Advancing and Integrating the Cusp Concept to Understand Behavioral Repertoire Dynamics.

The behavioral repertoire grows and develops through a lifetime in a manner intricately dependent on bidirectional connections between its current form and the shaping environment. Behavior analysis has discovered many of the key relationships that occur between repertoire elements that govern this constant metamorphosis, including the behavioral cusp: an event that triggers contact with new behavioral contingencies. The current literature already suggests possible integration of the behavioral cusp and related concepts into a wider understanding of behavioural development and cumulative learning. Here we share an attempted step in that progression: an approach to an in-depth characterization of the features and connections underlying cusp variety. We sketch this approach on the basis of differential involvement of contingency terms; the relevance to the cusp of environmental context, accompanying repertoire, or response properties; the connections of particular cusps to other behavioral principles, processes, or concepts; the involvement of co-evolving social repertoires undergoing mutual influence; and the ability of cusps to direct the repertoire either toward desired contingencies or away from a growth-stifling repertoire. We discuss the implications of the schema for expanded applied considerations, the programming of unique cusps, and the need for incorporating cultural context into the cusp. We hope that this schema could be a starting point, subject to empirical refinement, leading to an expanded understanding of repertoire interconnectivity and ontogenetic evolution.

A within-subject between-apparatus comparison of impulsive choice: T-maze and two-lever chamber.

Whereas intertemporal choice procedures are a common method for examining impulsive choice in nonhuman subjects, the apparatus used to implement this procedure varies across studies. The purpose of the present study was to compare impulsive choice between a two-lever chamber and a T-maze. In Experiment 1, rats chose between a smaller, immediate reinforcer and a larger, delayed reinforcer, first in a two-lever chamber and then in a T-maze. Delay to the larger reinforcer changed in an ascending and descending order (0-32 s) across sessions. Experiment 2 examined the same between-apparatus comparison but under steady-state conditions with the delay fixed at 32 s. In Experiment 1, choice for the larger, delayed reinforcer was generally higher in the T-maze than in the two-lever chamber. Similarly in Experiment 2, steady-state choice for the larger, delayed reinforcer was higher in the T-maze. Choice for the 32-s delayed reinforcer was also greater in Experiment 2 than in Experiment 1, suggesting that extended exposure to the delay is required for the T-maze to yield reliable impulsive choice data. While the reasons for the between-apparatus discrepancies are at present unknown, results from both experiments clearly demonstrate that the apparatus matters when assessing overall level and reliability of impulsive choice data.