Pavlovian learning and conditioned reinforcement

Abstract

Conditioned reinforcers are widely used in applied behavior analysis. Basic research evidence reveals that Pavlovian learning plays an important role in the acquisition and efficacy of new conditioned-reinforcer functions. Thus, a better understanding of Pavlovian principles holds the promise of improving the efficacy of conditioned reinforcement in applied research and practice. This paper surveys how (and if) Pavlovian principles are presented in behavior-analytic textbooks; imprecisions and knowledge gaps within contemporary Pavlovian empirical findings are highlighted. Thereafter, six practical principles of Pavlovian conditioning are presented along with empirical support and knowledge gaps that should be filled by applied and translational behavior-analytic researchers. Innovative applications of these principles are outlined for research in language acquisition, token reinforcement, and self-control.

Keywords: Pavlovian conditioning; conditioned reinforcement; impulsivity; language acquisition; praise; token economy.

FIGURE 1

Presentations of neutral and unconditioned stimuli in Pavlovian conditioning procedures. Four ways in which the neutral stimulus (NS) and unconditioned stimulus (US) might be presented in time in these procedures.

FIGURE 2

Three Pavlovian conditioning procedures. Panels A and B illustrate the two durations in the C/T ratio. C is the “cycle time” or the average interval separating successive unconditioned stimulus (US) events; T is the interval from conditioned stimulus (CS) onset to US delivery. By dividing C by T, we obtain a C/T ratio value (the quotient). In Panel C, the CS→US temporal contiguity is the same as in Panel A but the average inter-US interval (C) is shorter. Hence, Principle 3 holds that Panel A is the more effective procedure because of its longer duration of C.

FIGURE 3

Pavlovian overshadowing procedures. The top panel shows the training phase for the Pavlovian group—a neutral stimulus (NS1) is presented 10 s before the unconditioned stimulus (US), and US events happen, on average, every 130 s. For the overshadowing group, everything is the same except a second, highly salient neutral stimulus (NS2) is presented simultaneously with NS1. In the test phase, NS1 is presented alone to evaluate if it will evoke a conditioned response.

FIGURE 4

Pavlovian blocking procedures involving a neutral stimulus (NS), conditioned stimulus (CS) and unconditioned stimulus (US). In Phase 1, the NS→US sequence at C/T = 10 establishes the CS function (C refers to the inter-US interval and T to the CS→US interval). In Phase 2, procedures are unchanged with the exception that an NS is presented simultaneously with the functional CS. In the test phase, the NS is presented alone to evaluate if it will evoke a conditioned response.

FIGURE 5

Pavlovian acquisition data. Panel A: Number of Pavlovian training trials needed before mice met an acquisition criterion (i.e., the CS alone reliably evoked the conditioned response) plotted as a function of the number of NS→US trials completed per session (Gallistel & Papachristos, 2020). Panel B: Conditioned response rate in a rat autoshaping experiment (Papini & Dudley, 1993). In rats completing one trial per session, the NS evoked conditioned responding at above baseline levels by the 4^th trial block. For rats in the 20-trials per session group, the NS was not yet evoking conditioned responding after 40 training trials. Panel C: Sessions to acquisition across groups that acquired the CS function.