Human emotions play an important role in individual and group behaviors, influencing both prosocial and antisocial exchanges.  Complex and personal, emotions are difficult to study.  Although physiological indicators of emotion, such as pulse or skin conductance, are easy to measure, the subjective experience of emotion is much harder to assess.Further complicating the issue, there is no universally accepted theory regarding the role of physiological processes in the experience of emotion.  Common sense would suggest that emotion is experienced first, followed by physiological and behavioral events: we feel scared and then break into a cold sweat.  However, one of the earliest modern theories of emotion proposed just the opposite—emotion occurs after a physiological response, not before: we break into a cold sweat and then feel scared.Males and females also appear to experience emotion differently; however, it is unclear whether this is the result of nature or nurture.  Studies using functional magnetic resonance imaging (fMRI) suggest a biological difference.  Data suggest that compared to females, males demonstrated greater activation of the amygdala while viewing images meant to induce fear, anger, or sexual arousal, but when asked to suppress negative emotions, females demonstrated greater activation of the prefrontal cortex than males.  Research also suggests that females may demonstrate more empathy; when watching another person experience an emotion (eg, pain), females show more neural activation of the same areas that are active during the personal experience of that emotion.Social factors also appear to play an important role in gender differences.  One study, which assessed how boys and girls express emotion from infancy to adolescence, concluded that gender differences appear to emerge around age 2–4 and become more pronounced with age.  The researchers hypothesized that children learn gendered behavior regarding emotion through social learning.  Cultural differences in the expression of emotion lend support to this argument: several studies suggest that, in general, men are expected to express less emotion than women, with the exception of anger.T. Singer and C. Lamm ©2009 by New York Academy of Sciences, and T. M. Chaplin and A. Aldao ©2012 by American Psychological Association, and S. R. Wester, D. L. Vogel, P. K. Pressly, and M. Heesacker ©2002 by American Psychological Association Question 22This passage considers how gender differences in emotion may result from all of the following, EXCEPT:A.social learning overriding genetic predisposition starting around age 2–4.B.socialization across an individual's lifespan.C.social and cultural norms that differ for men and women.D.physiological differences between the brains of males and females.