This is the 2007 version. Click here for the 2017 chapter 05 table of contents.

Why Classical Conditioning Evolved

Classical conditioning is simple, but it was a major advance for creatures on Earth, because in its own humble way it is aprediction of the future. The sea slug senses the odor of food, and extends its feeding tube even before food is encountered. This trick enables the clever sea slug to feed quickly and consume more food than its less learned cousins who wait until they bump into food before responding to it. So the clever sea slug lives well and reproduces, and its descendants take over the seas.

How might the sea slug gain an advantage by making a response early?

Classical conditioning occurred in simple animals, and continues to occur in humans, because any animal can benefit from making anticipatory reactions. All animals need to prepare for the future. Creatures like the sea slug follow the simplest rule: "If it happened before, it may happen again." After A is paired with B a few times, A is treated as though A predicts B.

How does classical conditioning relate to the "head vs. heart" distinction discussed in Chapter 3?

Because it is so simple and basic, classical conditioning does not require conscious thinking or language. It can influence people-or sea slugs-without a conscious thought process. We hinted at this in Chapter 3 (States of Consciousness) when discussing the distinction between two modes of processing in human mental life. Different labels are used to describe the two modes: serial vs. parallel processing, intellectual vs. emotional processing, head vs. heart, analytic vs. intuitive thought, conscious vs. unconscious thought, and so forth. Classical conditioning comes down squarely on the "parallel, emotional, heart, intuitive, unconscious" side. The effects of classical conditioning are automatic. They tend to involve emotional processes rather than intellectual processes. They are involuntary rather than a result of will power.

This distinction proves to be important when discussing the applications of classical conditioning to psychotherapy. Almost by definition, people requesting therapy are facing an unpleasant emotional reaction they cannot control simply by wishing it away or exercising conscious effort. That is why they seek help. In almost every case, the unpleasant emotional reaction can be analyzed as a case of classical conditioning. That will be a prominent theme in later parts of this chapter, as well as Chapter 13 (Therapies).

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