Wednesday, March 02, 2005

The Limits of Introspection

In the talk I mentioned in my recent post, Sean Kelly discussed the ways one might account for the “constancies” in perception. This refers to the phenomenon whereby the color, size, and/or shape of an object is perceived to be the “same” from different perspectives (distance from object, angle, lighting), even as the details of the image presented to our retinas shift. An example used in the talk was a penny turned at an angle: while presenting an elliptical image, we still perceive it as round.

The key to the discussion was that to correctly characterize our perception in these cases one must distinguish between two modes of perceptual attitude which Kelly called the engaged and the detached. The engaged mode is our mode the majority of the time, when we are immersed in our activities. This mode, shaped by evolution and early development, is one where perceptions are guided (essentially automatically) in ways which serve our bodily goals (“motor-intentionality”). The detached mode describes the introspective investigation of our perceptions we undertake when we “step back” and reflect on a phenomenon.

The engaged mode is the one in which the “constancies” properly reside. In contrast, an account of perception which explicitly or implicitly makes use of the detached mode leads to misleading accounts of the phenomenon.

I’ve said in the past that investigations of consciousness which assume the primacy of what I’ve called the reflective or introspective mode of self-consciousness can be flawed. This introspective capability (which is of recent historical vintage and almost surely unique to humans) is part of our highest cognitive skill set, and yet, when applied to our own conscious experience, can obscure as well as illuminate the details of that experience.

This is discussed in detail in this SEP entry, “Phenomenological Approaches to Self-Consciousness”. The authors outline a distinction between reflective and pre-reflective self-consciousness with which I concur.

One place these limits come into play is in Benjamin Libet’s work on the temporal dimension of conscious experience. The experiment I’m thinking of is the one where subjects are asked to flick their wrists at a time of their choosing. Libet timed the wrist action and compared it to both a measured “readiness potential” detected in the motor cortex of the brain as well as the subjects’ own reports on when they experienced the desire to perform the action. Famously, the readiness potential preceded the reported time of experienced volition by an average of 0.5 seconds. Now, I think much of the commentary on this experiment suffered from a simplistic separation of the subjects’ internal states into the unconscious (the readiness potential) and the conscious (the report). By reporting on the experience, the subject had to bring the experience into reflective self-consciousness. This probably introduced a delay beyond what would be the case in the mode of pre-reflective self-consciousness (which couldn’t directly be measured in this setup). Nothing I’ve said means the experimental findings are not interesting and meaningful, but just that it may tell us more about the limits of the reflective mode of self-consciousness than it does about the divide between the conscious and the unconscious.

One final note I find interesting: the phenomenological account of self-consciousness in the SEP article I noted above dovetails nicely with the account described in this previous post, which was derived within the context of analytic philosophy.

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