Anxious : Using the Brain to Understand and Treat Fear and Anxiety by Joseph Ledoux

Author:Joseph Ledoux [Ledoux, Joseph]
Language: eng
Format: mobi
Publisher: Penguin USA
Published: 2015-06-18T04:00:00+00:00

COGNITION IN EXTINCTION

Extinction in a laboratory setting is sometimes called experimental extinction and involves relatively pure stimulus repetitions for the purpose of scientific research as opposed to treating people with anxiety. When humans are the subjects of extinction studies, there is, of course, some instruction involved, but the procedure itself is mainly based on stimulus repetition; in studies of animals, it’s stimulus repetition all the way.

When rats or people are being given stimulus repetitions in an extinction procedure, their brains are learning. Learning, including extinction learning, is a cognitive process, as it involves information processing to create internal representation of events.59 The difference between exposure and extinction is not, therefore, simply that one involves cognition and one does not. As Hofmann suggested, they both do. At the same time, although some of the cognitive processes may overlap between extinction and exposure therapy,60 others clearly differ, because there is more explicit cognition involved in the interaction between the therapist and client in exposure therapy than is typically the case when experimental participants simply undergo extinction procedures in the laboratory.

Let’s revert to the language of conditioning to discuss the contribution of cognition to extinction. The simplest view of extinction is that the CS-US association acquired during Pavlovian threat conditioning is weakened when the CS no longer predicts the US. From the purely behaviorist point of view, all that is necessary for acquisition of threat conditioning is the co-occurrence of the CS with the US, and all that is required for extinction is the repeated presentation of the CS without the US.

During the initial conditioning (CS-US pairing) the organism learns that the CS predicts the US; during extinction, it learns instead that the CS predicts the absence of the US (a “CS–no US” association is involved). In effect, as a result of extinction training, the CS comes to predict safety. For example, if you are shocked when you turn on a lamp because of a wiring defect in the switch, the lamp-shock association (a CS-US association) will cause you to avoid touching the lamp. Then, if after getting the lamp repaired you cautiously turn it on and find you are not shocked, you can proceed with abandon in using it. You’ve formed a new association—a “lamp–no shock” association (CS–no US association)—that overrides or suppresses the original association.61

With the infusion of cognitive ideas into the study of learning and memory, predictions in terms of stimulus and responses came to be supplemented with cognitive mediators.62 Specifically, the occurrence of the CS came to be thought of as triggering a “representation” of the CS-US association, such that the occurrence of the CS led to an “expectation” of the US, and it was this expectation that caused the response. Then, during extinction, the expectation established during conditioning is replaced by a new one that indicates that the CS is now safe.

For example, an influential psychological theory of conditioning by Robert Rescorla and Allan Wagner proposed that during conditioning the “surprising” (unexpected) outcome of a shock after a tone leads the brain to learn—that learning, in effect, occurs when new information is present.

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