Can we ever know whether there is a gender difference in the corpus callo – sum?107 Well, it depends a bit on what we mean by knowing. The corpus callo-

Talking Heads: Do Facts Speakfor Themselves?

Talking Heads: Do Facts Speakfor Themselves?

figure p. 7A (top): The ‘‘science half’’ of the woven knowledge connections; p. 7B (bottom): The ‘‘culture half’’ of the woven knowledge connections.

(Source: Alyce Santoro, for the author)

sum is a highly variable bit of anatomy. Scientists go to great lengths to fix it in place for laboratory observation, but despite their efforts it won’t hold still. It may or may not change, depending on the experience, handedness, health, age, and sex of the body it inhabits. Knowing, then, means finding a way to approach the CC so that it says the same thing to a wide array of investigators. I think the likelihood of this happening is small. Ultimately, the questions researchers take into their studies, the methodologies they employ, and their decisions about which additional persuasive communities to link their work to, all reflect cultural assumptions about the meanings of the subject under study—in this case, the meanings of masculinity and femininity.

A belief in biologically based difference is often linked to conservative so­cial policy, although the association between political conservatism and bio­logical determinism is by no means absolute.108 I cannot predict on a priori grounds whether or not in the future we will come to believe in gender differences in the CC, or whether we will simply let the matter fall, unre-

solved, by the wayside. If we were to reach social agreement on the politics of gender in education, however, what we believe about CC structure wouldn’t matter. We know now, for example that ‘‘training with spatial tasks will lead to improved achievement on spatial tests.’’109 Let’s further suppose that we could agree that schools ‘‘should provide training in spatial ability in order to equalize educational opportunities for boys and girls.’’110

If we were culturally unified around such a meaning of equal opportunity, the CC dispute might follow one of several possible paths. Scientists might decide that, given how little we still know about how the CC works, the question is premature and should be set aside until our approaches to tracing nervous function in the CC improve. Or they might decide that the difference does exist, but is not forever fixed at birth. Their research program might focus on which experiences influence such changes, and the information gained might be of use to educators devising training programs for spatial ability. Feminists would not object to such studies because the idea of inferior­ity and immutability would have been severed from the assertion of difference, and they could rest secure in our culture’s commitment to a particular form of equal educational opportunity. Or we might decide that the data, after all, do not support a consistent anatomical group difference in the CC at any point in the life cycle. We might, instead, ask research questions about the sources of individual variability in CC anatomy. How might genetic variability interact with environmental stimulus to produce anatomical difference? Which stim­uli are important for which genotypes? In other words, we might use develop­mental systems theory to frame our investigations of the corpus callosum. Choosing a scientific path acceptable to most, and littering that path with agreed-upon facts, is only possible once we have achieved social and cultural peace about gender equity. Such a view of fact formation does not deny the existence of a material, verifiable nature; nor does it hold that the material— in this case the brain and its CC—has no say in the matter.111

The CC is not voiceless. Scientists, for example, cannot arbitrarily decide that the structure is round rather than oblong. With regard to gender differ­ences, however, let’s just say that it mumbles. Scientists have employed their immense talents to try to get rid of background noise, to see if they can more clearly tune in the CC. But the corpus callosum is a pretty uncooperative medium for locating differences. That researchers continue to probe the cor­pus callosum in search of a definitive gender difference speaks to how en­trenched their expectations about biological differences remain. As with in­tersexuality, however, I would argue that the real excitement of studies on the corpus callosum lies in what we can learn about the vastness of human varia­tion and the ways in which the brain develops as part of a social system.