Objectives: To develop an understanding of Perception in relation to psychology Question: How might you psychologically explain this: David Rosenhan and some of his colleagues were admitted as patients to various mental hospitals with “diagnoses” of schizophrenia Once inside, they acted normal but the staff members only saw what they expected to see and not what was actually occurring The real patients were the first to realize that the psychologists were not really mentally ill

Perception The process of organizing and interpreting information, enabling us to recognize meaningful objects and events.

Perceptual Ideas

Top-Down Processing We perceive by filling the gaps in what we sense. I _ant ch_co_ate ic_ cr_am. Based on our experiences and schemas. If you see many old men in glasses, you are more apt to process a picture of an old man (even when you may be in error).

Bottom-Up Processing Also called feature analysis. We use the features on the object itself to build a perception. Takes longer than top-down but is more accurate.

Figure Ground Relationship Our first perceptual decision is to decide what the image is (the figure) and what the background is (the ground).

Gestalt Philosophy The whole is greater than the sum of its parts

Gestalt Psychology Gestalt psychologists focused on how we GROUP objects together. We innately look at things in groups and not as isolated elements. Proximity (group objects that are close together as being part of same group) Similarity (objects similar in appearance are perceived as being part of same group) Continuity (objects that form a continuous form are perceived as same group) Closure (like top-down processing…we fill gaps in if we can recognize it)

Constancy Objects change in our eyes constantly as we or they move….but we are able to maintain constant perception Shape Constancy Size Constancy Brightness Constancy

Perceived Motion Stroboscopic effect (flip book effect) Phi phenomenon Autokinetic Effect (if people stare at a white spotlight in a dark room, it appears to move.)

Depth Perception The ability to see objects in three dimensions although the images that strike the retina are two dimensional. Allows us to judge distance.

Depth Cues Eleanor Gibson and her Visual Cliff Experiment. If you are old enough to crawl, you are old enough to see depth perception. We see depth by using two cues that researchers have put in two categories: Monocular Cues Binocular Cues

Monocular Cues You really only need one eye to use these (used in art classes to show depth). Linear Perspective Interposition Relative size Texture gradient Shadowing

Monocular Cues Interposition: if something is blocking our view, we perceive it as closer. Relative Size: if we know that two objects are similar in size, the one that looks smaller is farther away. Relative Clarity: we assume hazy objects are farther away.

More Monocular Cues Texture Gradient: the coarser it looks the closer it is. Relative Height: things higher in our field of vision look farther away Relative Motion: things that are closer appear to move more quickly. Liner Perspective: Parallel lines seem to converge with distance. Light and Shadow: Dimmer objects appear farther away because they reflect less light.

Binocular Cues We need both of our eyes to use these cues. Retinal Disparity (as an object comes closer to us, the differences in images between our eyes becomes greater. Convergence (as an object comes closer, our eyes have to come together to keep focused on the object).

Extrasensory Perception (ESP): Fact or Fallacy? Parapsychology: Study of ESP and other psi phenomena (events that seem to defy accepted scientific laws) Clairvoyance: Purported ability to perceive events unaffected by distance or physical barriers Telepathy: Purported ability to read minds Precognition: Purported ability to accurately predict the future (“Minority Report” and the “Pre- Cogs,” like Agatha) Psychokinesis (Mind Over Matter): Purported ability to influence physical objects by willpower

More ESP Issues Run of Luck: Statistically unusual outcome that could occur by chance alone (e.g., getting five heads in a row, two jackpots within six pulls of a slot machine) Stage ESP: Simulation of ESP for entertainment purposes Conclusion: Existence of ESP has NOT been scientifically demonstrated; positive results are usually inconclusive and easily criticized In sum: Be skeptical! If it seems too good to be true, it probably is!

Fig Fake psychokinesis. (a) The performer shows an observer several straight keys. While doing so, he bends one of the keys by placing its tip in the slot of another key. Normally, this is done out of sight, behind the “psychic’s” hand. It is clearly shown here so you can see how the deception occurs. (b) Next, the “psychic” places the two keys in the observer’s hand and closes it. By skillful manipulation, the observer has been kept from seeing the bent key. The performer then “concentrates” on the keys to “bend them with psychic energy.” (c) The bent key is revealed to the observer. “Miracle” accomplished! (Adapted from Randi, 1983.) (a) (b c)