Unraveling the Building Blocks of Classical Conditioning

Chapter 8 examines the many variables that affect the effectivity of a conditioned stimulus (CS) and unconditioned stimulus (US) in eliciting a conditioned response (CR). The chapter describes experiments showing that preexposure trials to the CS or US can retard the acquisition of a subsequent CS/US association in what is known as the CS-preexposure effect, also known as latent inhibition and the US-preexposure effect, respectively. The chapter then explores various theories proposed to explain these effects. The chapter then delves into situations where the CS is composed of more than one stimulus, which is known as a compound stimulus, such as blocking, in which an already established CS blocks the association between a new CS with the same US, and overshadowing, in which one component of a compound CS gains more associative strength with the US than the other. The chapter also discusses theories proposed to explain the existence of this phenomenon, such as Kamin’s memory search hypothesis for blocking and the inability of one component of the compound CS to gain associative strength to the US in overshadowing.