Grabov Rat : weekly : images and thoughts

The parrots of Brisbane. For the past few weeks, many Brisbane residents saw them or at least heard the resounding cries of these cherry-headed conures made famous by the Mark Bittner's book The Wild Parrots of Telegraph Hill. They’ve never ventured out of San Francisco until this year; Bittner estimated that there are now 200 parrots in the flock. The cherry-headed conures are originally from Ecuador and Peru. Before 1993, people were able to import them legally into the United States; they sold for less than $100 each. The Telegraph Hill colony in San Francisco began with birds that escaped or were released. I understand their move to Brisbane quite well: coming to Bay Area I've moved to Brisbane directly, I even didn't try to live in San Francisco.

The central idea of the philosophy of behaviorism, that behavior and the mind have an entirely materialist basis subject to experimental analysis, is fundamentally sound. Nevertheless, the underlying assumptions of simplicity and equipotentiality in learning have crumbled. In their place has emerged a picture of the existence of many peculiar types of learning that conform to no general law except, perhaps, evolution by natural selection. The learning potential of each species appears to be fully programmed by the structure of its brain, the sequence of release of its hormones, and ultimately, its genes. Each animal species is "prepared’ to learn certain stimuli, barred from learning others, and neutral with respect to still others. For example, adult herring gulls quickly learn to distinguish their newly hatched chicks but never their own eggs, which are nevertheless just as visually distinct.

Even more impressive examples have been discovered. Each year indigo buntings migrate between their breeding grounds in eastern North America and their wintering grounds in South America. Like many of our other native birds they travel at night. After leaving the nest, young buntings are prepared to learn the north star and circum-polar constellations, which they proceed to do quickly and automatically. They are inhibited from learning the other constellations.

So some of the more rigid forms of animal instinct can be based on idiosyncratic forms of prepared learning. But is human learning prepared? We like to think that given enough time and will power we can learn anything. Yet constrains exist.

Edward O. Wilson: On human nature, Harvard University Press, Cambridge, MA, 1978.