Broadly speaking, learning theorists concern themselves studying the mechanisms by which animals, including humans, acquire and utilize information about relationships between events. This endeavour includes the study of classical conditioning, instrumental conditioning, and the neural substrates that underlie these phenomena. The most enduring models that have emerged from this research argue that learning can be understood in terms of the formation of Pavlovian associations between events in the world (such as the sight of a dark alleyway and the witnessing of an assault) or instrumental associations between the agent's own actions and their consequences (such as choosing a restaurant and eating a delicious supper). Such associations are thought to provide the agent with the opportunity to anticipate the future and by dint of this knowledge behave adaptively on the basis of these predictions. However, the mechanisms of learning can sometimes go wrong, be undermined, or express themselves in an inappropriate manner, resulting in maladaptive behaviour. For example, individuals who are undergoing treatment for cancer will frequently experience unpleasant side effects of the cancer treatment (such as nausea and vomiting) that, with repeated treatment, may be elicited upon entering the clinic prior to the administration of the cytotoxic drugs themselves. To take another example, people who choose to inject themselves with heroin quickly report experiencing a rewarding sense of euphoria. However, long-term use of the drug can ultimately lead to chronic dysphoria. Both of these cases provide examples of a learning mechanism that enables the person to form associative connections between events (in one case the sight of a clinic and nausea, in the other injection of a drug and euphoria). Unfortunately, the consequences of this learning are far from desirable or adaptive and have signi®cant clinical implications. The goal of this book is to introduce the reader to a selection of clinical problems that are thought to be in¯uenced by the process of learning. In some cases it will be argued that the clinical problem itself is caused by a normally working learning mechanism (see, for example, the chapters by Symonds and Hall, and Field and Purkis). In other cases the clinical
the chapter by Moran and Rouse). In either case, the study of learning in both animals and people has provided us with an understanding of the conditions in which associative connections will, and will not, be formed between events. Armed with this knowledge, the clinician can apply the principles of learning theory to the clinical setting in order to either maximize the impact of a clinical intervention, or to better understand the conditions under which the clinical problem can emerge, and therefore prevent it.