Sensation and Perception part 4 Chapter 4 November 2014

Perception Perception is the process of assembling sensory information so that we can understand what the incoming energy means A matter of interpretation and expectation

Perceptual Constancies “Constancy” = holding steady Perceptual constancies are what we must do to make sense of our environments

Perceptual Constancies Size Constancy – the ability to retain the size of an object regardless of where it is located. Skill appears in infants only a couple of weeks old

Perceptual Constancies This scene depicts a larger man chasing a smaller man …Or does it? The two men are absolutely identical What you see is not always what you perceive

Perceptual Constancies Expectations can allow humans to be tricked by the size constancy For example, these 3 men are the same height

Perceptual Constancies Color Constancy – The ability to perceive an object as the same color regardless of environment (lighting) Only works when we already know what color something is (i.e., the expectation exists)

Perceptual Constancies Expectations allow you to perceive fruit as having correct color, despite change in lighting But you can still be tricked:

Perceptual Constancies Brightness Constancy – by taking an average, the human visual network keeps brightness constant as an object is moved to various environments Rods and cones adjust to compensate for change in lighting e.g. when you step outside from a dark indoor space on a sunny day, some of the visual nerve cells shut off to keep the colors looking the same in bright light.

Perceptual Constancies

Perceptual Constancies Space Constancy – the ability to keep objects in the environment steady

Perceptual Constancies Paul Cezanne

Perceptual Constancies

Perception Depth Perception – the ability to see objects in space Visual Cliff – a large table with plexiglas, used to demonstrate depth perception in small children. https://www.youtube.com/watch?v=3WvtEFJGp-8

Perception Binocular Disparity – The difference between the image provided by each eye. When the images are brought together in the brain, they provide a sense of depth.

Perception Visual Texture – depth perception based on how rough or smooth objects appear.

Perception

Perception

Perceptual Organization Gestalt – organized whole shape or form Gestalt Psychologists found humans use perceptual cues to make sense of things Similarity – a perceptual cue in which we group things together Closure – the process of filling in the missing details of what is viewed. Proximity – the perceptual cue in which we group together things that are near one another

Perceptual Organization Similarity – a perceptual cue in which we group things together

Perceptual Organization Closure – the process of filling in the missing details of what is viewed e.g. when we retell a story we’ve heard but can’t recall the details, we may tend to fill in the gaps to make the story seem whole.

Perceptual Organization Proximity – a perceptual cue in which we group together things that are near one another

Illusions Illusion – an inaccurate perception Muller-Lyer Illusion – two pictures in which one line seems longer than the other but really isn’t.

Illusions Reversible figure – an illusion in which the same object is seen as two alternating figures – first one, then the other.

Subliminal Perception Subliminal perception – Stimulation presented below the level of consciousness Tapes to help you quit smoking, control weight increase self-esteem claim to use subliminal perception “EAT POPCORN” Advertisement at movie theater in 1950’s supposedly increased popcorn sales by 50% http://www.youtube.com/watch?v=kCdPpJjvLck

Extrasensory Perception (ESP) Extrasensory perception – receiving information without aid of the “normal” five senses You get a feeling you should call someone, and upon calling them, find out they are sick, for example. Several studies have shown ESP is possible, but not consistent, which makes it difficult to study. Another problem is that most ESP demonstrations are fake

Extrasensory Perception (ESP) Types of extrasensory perception: Telepathy– reading someone’s mind Clairvoyance – seeing or knowing something without being there Precognition – predicting the future Psychokinesis – moving objects with your brain * No scientific evidence to prove psychokinesis exists http://www.youtube.com/watch?v=8-Aeyej5asw