Tuesday, March 15, 2005

i see what you mean

Cognitive Daily looks at the neural basis for perception of biological motion. Shown images that consist of a black background with a single white dot placed at each major joint of the human body (a 'point-light display'), people have no problem identifying the image as a person and are even able to make some assumptions about the gender and mood of the person in the image. Birds and cats are able to do this as well, suggesting that the ability to identify biological motion might be hard-wired. In evolutionary terms it is useful to know at a glance whether or not the person approaching you is a threat - if your fight-or-flight circuitry kicks in, it's best to have messages dispatched to the muscles well in advance of conscious evaluation.

"So what are you saying? That I can dodge bullets?"
"No... what I am trying to tell you is that when you're ready, you won't have to."

It is interesting that when animals do something like this, we call it 'instinct', but when humans do the exact same thing we pull out the thesaurus to find a more complicated label... because we're *special*.

The BioMotionLab (Shockwave flash) app lets you explore your own perception of biological movement - there is a walking human point-light display with slider-bar adjustments for gender, weight, nervousness, and happiness. I wish there were other adjustments for culture and physical workload - the former because the app's interpretation of types of movement seems rather Euro/US-centric, the latter because people who work in the fields their whole lives are going to move differently from cubicle-dwellers.

How much of our perception is instinct, and how much is enculturation? I've been places where big arm movements are considered crass, where you need to make sure you aren't pointing your feet at anyone, where touching someone's head is A Bad Thing. Do people from those cultures interpret the bounce in someone's step the same way I do? What sort of assumptions do they make about people glimpsed in the periphery of their vision, what sort of information is gleaned from a glance? I doubt that the differences in perception can be summed up with a little slider bar.