AP Psychology

Module 17 - Influences on Perception

LEARNING OBJECTIVES:

Perceptual Set

FOCUS QUESTION: How do our expectations, contexts, emotions, and motivation influence our perceptions?

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

As everyone knows, 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 greatly affects (top-down) what we perceive. Perceptual set can influence what we hear, taste, feet and see.

Consider: Is the image in the center picture of FIGURE 17.1 a young woman's profile or an old woman? What we see in such a drawing can be influenced by first looking at either of the two unambiguous versions (Boring, 1930).

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 17.2. But when a skeptical researcher approached the photos with different expectations, he saw a curved tree limb - as had others the day the photo was shot (Campbell, 1986). With this different perceptual set, you may now notice that the object is floating motionless, with ripples outward in all directions - hardly what we would expect of a lively monster. Once we have formed a wrong idea about reality, we have more difficulty seeing the truth.

Perceptual set can also affect what we hear. Consider the kindly airline pilot who, on a takeoff run, looked over at his depressed 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 some bar patrons to sample free beer (Lee et a1., 2006). When researchers added a few drops of vinegar to a brand-name beer, the tasters preferred 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 a1., 2007).

What determines our perceptual set? As Module 47 will explain, through experience we form concepts, or schemas, that organize and allow us to interpret unfamiliar information. Our pre - existing schemas for old women and young women, for monsters and tree limbs, all influence how we interpret ambiguous sensations with top-down processing.

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) may perceive "him" as bigger and stronger than if the same infant is called "Diana" (Stern & Karraker, 1989). Some differences, it seems, exist merely in the eyes of their beholders.

Context Effects

A given stimulus may trigger radically different perceptions, partly because of our differing perceptual set, but also because of the immediate context. Some examples:

Emotion and Motivation

Perceptions are influenced, top-down, not only by our expectations and by the context, but also by our emotions and motivation.

Hearing sad rather than happy music can predispose people to perceive a sad meaning in spoken homophonic words - mourning rather than morning, die rather than dye, pain rather than pane (Halberstadt et a1., 1995).

Researchers (Proffitt, 2006a,b; Schnall et al., 2008) have demonstrated the power of emotions with other clever experiments showing that

Even a softball appears bigger when you are hitting well, observed other researchers, after asking players to choose a circle the size of the ball they had just hit well or poorly (Witt & Proffitt, 2005). When angry, people more often perceive neutral objects as guns (Bauman & DeSteno, 2010).

Motives also matter. Desired objects, such as a water bottle when thirsty, seem closer (Balcetis & Dunning, 2010). This perceptual bias energizes our going for it. Our motives also direct our perception of ambiguous images.

Emotions color our social perceptions, too. Spouses who feel loved and appreciated perceive less threat in stressful marital events - "He's just having a bad day" (Murray et a1., 2003). Professional referees, if told a soccer team has a history of aggressive behavior, will assign more penalty cards after watching videotaped fouls Gones et al., 2002).

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Emotion and motivation clearly influence how we perceive sensations. But what to make of extrasensory perception, which claims that perception can occur apart from sensory input? For more on that question, see Thinking Critically About: ESP - Perception Without Sensation?

Before You Move On

ASK YOURSELF: Can you recall a time when your expectations have predisposed how you perceived a person (or group of people)?

TEST YOURSELF: What type of evidence shows that, indeed, "there is more to perception than meets the senses"?

Thinking Critically About

ESP - Perception Without Sensation?

What are the claims of ESP, and what have most research psychologists concluded after putting these claims to the test?

Without sensory input, are we capable of extrasensory perception (ESP)? Are there indeed people - any people - who can read minds, see through walls, or foretell the future? Nearly half of Americans believe there are (AP, 2007; Moore, 2005).

The most testable and, for this unit, most relevant parapsychological concepts are

Closely linked is psychokinesis, or "mind over matter," such as levitating a table or influencing the roll of a die. (The claim is illustrated by the wry request, "Will all those who believe in psychokinesis please raise my hand?")

