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WCMA Blog

How“Male” and “Female” Brains Might Lead to “Male” and “Female” Art

Katy Schimert’s floor piece, A Woman’s Brain, was inspired by an interest in the differences between the male and female brain. Given the well-documented existence of sex differences in a variety of behavioral domains (e.g., mental rotation ability, verbal fluency, willingness to ask for directions when lost), it would be naïve to think that male and female brain are identical. Only relatively recently, though, have sex differences in neuroanatomy been identified. Geoffrey Raisman and Pauline Field (1973) were the first to document a sexual dimorphism. These researchers focused their attention on a small region in the rat brain known as the medial preoptic area (MPOA). Raisman and Field carefully counted and categorized the sites of communication between neurons within the MPOA. Their fundamental finding was that these synapses were distributed differently along the neurons in male brains compared to female brains.

Several years later, Roger Gorski and his colleagues (1978) discovered a much more obvious difference in what became known as the sexually dimorphic nucleus of the preoptic area (SDN-POA). Gorski reported that this group of neurons is much larger in male brains than female brains. In fact, if brains are thinly sliced and the resulting sections are mounted onto slides and stained, you can see the much larger SDN-POA of male brains when they are lined up alongside female brains. It’s a huge difference – no microscope is required!!!

What causes these differences? One important factor in the differentiation of male and female brains is the hormone testosterone. Early in development, the testes of males secrete brief surges in testosterone. This hormone travels through the bloodstream to the developing brain. Within the neurons of the brain, testosterone and its metabolites bind to specific receptors and can ultimately affect the survival of the cell. In this way, early exposure to androgens can masculinize brain structures like the SDN-POA while the absence of androgens results in a female-like brain organization. Interestingly, administering exogenous testosterone to females during this critical period of differentiation results in an increase in the size of the SDN-POA; likewise, preventing the action of these hormones in males causes a decrease in the size of the SDN-POA.

Clearly male and female brains differ, but do these differences – many of which result from hormonal events very early in development – affect the ways that males and females view or create art? Recent studies have confirmed what might be obvious to the casual observer spending an afternoon in an elementary school art room. Girls tend to draw with warmer colors (e.g., reds, pinks) while boys draw with cold colors (e.g., blues, grays); girls draw more humans and nature motifs (e.g., flowers, butterflies) while boys draw mobile and mechanical objects (e.g., trucks, planes); girls depict objects in a row from a ground perspective while boys more frequently use a bird’s-eye perspective (Iijima et al., 2001).

Surely many factors contribute to the a child’s decisions about what objects to draw, what colors to use, and what perspective to take. But according to data collected by Megumi Iijima and her colleagues (2001), hormonal events during early development may play a particularly significant role. These researchers analyzed the drawings of 124 boys and 128 girls from six kindergartens and noted the significant differences in color use, motifs, and perspectives. The drawings of eight 5-yr-old girls with congenital adrenal hyperplasia (CAH) were also examined. CAH is a condition characterized by the lack of an enzyme involved in the synthesis of cortisol, a hormone produced by the adrenal glands. Without this enzyme, the precursors to cortisol cannot be converted into cortisol and are, instead, converted into androgens. As a result, females with CAH are often exposed to exceptionally high levels of androgens during the periods of development that are critical for sexual differentiation of the brain. Interestingly, the artwork created by the girls with CAH exhibited characteristics that are more typical of the drawings of boys than those of unaffected girls. Thus, early androgen exposure may lead to a more masculinized brain and, perhaps, more male-typical decisions when creating art.

Hormone exposure during early development has been shown to influence the development of visual pathways in primates (Bauer et al., 1986; Held et al., 1988) and rodents (Salyer et al., 2001). The early endocrine environment also influences later play behavior, toy preferences, and other sexually dimorphic behaviors. We now have evidence that the early endocrine environment may also influences the artistic tendencies of children. Katy Schiemert’s art is based on the idea that male and female brains are different. These differences, derived in part from endocrine events very early in development, may contribute to sex differences in the creation, perception, and appreciation of art.

References

Bauer, J.A., Shimojo, S., Gwizada, J., & Held, R. (1986). Sex differences in the development of human infants. Investigative Ophthalmology and Visual Sciences, 27, 265-273.

Gorski, R.A., Gordon, J.H., Shryne, J.E., & Southam, A.M. (1978). Evidence for a morphological sex difference within the medial preoptic area of the rat. Brain Research, 148, 333-346.

Held, R., Bauer, J., & Gwiazda, J. (1988). Age of onset of binocularity correlates with level of plasma testosterone in male infants. Investigative Ophthalmology and Visual Scineces, 29, 60.

Iijima, M., Arisaka, O., Minamoto, F., & Arai, Y. (2001). Sex differences in children’s free drawings: a study on girls with congenital adrenal hyperplasia. Hormones & Behavior, 40, 99-104.

Raisman, G. & Field, P.M. (1973). Sexual dimorphism in the neuropil of the preoptic area of the rat and its dependence on neonatal androgen. Brain Research, 54, 1-29.

Salyer, D.L., Lund, t.D., Fleming, D.E., Lephart, E.D., & Horvath, T.L. (2001). Sexual dimorphism and aromatase in the rat retina. Developmental Brain Research, 126, 131-136.

- Noah Sandstrom, Associate Professor of Psychology, Williams College

Above images: Noah Sandstrom’s ‘Brainy Talk’ at WCMA’s Family Day where children of all ages actually got to touch brains!

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