Sign Stimuli and Human Taxonomies

• Welcome to the BOL Forum on Evolutionary Psychology by John Grohol, 3/19/97
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    • Species Categories and Psychophysics by James Brody, 5/17/98
      
      

There are two critical questions here: 1) How do we (humans) categorize things/events? 2) What similarities in categorization do we share with other creatures?

Jim's survey suggests valuable future studies.

One I have recently become interested in is how we categorize behavior. Here we have a flow of events that we somehow break into categories (sort of a verb to noun transition). We then put meaning on those categories, such as "this is aggression" and "that is play". We go way beyond the observables in many such inferences. It is useful to ask how and why.

Some would say that our categories are indeed an imposition of discontinuities upon a nature that is basically continuous. Others say the world has natural break points. It has proven difficult to get firm evidence.

The early ethological studies of animal responses to "sign stimuli" are informative. Sticklebacks do not need what to humans is a good model of other sticklebacks to respond. A stick with a "red belly" will do just fine to elicit territorial aggression, for example. People may well have their own (poorly understood) triggers that lead us to say a "this is a this" and "that is a that". Most likely, we - as the stickleback - extrapolate from partial glimpses of the world. The fact that we may agree, thus be "objective", is in itself not more reassuring than that male sticklebacks can agree on what images to attack.

So we have a problem. We seek agreement, objectivity, to find out the way the world "really is", and may end up checking ourselves through shared biases. Some of these biases almost certainly have strong biological origins; others are clearly dictated in large part by tradition. Its hard to extracate oneself from either.

Thus, as I think Jim suggests, comparing our categories with one another and with those suggested by other species can be a way toward more full evaluation. Not easy. A supplementary approach which I like is to intentionally take on a different stance - what would happen if I assume this rather than that...now what do I see. This can be done.

So, is light a wave or a particle? Some say the whole question is one without answer. One measure says wave; another measure says particle. Our logic says light cannot be both. Stuck.

Our concepts do get us stuck. Even our logic can get us stuck. These and related facts may be where the real action is. Can we understand better what it is that gets us stuck? We are often so busy trying to find out how the world really is organized that we forget to look at where we are stuck. Maybe we need a science of "stuckiness"!

Are species a "natural category"? Are they "discrete"? There are so many avenues into such taxonomic questions that a single answer may long be elusive. Sure is fun to ask, however!

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