If ESP is real, we would need to overturn the scientific understanding that we are creatures whose minds are tied to our physical brains and whose perceptual experiences of the world are built of sensations. Sometimes new evidence does overturn our scientific preconceptions. Science, as we will see throughout this book, offers us various surprises - about the extent of the unconscious mind, about the effects of emotions on health, about what heals and what doesn't, and much more.

Most research psychologists and scientists - including 96 percent of the scientists in the U.S. National Academy of Sciences - are skeptical that paranormal phenomena exist (McConnell, 1991). But reputable universities in many locations, including Great Britain, the Netherlands, and Australia, have added faculty chairs or research units in parapsychology (Turpin, 2005). These researchers perform scientific experiments searching for possible ESP and other paranormal phenomena. Before seeing how parapsychologists do research on ESP, let's consider some popular beliefs.

PREMONITIONS OR PRETENSIONS?

Can psychics see into the future? Although one might wish for a psychic stock forecaster, the tallied forecasts of "leading psychics" reveal meager accuracy. During the 1990s, the tabloid psychics were all wrong in predicting surprising events. (Madonna did not become a gospel singer, the Statue of Liberty did not lose both its arms in a terrorist blast, Queen Elizabeth did not abdicate her throne to enter a convent.) And the new - century psychics have missed the big - news events. Where were the psychics on 9/10 when we needed them? Why, despite a $50 million reward offered, could none of them help locate terrorist Osama bin Laden after the horror of 9/11 , or step forward to predict the impending stock crashes in 2008? In 30 years, unusual predictions have almost never come true, and psychics have virtually never anticipated any of the year's headline events (Emory, 2004, 2006). In 2010, when a mine collapse trapped 33 miners, the Chilean government reportedly consulted four psychics. Their verdict? "They're all dead" (Kraul, 2010). But 69 days later, all 33 were rescued. Moreover, the hundreds of psychic visions offered to police departments have been no more accurate than guesses made by others (Nickell, 1994, 2005; Radford, 2010; Reiser, 1982). But their sheer volume does increase the odds of an occasional correct guess, which psychics can then report to the media. Police departments are wise to all this. When researchers asked the police departments of America's 50 largest cities whether they ever had used psychics, 65 percent said No (Sweat & Durm, 1993). Of those that had, not one had found them helpful. Vague predictions can also later be interpreted ("retrofitted") to match events that provide a perceptual set for "understanding" them. Nostradamus, a sixteenth - century French psychic, explained in an unguarded moment that his ambiguous prophecies "could not possibly be understood till they were interpreted after the event and by it."

Are the spontaneous "visions" of everyday people any more accurate? Do dreams, for example, foretell the future, as people from both Eastern and Western cultures tend to believe - making some people more reluctant to fly after dreaming of a plane crash (Morewedge & Norton, 2009)? Or do they only seem to do so when we recall or reconstruct them in light of what has already happened? Two Harvard psychologists tested the prophetic power of dreams after superhero aviator Charles Lindbergh's baby son was kidnapped and murdered in 1932, but before the body was discovered (Murray & Wheeler, 1937). When invited to report their dreams about the child, 1300 visionaries submitted dream reports. How many accurately envisioned the child dead? Five percent. And how many also correctly anticipated the body's location - buried among trees? Only 4 of the 1300. Although this number was surely no better than chance, to those 4 dreamers the accuracy of their apparent precognitions must have seemed uncanny.

Given the billions of events in the world each day, and given enough days, some stunning coincidences are sure to occur. By one careful estimate, chance alone would predict that more than a thousand times a day someone on Earth will think of another person and then within the next five minutes will learn of that person 's death (Charpak & Broch, 2004). Thus, when explaining an astonishing event, we should "give chance a chance" (Lilienfeld, 2009). With enough time and people, the improbable becomes inevitable.

PUTTING ESP TO EXPERIMENTAL TEST

When faced with claims of mind reading or out-of-body travel or communication with the dead, how can we separate bizarre ideas from those that sound strange but are true? At the heart of science is a simple answer: Test them to see if they work. If they do, so much the better for the ideas. If they don't, so much the better for our skepticism.

