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The Garcia Effect

Another famous example of biologically prepared learning is taste aversion, discussed in Chapter 5. As explained there, taste aversion violates several of the old assumptions about classical conditioning. The gap between the cue (CS) and the biological response (UCR) can be very long, the aversion to a food can be learned in just one trial, and taste aversion violates the assumption of the equivalence of associations, because the illness is almost always blamed on food, even if it is due to some other factor such as a flu virus.

How does taste aversion illustrate prepared learning? What did Garcia discover in his experiments with radiation, saccharin, and red light?

The highly selective nature of food aversion is called the Garcia Effect. John Garcia showed that animals associated illness with food, even if the illness was caused by something else. If rats got sick from a dose of radiation after drinking saccharin-flavored water in a cage illuminated with red light, the rats later avoided saccharin-flavored water. But they did not avoid red light. Similarly, they got shocked after tasting the water, they learned to avoid the environment where they got shocked, but they did not learn to avoid the water.

Garcia's claim that the equivalence of associations idea was false seemed like an extraordinary claim, in the 1960s. He ran into skepticism when he tried to publish it in the prestigious journal Science. However, Garcia had extraordinarily good evidence. He documented the phenomenon in over 20 studies. He satisfied the skeptics that his findings were not a fluke or the result of methodological errors (Garcia, 1981).

What is an alternative label for "prepared learning"?

Garcia eventually received an award for his work from the American Psychological Association. The Garcia Effect became widely known and is now cited as a prime example of prepared learning or, as it is sometimes called, biological constraints on learning.


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