1. Sensation and Perception part 4
Chapter 4
November 2014

2. 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

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

4. 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

5. 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

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

7. 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)

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

9. 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.

10. Perceptual Constancies

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

12. Perceptual Constancies
Paul Cezanne

13. Perceptual Constancies

14. 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.

15. 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.

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

17. Perception

18. Perception

19. 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

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

21. 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.

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

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

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

25. 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%

26. 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

27. 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