At first glance, it would seem that finding a gender difference in the ways in which men and women experience and express emotion would be easy. In American culture, women are generally considered to be more emotional and more emotionally expressive than men. However, the research on this topic is mixed. For instance, when using self report data that asks respondents to assess their global emotional expressiveness and experience, different patterns of results are found than when using immediate assessment of emotion following an emotion-eliciting event. In one self-report study assessing respondents across twenty-six countries, women rated themselves to be more verbally expressive than males (Pennebaker, Rime and Blankenship, 1996). When self reports of the range of feelings people experience are obtained, women report both more intense emotions and a wider range of emotions (Copeland, Hwang, and Brody, 1996; Scherer, Wallbott and Summerfield, 1986).

One other way to obtain information on the quality of emotions is to use an established scale. One scale that has been used is the Affect Intensity Measure. On this scale, women report expressing more intense emotions than men (Diener, Sandvik, and Larsen, 1985; Barrett et al., 1998). However, it is important to note that the negative emotions that this scale measures do not include anger, but do emphasize anxiety. When specific emotions are examined rather than global emotionality, differences also emerge. Women often report more fear than men (Allen and Haccoun, 1976; Blier and Blier-Wilson, 1989; Brody, 1985). This is perhaps one of the most widely found differences among specific emotions. However, women also report mores sadness (Grossman and Wood, 1993; Allen and Haccoun, 1976), and more shame and guilt (Tangney, 1990).

While this is not an exhaustive review of the findings that document a gender difference with respect to emotional expressiveness and experience, it does demonstrate that in general, females are more emotional than males. However, this difference is not always found when other means of assessing emotions and emotional expressiveness are used. When a specific experience that elicits some emotion occurs, both men and women report equivalent levels of emotional experience. For instance, men actually report greater experience of some of the positive emotions when these are assessed by having participants keep a daily rating form. However, when these same emotions were recalled at a later date, this difference disappeared (Seidlitz and Diener, 1988).

Thus, there is a different pattern in the data on emotions, depending on how the self reports are acquired. When people are asked to give global assessments of their emotional experiences, as in the Affect Intensity Measure, there is a consistent gender difference, with women reporting more intense emotions and greater expression of emotions. In contrast, when the data are acquired by using a daily log or by assessing emotions immediately after an emotion-eliciting experience, this gender difference disappears.

There are at least four possible explanations for this basic difference in the data. First, women’s recall of emotions is represented in greater detail than men’s. This is what Seidlitz and Diener (1998) speculate may be the cause. Immediately after a situation, both genders accurately report their emotional experiences, but after a delay, females have a better representation of the experienced emotions in their memory.

A second and related explanation is that after an emotion-eliciting event, women may ruminate about the experience (Brody, 1999). Rumination involves the repeated re-living of an experience and related experiences. Rumination is found to occur more in women and is implicated in such disorders that disproportionately affect women like depression (Kuhl, 1981; Nolen-Hoeksema, 1990). It may be that just as women may feel more depressed after cognitively re-living negative experiences through rumination, they may have a cumulatively greater amount of emotion tied to a particular event after similar rumination.

Third, global assessments of emotion like the Affect Intensity Measure blur the distinction between the experience of emotions and the expression of emotions (Brody, 1999).

Fourth, global self reports or self reports of a past event may reflect gender stereotypes. Gender stereotypes may be the result of demand characteristics inherent in the questionnaires. In support of this possibility are results showing that children’s self reporting of emotions in response to a frightening movie were influenced by the children’s degree of social desirability. That is, among children who scored higher in social desirability, boys reported lower levels of fear. However, this difference was not found among children who scored low in social desirability (Eisenberg and Fabes, 1995). Also, among adults who endorsed gender stereotypes of emotions, more stereotypical levels of emotions were seen (Grossman and Wood, 1993). Specifically, among participants who endorsed gender stereotypes of greater anger among men, the women reported reduced anger and the men heightened anger. Similar results were found for other emotions.

Given that there are four plausible explanations for the fact that self report data generally find gender differences in emotionality but other measures do not, it may seem reasonable to conclude that the stereotypes of greater female emotionality are just stereotypes. However, this assessment does not take into account other measures of emotional experience or expression.

One such measure is to examine facial expression of emotions. When this is examined, women are more facially expressive and less able to inhibit facial expressions of emotions when asked to (Grossman and Wood, 1993).

One technique for studying facial expression of emotion is to use the slide viewing paradigm. In this paradigm, two sets of participants are used. One set serves as the sender of emotion while viewing an emotionally loaded or neutral slide. The other set of participants serves as the receiver of the emotion by observing the facial expressions of the sender. The sender in this type of study is unaware that his or her facial expressions are being monitored. In terms of the communication of specific emotions by the senders, females’ facial expressions communicated greater disgust, distress, fear, anger and surprise. Males’ facial expressions communicated greater embarrassment and guilt. Thus, on the majority of the emotions examined, the women were more expressive than the men (Wagner, Buck and Winterbotham, 1993).

