TopDown versus BottomUp Perception TopDown Perceive the whole
Top-Down versus Bottom-Up Perception • Top-Down – Perceive the whole and then individual parts as needed. – Experience-driven as opposed to stimulus or inputdata driven. – Quick and highly inferential but also a source of misperception. • Bottom-up – Perceive the individual parts and organize them into a whole, if possible. – Information available in the stimulus itself. Arranged by Dr. Gordon Vessels 2005
Bottom-Up Processing Prior Knowledge, Experience, etc. Perception Stimuli Processing Stimuli Input Created by Dr. Gordon Vessels 2005
Gregory on Top-Down Perception • Gregory proposes that we use our prior “experience of the world to shape how we perceive” stimuli we encounter in it. • His theory of perception is called Top-Down, • Which means we use activated conceptual schemas and memory networks (our stored knowledge), more or less automatically and subconsciously, to shape our perceptions or to interpret our sensory input ― sometimes correctly and sometimes not. • He confirmed many of his theoretical propositions using visual illusion research. Primary source Bell, Vaughan (2004). Perceptions and perceptual distortions, a PPT show accessed at http: //www. cf. ac. uk/psych/home/bellv 1/conf/Vaughan. Perception. Lecture 2004. ppt#1. Written permission granted 5 -5 -05.
Top-Down Processing Culture Social Class Personality Temperament Values Beliefs Prejudices Attitudes Occupation Education Prior Knowledge, Experience, etc. Prior Stimuli Perceived Present Fatigue Energy Level Needs, Moods Mental Health Long-term Memory Schemas Specific Life Experiences Perception Stimuli Processing Stimuli Input Created by Dr. Gordon Vessels 2005 Immediate Mental Set Presence of Authority Knowledge Vocabulary
If all of these people were at the same football game, who among them was most likely to have perceived what actually happened on a controversial play where the receiver may have fumbled the ball before his knees touched the ground? Whose perceptions were the most bottom up? Whose perceptions were the most top-down and thus influenced and quickened in terms of inference by their present needs, biases, and heightened emotion? Whose perception may have been the most accurate and objective based on his or her knowledge of the game? When the head referee reviewed the replays, did he use topdown or bottom-up perception primarily? What top-down influence may have made it possible for his perceptions to have been highly accurate? Did these people literally see something different? Do they really believe what they claimed to have seen?
What do you see? The word liar in script or cursive? A face looking down? Those shown artwork with faces were more inclined than others to see the word liar. What do you see? A face looking down? The word Liar in script or cursive? Those who first read stories about deception were more inclined than others to see the word Liar. Arranged by Dr. Gordon Vessels 2004
Top-Down & Bottom-Up Processing Prior Knowledge, Experience, etc. Perception Stimuli Processing Stimuli Input Created by Dr. Gordon Vessels 2005
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