Hockenbury Discovering Psychology 5th txtbk

128 CHAPTER 3 Sensation and PerceptionThe $28,000 Grilled Cheese Sandwich:What Do You See? Is that MarleneDietrich on that grilled cheese sandwich?Ten years after she first noticed what shethought was the face of the Virgin Maryon her grilled cheese sandwich (left),Diana Duyser auctioned it off on eBay. Thewinning bid? Duyser got $28,000 for hercarefully preserved (and partially eaten)relic. Donna Lee, however, only made apaltry $1,775 for her pirogi, a type of Polishdumpling, which she believes bears theface of Jesus. (We think it looks like Al Pacino. . . or Abraham Lincoln.) Why are weso quick to perceive human faces in ambiguousstimuli?to reasonably accurate conclusions. If they didn’t, we would develop new perceptualsets that were more accurate. But sometimes a perceptual set can lead usastray. For example, someone with an avid interest in UFOs might readily interpretunusual cloud formations as a fleet of alien spacecraft. Sightings of Bigfoot,mermaids, and the Loch Ness monster that turn out to be brown bears, manatees,or floating logs are all examples of perceptual set.People are especially prone to seeing faces in ambiguous stimuli, as in the photosshown above. Why? One reason is that the brain is wired to be uniquely responsiveto faces or face-like stimuli. Research by Doris Tsao (2006a, 2006b) showed thatthe primate brain contains individual brain neurons that respond exclusively to facesor face-like images. This specialized face recognition system allows us to identify anindividual face out of the thousands that we can recognize (Kanwisher, 2006).But this extraordinary neural sensitivity also makes us more liable to false positives,seeing faces that aren’t there. Vague or ambiguous images with face-likeblotches and shadows can also trigger the brain’s face recognition system. Thus, wesee faces where they don’t exist at all—except in our own minds.“By getting some sight, Igained some new elementsof my personalityand lifestyle without rejectingthe blindness. Iam not a blind person ora sighted person. I amnot even simply a visuallyimpaired person. I amMike May with his quirkysense of humor, grayinghair, passion for life, andrather unusual combinationof sensory skills.”>> Closing ThoughtsFrom reflections of light waves to perceptual illusions, the world you perceive isthe result of a complex interaction among distinctly dissimilar elements—environmental stimuli, sensory receptor cells, neuralpathways, and brain mechanisms. Equally importantare the psychological and cultural factors that helpshape your perception of the world. As Mike’s story illustrated,the world we experience relies not only onthe functioning of our different sensory systems butalso on neural pathways sculpted by years of learningexperiences from infancy onward.Although he spent more than four decades totallyblind, Mike never seemed to lack vision. With conviction,humor, and curiosity, he sought out a life ofchange and adventure. And he found it. Rather thanexpecting his surgery to fundamentally change his life,he simply welcomed the opportunity for new experiences.Throughout his life, Mike wrote, “I have sought