The animal-human analogy

Several days ago, I commented on an article by Price in which information about mouse behavior was
[over]generalized to suggest that human beings showed similar factors at work in maternal behavior. This tendency to equate behaviors of different species has become quite common, especially in textbooks for undergraduate courses, where authors hesitate to acknowledge that they are using animal studies. (This hesitation is not just because of the problems human-animal analogies create, but because of the strength of organizations like PETA that object to experimental work with animal subjects.)

The issue of human-animal comparisons is one we should think about in this Darwin anniversary year. My concern is not about rejecting all such comparisons. Some do reject the analogy on the grounds that humans are special, made in God's image, have souls, etc., and thus are not comparable to non-humans. I accept the comparison and think it can be valuable-- but only when it is used with caution.

The human-animal analogy is easily "abused" by people who consider that what is known about one must provide reliable information about the other. In fact, such reasoning only works when careful comparisons have been made of the characteristics the two groups have in common AND that are relevant to the question at hand. Mice have fur, humans have hair; this commonality is relevant to skin functions, but probably not to the study of maternal behavior. Humans mourn over dead babies; mice eat them-- does this difference mean they have nothing relevant in common? Only attention to detail can tell us where we are in any comparison of one species to another.

As J.P. Scott showed many years ago, not only species but strain differences shape social behavior in dogs. Comparing one strain of one species to members of another species may give quite different results than if another strain were used in the comparison.

Studies of animal behavior are fascinating and valuable in themselves. Sometimes it may be possible to use their data to explain human characteristics-- but sometimes, and more often, not. To find out about a species, it's best to study that species.