Dissertation: Perceptual Context and the Nature of Neural Function

Localizing brain function is both a primary goal of neuroscience and a vexed theoretical issue. Virtually all positions in the long history of debates on localization have traded on a meta-theoretical assumption which I call "absolutism." Absolutism is the view that each functional part or area of the brain performs one univocal function, and does so regardless of the context in which it operates. Historically, those who think absolutist functions can be discovered have tended to support localization, those who disagree tend to deny it.

In my dissertation I undertook a sustained criticism of absolutism based on a detailed case study of visual area MT, traditionally construed as the "visual motion area." Despite being a hallmark success case for absolutist-style function ascription, the past 15 years of physiological research into MT have discovered that, far from responding solely to motion, it actually exhibits a diverse set of responses to different sorts of perceptual information, including depth and even color, in the right circumstances.

I argue that no version of an absolutist description of MT function is compatible with the current evidence. Instead, I articulate a "contextualist" view of functional localization, which posits that individual brain areas can be functionally distinguished based on their patterns of responses to perceptual and behavioral contexts. The contextualist view is an empirically adequate way of decomposing the brain, and I claim that it can meet the theoretical goals of functional localization.

In the course of the dissertation, I take up such issues as the nature of theories in systems neuroscience, the use of heuristics in biology, the role of computational neuroscience in functional decomposition, and the way in which theories generalize in complex-systems contexts. I am currently working on extending the insights of the contextualist view to such standard questions in philosophy of mind as the nature of representation and psychophysical reduction.