Much research on the brain and behavior depends on studies of rats and other lab animals. But animal behaviorist Joseph Garner at the University of California at Davis argues that animals housed in desolate cages often suffer brain dysfunction that renders them unfit as test subjects.
Garner noticed that parrots in small cages without toys or companions pace along their perches, bite the bars, walk in circles, and chew at the air. So he and his colleagues decided to administer a common psychological test, called the gambling task, to a group of nine captive-bred Amazon parrots. For one hour the birds were offered peanuts that drop at random into either of two food cups in their cages. The strategy that gains the most nuts is to peck at both cups with equal frequency, which is what healthy birds do. But eight of Garner's birds pecked persistently at one cup much more than the other. In humans, says Garner, that imbalanced response is consistent with dysfunction in the basal ganglia, the area of the brain that tells us what to do next.
Laboratory rats and mice housed in barren conditions also repeatedly bite the bars of their boxes; Garner's latest research, not yet published, suggests that these rodents also suffer from serious brain abnormalities. Still, new drugsincluding antidepressantsare routinely tested on them. "I don't think scientists should stop doing these tests," says Garner. "I think they should alter the environment to improve the quality of the model. Mice in enriched conditions are probably going to be much better models of normal human beings."