Peter Marler University of California, Davis
I sense from the classical debate between Piaget and Chomsky ( Piattelli- Palmarini , 1980) that at least some of us are all too prone to think of learning and instinct as being virtually antithetical. According to this common view, behavior is one or the other, but it is rarely, if ever, both. Lower animals display instincts, but our own species, apart from a few very basic drives, displays instincts rarely. Instead, we are supposed to be the manifestation of what can be achieved by the emancipation from instinctive control ( Gould & Marler, 1987).
It is self-evident that this antithesis is false. Just as instincts are products of interactions between genome and environment, even the most extreme case of purely arbitrary, culturally transmitted behavior must, in some sense, be the result of an instinct at work. Functions of instincts may be generalized or highly specialized, but without them learning could not occur. Thus, the question I pose is not "Do instincts to learn exist?" but rather "What is their nature, and by what behavioral and physiological mechanism do they operate?" How do they impinge on the pervasive plasticity that behavior displays at so many points in the course of its development? I suggest that concepts from the classical ethology of Konrad Lorenz ( 1950) and Niko Tinbergen ( 1951) are instructive in a search for answers to these questions.
Of the several concepts with which Lorenz and Tinbergen sought to capture the essence of instinctive behavior in animals (listed in Table 2.1), I concentrate especially on three. First is the notion of sensitive periods as phases of development with unusual potential for lability. Second and third are the complementary ideas of releasers (or sign stimuli) and innate release mechanisms, invoked by ethologists to explain the remarkable fact that many