Appetitive Pavlovian-instrumental Transfer: A review

- We present a systematic review of appetitive Pavlovian Instrumental Transfer.
- We review and discuss all major experiments and interpretations.
- We discuss the interactions between transfer and drugs of abuse.
- We examine the recent applications of transfer to human participants.
- We highlight open problems, such as inhibition and the function of transfer.

Reward-related cues are an important part of our daily life as they often influence and guide our actions. This paper reviews one of the experimental paradigms used to study the effects of cues, the Pavlovian to Instrumental Transfer paradigm. In this paradigm, cues associated with rewards through Pavlovian conditioning alter motivation and choice of instrumental actions. The first transfer experiments date back to the 1940s, but only in the last decade has it been fully recognised that there are two types of transfer, specific and general. This paper presents a systematic review of both the neural substrates and the behavioral factors affecting both types of transfer. It also examines the recent application of the paradigm to study the effect of cues on human participants, both in normal and pathological conditions, and the interactions of transfer with drugs of abuse. Finally, the paper analyses the theoretical aspects of transfer to build an overall picture of the phenomenon, from early theories to recent hierarchical accounts.