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

Acquisition of the Conditional Response

In conditioning experiments, "acquisition" is basically learning. In acquisition, a creature acquires a conditional response. One lecturer-Thomas Landauer, then of Bell Laboratories in New Jersey-used a simple technique to demonstrate acquisition of a conditional response in a large introductory psychology class. While lecturing about Pavlov, he periodically raised a starter pistol, shouted "NOW!" and fired a shot.

How did Landauer establish classical conditioning, quickly, in a large crowd? What is the best timing, for conditioning of a simple motor response?

Conditioning occurs most quickly when the signal comes about half a second before the reflex is activated. This is the optimum interval to use for rapid conditioning of a simple motor response (muscle movement). Therefore, Landauer's timing was close to optimum. He shouted "NOW!" half a second before creating a loud noise that caused a startle response (made everybody jump).

It was natural that everybody jumped in reaction to the gun report. A loud noise is an unconditional stimulus (US) that leads to an unlearned startle response (UR). Five more times in the next 20 minutes of his lecture about classical conditioning Landauer raised his arm, shouted "NOW!" and fired his pistol. The sound "NOW!" was the conditional stimulus (CS). After repeating this a few times, Landauer raised his hand and shouted "NOW!" but did nothing. Everybody jumped. He had conditioned the entire crowd in less than half an hour.

Why did the students jump?

Why did this happen? The essence of classical conditioning is putting a signal before a reflex so that an organism can get a "jump" or head start on the reflex. Remember we described classical conditioning as a primitive form of prediction. Landauer's students were making an anticipatory response. After hearing "NOW!" five times, followed immediately by a gunshot, their nervous systems learned about the predictable relationship between these events. When they heard the signal again, they responded (they jumped). Of course, it was a prediction of a simple sort: they were not making a conscious plan to jump. They just did it. Classical conditioning does not require a conscious thought process.


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