This scientific attitude has led both believers and skeptics to agree that what parapsychology needs is a reproducible phenomenon and a theory to explain it. Parapsychologist Rhea White (1998) spoke for many in saying that "the image of parapsychology that comes to my mind, based on nearly 44 years in the field, is that of a small airplane [that] has been perpetually taxiing down the runway of the Empirical Science Airport since 1882 ... its movement punctuated occasionally by lifting a few feet off the ground only to bump back down on the tarmac once again. It has never taken off for any sustained flight."

How might we test ESP claims in a controlled, reproducible experiment? An experiment differs from a staged demonstration. In the laboratory, the experimenter controls what the "psychic" sees and hears. On stage, the psychic controls what the audience sees and hears.

The search for a valid and reliable test of ESP has resulted in thousands of experiments. After digesting data from 30 such studies, parapsychologist Lance Storm and his colleagues (2010a,b) concluded that, given participants with experience or belief in ESP, there is "consistent and reliable" parapsychological evidence. Psychologist Ray Hyman (2010), who has been scrutinizing parapsychological research since 1957, replies that if this is the best evidence, it fails to impress: "Parapsychology will achieve scientific acceptability only when it provides a positive theory with … independently replicable evidence. This is something it has yet to achieve after more than a century."

Daryl Bem (2011), a respected social psychologist, has been a skeptic of stage psychics; he once quipped that "a psychic is an actor playing the role of a psychic" (1984). Yet he has reignited hopes for replicable evidence with nine experiments that seemed to show people anticipating future events. In one, when an erotic scene was about to appear on a screen in one of two randomly selected positions, Cornell University participants guessed right 53.1 percent of the time (beating 50 percent by a small but statistically significant margin). In another, people viewed a set of words, took a recall test of those words, and then rehearsed a randomly selected subset of those words. People better remembered the rehearsed words - even when the rehearsal took place after the recall test. The upcoming rehearsal - a future event - apparently affected their ability to recall words.

Bem wonders if his "anomalous" findings reflect an evolutionary advantage to those who can precognitively anticipate future dangers. Critics scoff. "If any of his claims were true," wrote cognitive scientist Douglas Hofstadter (2011), "then all of the bases underlying contemporary science would be toppled, and we would have to rethink every1hing about the nature of the universe." Moreover, if future events retroactively affect present feelings, then why can't people intuitively predict casino outcomes or stock market futures?

Despite Bem's research having survived critical reviews by a top - tier journal, other critics found the methods "badly flawed" (Alcock, 2011) or the statistical analyses "biased" (Wagenmakers et al., 2011). "A result - especially one of this importance - must recur several times in tests by independent and skeptical researchers to gain scientific credibility," observed astronomer David Helfand (2011). "I have little doubt that Professor Bem's experiments will fail this test."

Anticipating such skepticism, Bem has made his computer materials available to anyone who wishes to replicate his studies, and replications are now under way. One research team has already conducted five replications of Bem's recall experiments at various universities and found no precognition (Galak et al., 2011) . Regardless of the outcomes, science will have done its work. It will have been open to a finding that challenges its own worldview, and then, through follow - up research, it will have assessed its validity. And that is how science sifts crazy - sounding ideas, leaving most on the historical waste heap while occasionally surprising us.

One skeptic, magician James Randi, has had a longstanding offer of $1 million to be given "to anyone who proves a genuine psychic power under proper observing conditions" (Randi, 1999; Thompson, 2010). French, Australian, and Indian groups have made similar offers of up to 200,000 euros (eFI, 2003). Large as these sums are, the scientific seal of approval would be worth far more. To refute those who say there is no ESP, one need only produce a single person who can demonstrate a single, reproducible ESP event. (To refute those who say pigs can't talk would take but one talking pig.) So far, no such person has emerged.

Before You Move On

ASK YOURSELF: Have you ever had what felt like an ESP experience? Can you think of an explanation other than ESP for that experience?

TEST YOURSELF: What is the field of study that researches claims of extrasensory perception (ESP)?