16-6 How do our expectations, contexts, motivation, and emotions influence our perceptions?

To see is to believe. As we less fully appreciate, to believe is to see. Through experience, we come to expect certain results. Those expectations may give us a perceptual set—a set of mental tendencies and assumptions that affects, top-down, what we hear, taste, feel, and see.

Consider: Is the center image in FIGURE 16.7 below an old or young woman? What we see in such a drawing can be influenced by first looking at either of the two unambiguous versions (Boring, 1930).

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Everyday examples of perceptual set abound. In 1972, a British newspaper published unretouched photographs of a “monster” in Scotland’s Loch Ness—“the most amazing pictures ever taken,” stated the paper. If this information creates in you the same expectations it did in most of the paper’s readers, you, too, will see the monster in a similar photo in FIGURE 16.8. But when a skeptical researcher approached the original photos with different expectations, he saw a curved tree limb—as had others the day that photo was shot (Campbell, 1986). What a difference a new perceptual set makes.

Perceptual set can also affect what we hear. Consider the kindly airline pilot who, on a takeoff run, looked over at his sad co-pilot and said, “Cheer up.” Expecting to hear the usual “Gear up,” the co-pilot promptly raised the wheels—before they left the ground (Reason & Mycielska, 1982).

Perceptual set similarly affects taste. One experiment invited bar patrons to sample free beer (Lee et al., 2006). The tasters preferred the brand-name beer, even when researchers secretly added a few drops of vinegar to it—unless they had been told they were drinking vinegar-laced beer. Then they expected, and usually experienced, a worse taste. In another experiment, preschool children, by a 6-to-1 margin, thought french fries tasted better when served in a McDonald’s bag rather than a plain white bag (Robinson et al., 2007).

What determines our perceptual set? Through experience we form concepts, or schemas, that organize and interpret unfamiliar information. Our preexisting schemas for monsters and tree branches influence how we apply top-down processing to interpret ambiguous sensations.

In everyday life, stereotypes about gender (another instance of perceptual set) can color perception. Without the obvious cues of pink or blue, people will struggle over whether to call the new baby “he” or “she.” But told an infant is “David,” people (especially children) have perceived “him” as bigger and stronger than if the same infant was called “Diana” (Stern & Karraker, 1989). Some differences, it seems, exist merely in the eyes of their beholders.