Operant conditioning of infant monkeys (Macaca fascicularis) for toxicity testing.

A technique has been developed that allows infant monkeys to perform on an operant schedule as soon as they are able to self-feed. Behavior is shaped in small increments through a series of operants; sensory and motor systems as well as performance on schedules using intermittent reinforcement may be tested as early as 3-4 weeks of age. This is accomplished by exposing the infant to the operant situation almost continuously, and allowing the infant to feed only by operantly responding. Infants exposed to lead post-natally differed from controls in pattern of fixed ratio responding, "activity" as measured by pattern of responding over the course of the session, and on a two-choice form discrimination reversal learning set paradigm. This technique allows rapid accumulation of large amounts of data without experimenter intervention.