similar. Subjects were informed that they could form as many or as few groups as they desired, and groups could include as many or as few items as they deemed appropriate. After completing this task for exemplars associated with one object or product category (furniture), subjects performed the sane task for a second category (vehicles).

RESULTS

The data were analyzed as a 2 (gender) by 2 (presentation form: words, pictures) by 2 (hemisphere prime: right, left) factorial design. [Before performing this task, however, subjects were asked to perform a priming task. This task entailed having subjects perform either a visual spatial task or a verbal task. Because the sorting task performance data presented herein reveal no effects due to this manipulation, this priming task manipulation is not discussed further except for its inclusion as a factor in the data analyses. Also not discussed is a judgment task that subjects performed prior to the sorting task.] First, the number of groups formed among the poor category exemplars was analyzed for both object/product categories (furniture and vehicle). Multivariate analysis of these measures revealed the anticipated gender by presentation form interaction (F(2.67)-3.97, p<.02). Treatment means are presented in Table 1. Simple effect tests revealed that as expected males' but not females' performance was affected by the form in which category exemplars were presented. Males' assigned the poor exemplars to few r groups when exemplars were presented in picture rather than word form (F(1,68)-7.54, p<.01). However, females sorted the poor exemplars into a moderate and equivalent number of groups, regardless of whether exemplars were presented in picture or word form (F<1. As a result, males sorted the poor exemplars into somewhat fever groups than did females when exemplars were presented in picture form (P(1,68)=3.23, p<.08) but they sorted the poor exemplars into more groups than did females when the exemplars were presented in word form (F(1,68)-5.04, p< .03)

Analysis of the number of poor category exemplars that were assigned to groups consisting of only a single poor exemplar and no other items revealed main effects for gender (F(2,67)-4.74, p<.01) and presentation form (F(2,67)-4.62, p<.01). Males formed more single-item groups among the poor exemplars than did females (M-.91 versus M-.21, respectively), and more such single-item groups were formed when exemplars were presented in word than in picture form (M=1.43 versus M-.72). No interaction was observed among these variables.

TABLE 1

MANOVA CENTROIDS FOR SORTING MEASURES

DISCUSSION AND CONCLUSION

The data from this study are consistent with hypotheses derived from the view that males' cortical hemispheres are asymmetrically organized while those of females are relatively symmetrical in their organization. Because males' cortical hemispheres are relatively asymmetrically organized, males tend to selectively draw on either right or left hemisphere resources: Thus, it was hypothesized that the cortical hemisphere that males employed in processing the stimulus materials would vary depending upon whether stimulus materials were presented in pictorial form, which should encourage the use of the right hemisphere, or word form, which should encourage the use of the left hemisphere. The hemisphere used by males was detected by examining the nature of their performance on a sorting task. Consistent with predictions, when stimulus material was presented in picture form, males seemed to invoke right hemisphere resources in perceiving the stimuli. This was evidenced by their formation of few groups among the poor category exemplars. By contrast, males who were exposed to stimulus materials that were presented in word form seemed to draw upon left hemisphere resources in performing the sorting task. This was evidenced by their propensity to produce relatively differentiated groups among the poor exemplars. Thus, they formed a relatively large number of groups among the poor exemplars. Although a greater number of poor exemplars were assigned to single-item groups when stimulus materials were presented in word rather than picture form and males formed more such single-item groups than did females, the expectation that males would form more such groups when stimulus presentation was in word rather than picture form was not confirmed.

The data are also consistent with the hypothesis that females, whose cortices are relatively symmetrically organized, are less tied to the use of a particular hemisphere in processing information and in turn often use both hemispheres concurrently, regardless of the manner in which the stimulus materials are presented. In the present study this was exemplified by females' performance on the sorting task, which represented a balance between the unitization emphasis of the right hemisphere and the differentiation focus of the left hemisphere. Females formed a moderate number of groups among the poor category exemplars.

These findings have implications of potential interest to marketers. They lead to the inference that when targeting males, it may be possible to portray a product as more or less similar to a related though not necessarily most common product category associated with the focal product by varying whether the advertisement used to make this claim is predominately pictorial or verbal in its presentation form. If a marketer wishes to position his/her product as a member of a product category not normally associated with the focal product (e.g. positioning 7-Up as a soft drink), this might be better accomplished by labeling the product as a member of the product category and pictorially portraying the product with other members of this product category as opposed to discussing this relationship in a verbal message. Alternatively, if a marketer desires to position a product as different from other members in a product category, this would seem to be more effectively accomplished by verbally discussing how the product is distinguished from other members of the product category rather than relying on visual demonstration in discriminating the product from other category members. Research that explores these hypotheses in a more applied setting is needed.

REFERENCES

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Eagly, Alice H. and Carli, Linda L. (1981), "Sex of Researchers and Sex-Typed Communications as Determinants of Sex Differences on Influenceability: A Meta-Analysis of Social Influence Studies," Psychological Bulletin, 90 (July), 1-20.

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McGlone, Jeannette (1980), "Sex Differences in Human Brain Asymmetry: A Critical Survey," The Behavioral and Brain Sciences, 3 (June), 215-263.

Meyers-Levy, Joan (1985), "Gender Differences in Information Processing: A Selectivity Interpretation." Unpublished doctoral dissertation, Northwestern University.

Nebes, Robert D. (1978), "Direct Examination of Cognitive Function in the Right and Left Hemispheres." In Asymmetrical Function of the Brain, ed. M. Kinsbourne, Cambridge University Press.

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