Transcript What is the Relationship Between Perception and Sensation?
I CAN: Explain the Relationship Between Perception and Sensation?
Perception brings meaning to sensation
, so perception produces an interpretation of the external world, not a perfect representation of it Copyright © Allyn and Bacon 2006
What is the Relationship Between
Perception
and
Sensation
?
Percept : What
we perceive
The meaningful product of perception –often an image that has been associated with
concepts, memories, emotions, and motive
The primary goal of perception is to get an accurate ‘fix’ on the world – to recognize friends, foes, opportunities, and dangers.
Copyright © Allyn and Bacon 2006
The first step in Perception is Attention
• We sense 11,000,000 bits of information per second.
• We consciously only process about 40 bits (Wilson 2002).
• The process by which we attend to these bits is called selective attention • Selective Attention can miss things!
The Machinery of
Perceptual Processing
•
Feature Detectors
Cells in the cortex that specialize in extracting certain features of a stimulus •
Binding Problem
The physical processes used by the brain to combine many aspects of sensation to a single percept •
Example: Recognizing a face
•
This is one of the major unsolved mysteries in psychology
Bottom-Up and Top-Down Processing •
Bottom-Up Processing
Analysis that stress features of the stimulus, rather than internal concepts • Example: Noticing a flower in a field • If your attention is drawn to a flower in a field, it may be simply that the flower is more visually outstanding than the surrounding field….you didn’t have to think about it
Bottom-Up Processing
• In bottom-up processing, the resulting percept is determined by
stimulus features
.
– Color, size, shape…
Bottom-Up and Top-Down Processing
•
Top-Down Processing
• --Expectations --Memories --Knowledge --Cultural background --and other cognitive factors ….influence perception
Top-Down Processing
• Top-down processing is also known as
conceptually driven processing.
•
Top-down does not emphasize stimulus features
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• Even though the second letter in each word is ambiguous, top down processing allows for easy disambiguation based on the context.
Top-Down Processing
• Your dog has been lost for three days, and you cannot stop thinking about him. • When you hear a dog bark, you assume that it is your dog.
Perception Experiment
• Group A- tables along hallway • Group B- tables along windows
Group A
• You are going to look briefly at a picture and then answer some questions about it. The picture is a rough sketch of a poster for a costume ball. Do not dwell on the picture. Look at it only long enough to “take it all in” once. After this, you will answer YES or NO to a series of questions.
Group B
• You are going to look briefly at a picture and then answer some questions about it. The picture is a rough sketch of a poster for a trained seal act. Do not dwell on the picture. Look at it only long enough to “take it all in” once. After this, you will answer YES or NO to a series of questions.
Picture
In the picture was there . .
1.
2.
3.
A car?
A man?
A woman?
4.
5.
6.
7.
8.
A child?
An animal?
A whip?
A sword?
A man’s hat?
9.
A ball?
10. A fish?
Conclusion
• Top Down processing – you go beyond the sensory information to try to make meaning out of ambiguity in your world • What you expect (your experiences and your perceptual set) drives this process • Today we will see what expectations we all have in common.
Perceptual Constancy
A dog is running at you – you don’t perceive it as growing larger
Copyright © Allyn and Bacon 2006
•
Shape Consistency:
Explains why we do not see people morphing in shape as they walk past us and we see them from a different perspective.
•
Color Consistency:
Explains why a shirt will look the same shade of blue in dim light or sunlight Copyright © Allyn and Bacon 2006