1. Introductory Psychology Concepts
Perception
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© 2011 The McGraw-Hill Companies, Inc.

2. Introductory Psychology Concepts : Perception
Giving Meaning to Sensation. The sorting out, interpretation, analysis, and integration of stimuli by the sense organs and brain.
1. Stimulus is received by sensory receptors.
Sensation
Perception

3. Introductory Psychology Concepts : Perception
Giving Meaning to Sensation. The sorting out, interpretation, analysis, and integration of stimuli by the sense organs and brain.
1. Stimulus is received by sensory receptors.
Sensation
Perception
2. Receptors translate stimulus properties into nerve impulses (transduction).

4. Introductory Psychology Concepts : Perception
Giving Meaning to Sensation. The sorting out, interpretation, analysis, and integration of stimuli by the sense organs and brain.
1. Stimulus is received by sensory receptors.
3. Feature detectors analyze stimulus features.
Sensation
Perception
2. Receptors translate stimulus properties into nerve impulses (transduction).

5. Introductory Psychology Concepts : Perception
Giving Meaning to Sensation. The sorting out, interpretation, analysis, and integration of stimuli by the sense organs and brain.
1. Stimulus is received by sensory receptors.
3. Feature detectors analyze stimulus features.
Sensation
Perception
2. Receptors translate stimulus properties into nerve impulses (transduction).
4. Stimulus features are reconstructed into neural representation.

6. Introductory Psychology Concepts : Perception
Giving Meaning to Sensation. The sorting out, interpretation, analysis, and integration of stimuli by the sense organs and brain.
1. Stimulus is received by sensory receptors.
3. Feature detectors analyze stimulus features.
5. Neural representation is compared with previously stored information in brain.
Sensation
Perception
2. Receptors translate stimulus properties into nerve impulses (transduction).
4. Stimulus features are reconstructed into neural representation.

7. Introductory Psychology Concepts : Perception
Giving Meaning to Sensation. The sorting out, interpretation, analysis, and integration of stimuli by the sense organs and brain.
1. Stimulus is received by sensory receptors.
3. Feature detectors analyze stimulus features.
5. Neural representation is compared with previously stored information in brain.
Sensation
Perception
2. Receptors translate stimulus properties into nerve impulses (transduction).
4. Stimulus features are reconstructed into neural representation.
6. Matching process results in recognition and interpretation of stimulus.

8. Introductory Psychology Concepts : Perception
Gestalt Principles of Perceptual Organization: organizing the separate parts of our perceptual field into a unified and meaningful whole
One stimulus, two perceptions
This reversible figure illustrates alternating figure-ground relations. It can be seen as a vase,or as two people facing one another.
Whichever percept exists at the moment is seen as figure against background.

9. Introductory Psychology Concepts : Perception
Gestalt Principles of Perceptual Organization
Organizing the separate parts of our perceptual field into a unified and meaningful whole.
Figure-ground relationships
Tendency to organize stimuli into a central or foreground figure and a background.
Gestalt perceptual laws
A series of principles that describe how we organize bits and pieces of information into meaningful wholes.
Gestalt is the German term for “pattern”, “whole”, or “form”.
Each principle causes us to organize stimuli into wholes that are greater than the sums of their parts.

10. Introductory Psychology Concepts : Perception
Perceptual Constancies: allowing us to recognize familiar stimuli under varying conditions
Shape constancy Allows us to recognize people and other objects from many different angles.
Brightness constancy The relative brightness of objects remains the same under different conditions of illumination (full sunlight and shade).
Size constancy Perception that the size of objects remains relatively constant even though images on our retina change in size with variations in distance.

11. Introductory Psychology Concepts : Perception
Depth Perception: translating two-dimensional information (length and width) into three-dimensional perceptions.
Monocular depth cues
(requiring only one eye):
Patterns of light and shadow
Typically used by artists to create perceptions of depth in their pictures.
Linear perspective
The perception that parallel lines converge as they recede into the distance.
Interposition
Objects closer to us may cut off part of our view of more distant objects.
Patterns of light and shadow can serve as monocular depth cues. Drawing Hands, by M.C. Escher

12. Introductory Psychology Concepts : Perception
Depth Perception: Monocular depth clues (continued)
Texture gradient
The texture or grain of an object appears finer as distance increases.
Clarity
We can see nearby hills more clearly than ones that are far away.
Relative size
Looking at two objects of similar size, the one that looks smaller will be judged to be farther away.
Height in the horizontal plane
A ship 5 miles offshore appears to be in a higher plane and closer to the horizon than does one that is only 1 mile from shore.

13. Introductory Psychology Concepts : Perception
Depth Perception: Monocular depth clues (continued)
Motion parallax
Tells us that if we are moving, nearby objects appear to move faster in the opposite direction than do far-away ones.
Like other monocular cues, motion provides us with information we can use to make judgments about distance and therefore about depth.

14. Introductory Psychology Concepts : Perception
Depth Perception: Monocular depth clues (continued)
7 monocular depth cues are used in this mural to create a 3-dimensional depth effect.
1 : Linear perspective
2 : Relative size
3 : Height in the horizontal plane
4, 5 : Texture and clarity
6 : Interposition
7 : Light and shadow 3 6 2
4,5 7 1
Mississippi River flood wall, Cape Girardeau, Missouri

15. Introductory Psychology Concepts : Perception
Depth Perception: Binocular depth cues (require both eyes):
Binocular disparity
Each eye sees a slightly different image.
Convergence
Produced by feedback from the muscles that turn your eyes inward to view a close object.
View-Master slides use the principle of binocular disparity to create the perception of depth.

16. Introductory Psychology Concepts : Perception
Factors Affecting Perception:
Top-down processing
Perception that is guided by higher-level knowledge, experience, expectations, and motivations.
Top-down processing is illustrated by the importance of context in determining how we perceive objects.
The power of context is shown in this figure. Note how the B and the 13 are identical.
(Source: Coren & Ward, 1989.)

17. Introductory Psychology Concepts : Perception
Factors Affecting Perception:
Bottom-up processing Perception that consists of the progression of recognizing and processing information from individual components of a stimuli and moving to the perception of the whole.
Top-down and bottom-up processing occur simultaneously and interact with each other in our perception of the world around us.
BOTTOM-UP PROCESSING
TOP-DOWN PROCESSING
Combination and interpretation of “whole”
Concept, Expectation
Breakdown/analysis of stimuli
Guides, analysis
Detection of individual stimulus elements
Interpretation of incoming stimuli

18. Introductory Psychology Concepts : Perception
Visual Illusions: compelling but incorrect perceptions. Physical stimuli that consistently produce errors in perception.
The Parthenon looks perfectly straight, with right angles at every corner.

19. Introductory Psychology Concepts : Perception
Visual Illusions: compelling but incorrect perceptions. Physical stimuli that consistently produce errors in perception. b.
The Parthenon looks perfectly straight, with right angles at every corner.
However, if had been built with true right angles, it would have looked as it does in figure (b).

20. Introductory Psychology Concepts : Perception
Visual Illusions: compelling but incorrect perceptions. Physical stimuli that consistently produce errors in perception. b.
The Parthenon looks perfectly straight, with right angles at every corner.
However, if had been built with true right angles, it would have looked as it does in figure (b).
To compensate for this illusion, the Parthenon was designed to have a slight upward curvature as shown in (c).
(Source: Coren & Ward, 1989, p.5.) c.