Does Variability Training Facilitate Learning in Two Genetically Divergent Mouse Strains?

Abstract

Variability is an operant dimension of behavior so the degree of variability observed depends upon the reinforcement contingency. One approach to reinforcing variations is the threshold procedure, in which a particular response or response pattern, out of several possible ones, produces reinforcement if it occurs infrequently relative to other responses. Behavioral variability is also associated with clinically relevant populations. Individuals with Autism Spectrum Disorders (ASD) tend to behave in a highly repetitive manner compared to controls, whereas individuals with Attention Deficit Hyperactivity Disorder (ADHD) tend to behave in a highly variable manner. The purpose of the first experiment was to assess whether the BALB/c mouse strain, a proposed murine model of behavioral deficits associated with ASD, also models invariant responding characteristic of ASD compared to control, C57Bl/6 mice. Behavioral variability is imperative to the acquisition of novel responses, i.e., learning. Concurrent reinforcement of operant variations facilitates the acquisition of a difficult response. The purpose of the second experiment was to determine whether a history of variable responding during a critical period of development, adolescence, affects learning in adulthood using an Incremental Repeated Acquisition (IRA) task with a Performance and Learning condition. On the IRA task, performance sessions approximate behavioral repetitions because the target response does not change from session to session whereas learning sessions require organisms to acquire a new target response each session.