In a different study, participants were told to attempt to either ingratiate themselves to another, to promote themselves to another or were not given any self presentation goal. It was expected that if instructed to attempt to ingratiate themselves to another person, people would minimize negative emotions in an effort to increase the likelihood that the person would "like them". It was also expected that if instructed to attempt to promote themselves to another person, people would display greater levels of negative emotion than in the other conditions. The results demonstrated that this pattern of results was true only for the male participants. Female participants were less likely to change their levels of negative and positive emotions according to their self-presentation goal (Levine and Feldman, 1997). Since men were more able to adjust their emotional display in accordance with their presentation goals, it may be that women’s emotions were too intense to alter. However, the authors point out that it may also be that women’s default mode may be to ingratiate themselves to others due to their greater emphasis on affiliative relationships compared to men. Although specific instructions were given to them regarding their self-presentation goals, they may have continued to attempt to ingratiate themselves to the target person.

Also, whether in posed or natural non-verbal expressions, women are more expressive than men for most emotions, with the exception of anger (Hall, 1984 in Brody, 1999). Women also use more emotion in their writing (Brody, Wise and Monuteaux, 1997), and in an observational study of the communication patterns of couples, wives disclosed more hostile emotions than husbands (Shimanoff, 1983). In support of the view that these differences in emotional expressiveness are indeed due to differences in emotional intensity, the results of electromyogram changes seen in response to the viewing of angry and happy faces also support the greater emotionality of women (Dimberg and Lunquist, 1990).

Anger in particular poses an interesting emotion for study. As described above, women produced greater facial expression of anger in response to a visual slide (Wagner, Buck and Winterbotham, 1993). When interviewed or observed in interactions, women express more anger than men (Dosser, Balswick and Halverson, 1983). In intimate relationships, it seems that women express more negative feelings that men (Kelley et al., 1978). However, men show more facial reactivity than women when viewing an angry facial expression (Dimberg and Lundquist, 1990). As described earlier, men and women do not differ in their physiological responses to anger-provoking situations, although the types of situations that made each gender angry differed somewhat (Frodi, 1976). Once again, there is no simple answer to the question of which sex experiences more anger. However, anger is one emotion that is more consistent with men’s gender roles and less consistent with women’s gender roles. Thus, any analysis of emotions based solely on gender role would find no support here since there is no pattern of greater expression of anger among men.

To further understand how men and women may differ in emotional reactivity, it is desirable to use a means of assessing this that will not be influenced by any demand characteristics. One approach is to use physiological measures of emotional reactivity or arousal. The following physiological measures will be described; acoustic startle responses to sudden tones, the inhibition of acoustic startle when preceded by a weaker stimulus (pre-pulse inhibition), and the brain wave activity that immediately follows the presentation of an unexpected stimulus (event-related potentials/ evoked potentials).

The simplest measure of emotional reactivity and arousal is to study the startle response. When in a quiet setting, a sudden loud burst of sound like the horn of a car can make a person jerk their head around, hunch their shoulders and direct their eyes to the direction of the sound. This general response can be considered a startle response. It is hypothesized to be an adaptive response to an unexpected, and therefore potentially dangerous stimulus. In the laboratory, this response can be observed by the attachment of electrodes to measure the contraction of the muscles of the eyes, the changes in skin conductance due to increased autonomic arousal and increased heart rate.

If these measures are sensitive to emotional arousal, they should detect differences between people experiencing an anxiety disorder and controls. Indeed, this is what is found. Both men and women suffering from post-traumatic stress disorder (PTSD) experience heightened autonomic reactivity, regardless of the source of the PTSD (Metzger et al., 1999). Furthermore, people with PTSD demonstrated decreased habituation to the startle stimulus. Normally, any stimulus that is repeatedly presented gradually loses its ability to induce a startle response. Essentially, we become accustomed to it and it loses its ability to startle us. This process appears to be attenuated in victims of PTSD, perhaps due to greater levels of nervous system arousal characteristic of the disorder. Heart rate measures also indicated that these individuals have increased reactivity to stimuli.

Another demonstration of the power of increased levels of arousal on startle came from studying children whose parents are diagnosed with anxiety disorders. Being the offspring of individuals with anxiety disorders places an adolescent at high risk of developing an anxiety disorder some time in life. Among this population, no current anxiety disorders had been detected. However, when presented with startle stimuli, they reacted with higher startle amplitudes (Grillon, Dierker and Merikangas, 1999). These two studies are described merely to introduce the reader to the research demonstrating that these techniques are sensitive to underlying levels of arousal and reactivity. As for gender differences in acoustic startle responses, some studies have noted a difference in overall levels of startle, with women showing larger startle responses than men (Casa, et al., 1998).

