Take a peek into any chat room ... and you will find hundreds of individuals who personally know that Terri Schiavo is — despite voluminous testimony by her doctors and her guardians ad litem and the findings of multiple judges - capable of laughter and responsiveness and a full recovery. How do they know these things? The same way their elected representatives do: They watched a video clip.

I think I understand somewhat the parents' inabilty to let go of their daughter, and I can see how they could be fooled by what they see into honestly believing that she still has awareness and could, if only the right therapies were applied, recover. (I'm much less forgiving of their acceptance of right-wing funding.)

Just like our human capacity to see faces with only the smallest amount of information -- even where faces don't exist (as in grilled cheese sandwiches and on the surface of the moon) -- we are obviously predisposed to see intentional behavior wherever we can, even if it doesn't actually exist. It's easy to see why this would be, as the evolutionary advantages of understanding what other people (friends and enemies alike) are doing is apparent -- those who cannot "read" their competitors and adversaries correctly are likely to die and not procreate (and therefore do not pass on their genes), while those who correctly divine what others are going to do are more likely to survive. If that means that we occasionally see intentional behavior where it doesn't exist, as in those with severe brain dysfunction, that's a minor disadvantage compared to the benefits conferred.

(In his The Intentional Stance, philosopher Daniel Dennett points out that while the capacity for interpreting the intentions of others is probably largely innate -- and therefore evolutionarily determined -- the knowledge -- much of it presumably culture-specific -- needed to correctly "read" intentionality must come from experience and information imparted by others -- so, once again, we see a complex interaction between "nature" and "nurture.")

But while the parents' position is understandable and should provoke our sympathy (and empathy), people who jump to far-reaching conclusions about desperately important matters such as this based on 30 seconds or a minute or even 4 minutes of carefully selected videotape are inexcusable, no matter what their intuition tells them about the apparent intentionality of the behavior they see. Do they, and Senator Frist, for that matter, really think that their snap judgments are more valid than those of the doctors who have examined Schiavo, and the judges who have heard all the available evidence? If so, then either megalomania abounds in the land (which would certainly explain Frist), or else there are just too many people for whom ideology trumps rationality.

Update (3/24): This is from Martha Farah a neuroscientist and neuroethicist at the University of Pennsylvania:

Some observers of Terri Schiavo find her behavior indicative of conscious awareness and intentionality. One observer, writing on the website terrisfight.org wrote: “I was pleasantly surprised to observe Terri’s purposeful and varied behaviors... I never imagined Terri would be so active, curious, and purposeful. She watched people intently, obviously was attempting to communicate with each one in various ways and with various facial expressions and sounds.” For me, watching Terri Schiavo in the website videos, it was difficult not feel I was seeing a person interacting with others and aware of her surroundings.

However, clinical and experimental neuroscience have taught us some surprising things about the range of behaviors that can emerge from a decorticate brain. Such behaviors include orienting with eye and head movements toward sights and sounds, generating facial expressions, and producing nonverbal vocalizations that have meaning for us, if not the person producing them, such as cries and laughter. In light of this, we must interpret the behavior seen in the videos cautiously and with a measure of skepticism.

The most natural interpretation for the behaviors we see on the video is not the only interpretation. For example, when a dozing Terri is loudly ordered to “open your eyes!” and does so, does that mean she understood what was said? Or would she have done the same thing if roused with an equally loud order to “open your mouth!” or “stand on your head!”

Humans are hardwired to interpret the behavior of others in terms of mental states. In the psychology literature this tendency is part of a suite of abilities termed “Theory of Mind” (ToM) and in most situations we apply our ToM automatically, without weighing alternative reasons for the behavior. For a particularly striking demonstration of this fact about ourselves, consider the typical response to the robot Kismet. Kismet is part of a research effort at the MIT Artificial Intelligence Lab to design machines that interact socially with humans. Kismet has been programmed to gaze at humans who approach it, orient to salient objects moving within its field of view, pull back avoidantly if an object is thrust forward at it, and so on. People attribute all manner of cognitive and emotional states to this robot on the basis of a fairly small set of simple behaviors, and have been known to become quite attached to it. And this is a contraption made of metal and plastic, not a human being! My point is emphatically not to liken Terry Schiavo to Kismet, but rather to suggest a similarity in our reactions to the woman and the robot.