Biological Constraints and the Pursuit of General Theories of Learning

Abstract

A constraint on a phenomenon is a limitation or boundary condition for its occurrence. Scientific investigations invariably lead to the identification of such boundary conditions. Studies of learning have documented numerous constraints, including, for example, the interval between conditioned and unconditioned stimuli (CS and US), the intensity and novelty of the CS and US, and the extent to which the unconditioned stimulus is surprising. Limitations on learning brought about by factors such as the CS–US interval and CS familiarity, for example, reliably occur in numerous situations in which classical conditioning is observed. The primary impetus for discussions about biological constraints on classical and instrumental conditioning was that certain learning phenomena were contrary to principles of learning widely held at the time, and being an exception t o the rule constituted a working definition of biological constraints.