Classical Conditioning

Abstract

Classical conditioning describes the learning process through which an innocuous stimulus (the to-be conditioned stimulus) acquires emotional valence by being paired with an unpleasant (aversive conditioning) or pleasant (appetitive conditioning) event, i.e., the unconditioned stimulus. In this chapter, classical conditioning is delineated as a fundamental mechanism for understanding pathological anxiety, fear, and trauma-related disorders as well as affective disorders and substance abuse. Developmental changes in fear learning will be outlined and how they may account for anxiety and trauma-related disorders in childhood. For example, the magnitude and speed of aversive conditioning increase from childhood to adolescence and adulthood, presumably mediated through changes in neural circuitries involving the amygdala and prefrontal brain areas. Importantly, traits, biological predispositions, and the impact of prior experiences are addressed, in that they make learning through classical conditioning highly flexible and interindividually variable. Moreover, the relative contribution of excitatory and inhibitory learning to exaggerated fear and anxiety is highlighted. Recent advances in our understanding that conditioning does not necessarily require direct experience, but can also occur by making use of imagery, will be summarized. Classical conditioning is not only crucial for understanding the development of psychopathology but has also been pivotal for the development of treatment interventions such as exposure therapy. Extinction learning and memory will be explained, and how the effectiveness of exposure therapy can be bolstered by taking into account what is known about extinction and its underlying mechanisms. Also, the boundaries between classical and operant conditioning are discussed and how a distinction can sometimes be difficult. Finally, an overview of interventions based on classical conditioning beyond exposure therapy is given, which highlights how powerful classical conditioning is in changing behavior, for example as demonstrated by its treatment benefits for various mental health problems during childhood and adolescence, including eating disorders, substance use disorders, nocturnal enuresis, and sleeping difficulties.