Psych Chapter 6: Sensation and Perception

Terms in this set (16)

Bottom-up processing
analysis that begins with sensory receptors and works up to the brain's integration of sensory info -- body to brain/emotion; ex: smelling pickles, stomach churning, saying no thank you
Top-down processing
info processing guided by higher-level mental processes, as when we construct perceptions drawing on our experience and expectations -- brain is active first; friend offers you food, you think how nice, leads to emotions (grateful) and then bodily response (reaching out, smiling)
Transduction
conversion of one form of energy into another; in sensation, transformation of stimulus energies (sight, sound, smell) into neural impulses our brain can interpret
Absolute thresholds
minimum stimulation needed to detect a particular stimulus (light, sound, pressure, taste, odor) 50% of the time
Signal detection theory
predicts how and when we detect the presence of a faint stimulus (signal) amid background stimulation (noise); detection depends partly on a person's experience, expectations, motivation, and alertness
Subliminal
stimuli you can't detect 50% of the time; below absolute threshold for conscious awareness
Priming
activation, often unconsciously, of certain associations, thus predisposing one's perception, memory, or response
Difference threshold
minimum difference a person can detect between any two stimuli half the time; ex: if you add 1 oz to a 10-ounce weight, you will detect difference, if you add 1 oz to 100-ounce weight, you prob won't
Weber's law
for an average person to perceive a difference, two stimuli must differ by a constant proportion
Sensory adaptation
diminished sensitivity as a consequence of constant stimulation; ex: getting used to a bad smell in your friend's house

- we perceive the world not exactly as it is, but as it is useful for us to perceive it
Perceptual set
set of mental tendencies and assumptions that greatly affects (top-down) what we hear, taste, feel, see
Emotion and motivation
perceptions are influenced, top-down, by expectations and by the context, emotions and motivation
Feature detectors
nerve cells in brain that respond to specific features of the stimulus, such as shape, angle, or movement
Parallel processing
processing of many aspects of a problem simultaneously; ex: analyzing a visual scene (color, motion, form, depth)
Young-Helmholtz trichromatic theory
retina has 3 different color receptors; one most sensitive to red, to green, to blue; when stimulated in combination, can produce the perception of any color
Opponent-process theory
Three sets of opponent retinal processes enable color vision; Red-green, yellow-blue, white-black; Some cells are stimulated by green and inhibited by red
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