Controlled and automatic processes in Pavlovian-instrumental transfer

Abstract

The current research aimed to further current knowledge on the psychological processes that underpin human outcome-selective Pavlovian-instrumental transfer (PIT) effects. PIT reflects the capacity of a Pavlovian stimulus to selectively potentiate an instrumental response that predicts a common rewarding outcome. PIT effects are often suggested to reflect a relatively automatic S-O-R mechanism, where the stimulus activates the sensory properties of the outcome, which then automatically triggers associated instrumental responses. The current research tested this S-O-R account of PIT against a propositional expected utility theory, which suggests that PIT effects reflect verbalizable inferences about the probability and value of each outcome. Chapter 1 reviews the relevant literature. Chapters 2-4 then report 11 experiments that aimed to set the S-O-R and propositional theories against one another. In Chapter 2, two experiments demonstrated that PIT is sensitive to a reversal instruction (Experiment 2), but is robust against a time pressure (Experiment 1) and concurrent load (Experiment 2) manipulation. Chapter 3 details the development of a novel outcome devaluation procedure, and reports four experiments that examined the effect of both outcome devaluation and verbal instructions on PIT. These experiments demonstrated that a typical PIT procedure produces PIT effects that are insensitive to a very strong devaluation manipulation. Furthermore, PIT effects were observed for a devalued outcome even when an S-O-R mechanism was unlikely to control behaviour. Chapter 4 reports five experiments that show that PIT is highly sensitive to outcome devaluation when multiple outcomes and responses are cued on every transfer test trial. Chapter 5 therefore concludes that, on balance, the results provide converging support for the propositional expected utility theory of PIT.