One research study discussed in the text explained how bar patrons who consumed a free sample of brand-name, vinegar-laced beer preferred the free beer—unless they had been told about the addition of vinegar. their sense of taste had been impacted by their

Perceptual set

Explanation:

In psychology, the term "perceptual set" refers to the tendency to perceive or notice some aspects of the sensory data and ignore others.

On these cases, the person focuses his/her attention on particular aspects of the data and therefore, the other part of the data goes "unseen" and he doesn't see the complete picture.

This example refers to an study made with bar patrons who consume a free sample of beer who had been added vinegar, and others beers who weren't free. The patrons preferred the free beer (unless they had been told about the addition of vinegar). Here, they focused on the fact that this beer was free and thus, they preferred that one and their sense of taste liked that one better, their attention was focused on the free aspect of the beer and the part about the vinegar had gone unseen.

Thus, this is an example of perceptual set.