Vive la Différence

Psychoanalysis has long been interested in the differences between men and women—the mental differences—and has been a major participant in the dialogue and controversy that have surrounded this subject from before Freud until the current president of Harvard. Freud's most well-known formulation was clear—the essential psychological differences between the sexes could be traced to their reactions to the discovery of genital differences. Anatomy was destiny—the anatomy of the genitalia and the psychological responses to it. Men and women had the same brains, but different developmental experiences.

One modification of this model added a social or relational theme, a theme that became widespread in psychoanalytic thinking. The critical experiences that differentiated boys from girls were not only their own psychological responses to the discovery of their genitalia, but also, and more important, their parents' response. Mothers and fathers behave differently with sons and daughters, and the response to those differences led to gender differences in psychology, differences that were not closely tied to mating behavior.

A second modification came from biologic research. Sex hormones were found to affect the hypothalamus and thereby organize divergent reproductive behavior. This provided a biologic basis for gender specific behavior in mating.

Now new research has added yet another perspective. The brains of men and women are different; these differences are present from birth. They involve areas of the brain that are not associated with reproductive behavior and they seem to be associated with behavioral differences that have little to do with mating. In this model anatomy may still be destiny, but it is neuroanatomy rather than genital anatomy and it affects non-conflictual capacities as well as mating behavior and associated fantasies.

Psychoanalysis has long been interested in the differences between men and women—the mental differences—and has been a major participant in the dialogue and controversy that have surrounded this subject from before Freud until the current president of Harvard.

The new findings are largely based on new methods of studying brains, positron-emission tomography (PET) and functional magnetic resonance imaging (fMRI) as well as more traditional neuroscientific and psychologic tools. They have demonstrated differences between men and women in both gross and microscopic brain anatomy, differences that correlate with areas of the brain that contain the highest concentration of sex hormone receptors during development.

There are also studies of behavioral differences that seem to point to constitutional rather than acquired differences that are linked to gender. For example, baby monkeys mimic humans in their preference for “gender appropriate” toys, and in monkeys it seems unlikely that what is gender appropriate has been learned from social attitudes. Further, human infants show gender-linked preferences in the direction of attention (human faces vs. mechanical toys) when they are only one day old!

There are more complex gender differences in responses to separation, responses to stress, and in the impact of drugs on memory. At this point, the data do not lead to a new comprehensive formulation so much as shake the old one.

One example of these differences: The memory of emotionally distressing stimuli correlates with activation of the amygdala. However, in men it is the right amygdala; in women the left amygdala. Furthermore, if this activation is dampened by drugs, memory is affected. However, the effect is different in men and women; in men the central theme of the memory is impaired (right brain), in women the memory of the peripheral details (left brain). This has implications for the response to trauma, the nature of traumatic memories, and the way in which one might approach their treatment.

Males and females are different, and that includes psychological differences. These differences may stem from early developmental experiences with their bodies, from social learning in response to their parents, from the effects of hormones on gender specific behavior, and now we can add from differences in their brains and behavioral repertoires that antedate all of these others. The implications of these findings for developmental psychology psychopathologythe process of psychoanalysis, and the limits of psychoanalysis are yet to be explored.

The new neurobiologic findings are reviewed by Larry Cahill of the Department of Neurobiology and Behavior and the Center for Neurobiology of Learning and Memory of the University of California, Irvine, in the Scientific American, May 2005.