Also relevant to the study of gender differences in emotional reactivity are studies that have specifically compared the physiological responses of males and females to startle stimuli. One technique that has revealed a gender difference is pre-pulse inhibition. This refers to a procedure that results in inhibited startle to a pulse of noise. In this procedure, there are two types of presentations. A twenty millisecond burst of white noise at 80 dB is presented first. This pulse of sound is a relatively weak stimulus. It is almost immediately followed by a forty millisecond burst of 108 dB white noise. This latter stimulus is the startle stimulus that is measured. When reactions to the second, louder pulse of sound are examined, a pattern appears. The startle response to the loud pulse is significantly reduced on those trials when it was preceded by the weaker pulse. Thus, the weak pulse is said to inhibit the startle response to the louder pulse. Using this procedure, men have been found to be more inhibited by pre-pulse stimulation than women (Swerdlow et al., 1993; Swerdlow et al., 1995).

This suggests that males and females have somewhat different inhibitory mechanisms. Indeed, in another type of physiological measure, women were shown to have different responses which would be consistent with different inhibitory mechanisms between men and women. In the study of evoked responses to auditory stimuli, similar tones are repeatedly presented and then, interspersed with these repetitious tones will be a unique test tone. In one study where several recording sites across the skull were used and women and men were both studied, women had higher amplitude responses to the test tone, but not the original tone (Hetrick et al., 1996). Because of the pattern of responses, the authors concluded that this difference may reflect different types of inhibitory mechanisms acting on the neural systems underlying the evoked potentials, and not biological differences in the evoked responses to stimuli in general.

However, there are also reports demonstrating no difference in pre-pulse inhibition between men and women who formed the non-smoker control groups in one study designed to assess the effects of nicotine on pre-pulse inhibition (Casa et al., 1998). Thus, there is not unanimous consensus on the existence of the gender difference in pre-pulse inhibition.

However, in support of a role for gender in pre-pulse inhibitions, is the influence of menstrual cycles on these measures. Pre-pulse inhibition varies across women’s menstrual cycles. It is decreased during the luteal phase, especially during times of elevated of estrogen and progesterone (Swerdlow, Hartman and Auerbach, 1997). Thus, it may be relevant to control for menstrual cycle phase when comparing men and women.

In one of the few studies that have found gender differences in event-related potentials to auditory stimuli, both women and extroverts were found to have enhanced responses 300 ms following presentation of the stimuli (Cahill and Polich, 1992).

In summary, the literature available on gender differences in acoustic startle, pre-pulse inhibition and event-related potentials lacks a clear-cut pattern of consistent differences. However, where there are differences, it appears that females may have enhanced neural reactivity to stimuli and decreased inhibitory responses. This conclusion is consistent with the findings described earlier that suggest that women are more emotionally expressive than men, and at least with some measures, appear to be more emotionally reactive than men.

Finally, since there appear to be physiological differences in the neural responses of men and women to stimuli, it is of interest to speculate as to the function of these differential responses to stimuli and emotions. From an evolutionary standpoint, we may postulate that emotions have some current usefulness and that they have not been excluded from selective pressure (Oatley, 1993). Emotions are common in numerous species, and are thought to be critical for organisms to learn what actions lead to satisfying outcomes and what actions lead to unsatisfying outcomes. Thus, reinforcers and punishers acquire their power by eliciting emotional reactions in the individual. Even the negative emotion of anger can be viewed within this functionalist perspective. In one study of 139 families, 79% of the women reported that at least some good came out of arguments that lasted at least ten minutes with their spouses (Jenkins, Smith and Graham, 1989). In a different study, 62% of people who became angry and 79% of the targets of anger indicated that the anger had been beneficial to the relationship (Averill, 1982).

When we shift this question of the function of emotions to the topic of gender differences, we find that women’s roles and relationships benefit by a greater degree of emotionality. Women may have higher intimacy motivation, and so it may be beneficial to experience enhanced emotionality so as to better monitor intimate relationships. Indeed, when relationship differences are examined, it appears that women demonstrate greater vigilance over their relationships than men . As a result of this greater vigilance, women work to improve a relationship earlier than men, but will also give up on the relationship earlier than men who may get a later start on working on the relationship (Basow, 1992). Also, one may conjecture that since women are physically less able to defend themselves, they have a greater need for relationships in which to find a measure of personal safety (Brody, 1999). The underlying physiological differences reported between men and women may provide women the tools to better foster and maintain satisfactory relationships through greater emotionality.

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