Pa1 Perception the extraction of meaning from sensory input not spots lines edges or wavelengths Examples Object perception what is it Object location where is it Word perception you hear sounds but are they words Wha cha doo win Pa2 Some major questions in perception What is it Object recognition the ventral stream of the visual cortex Where is it Object location in space depth the dorsal stream of visual cortex Keeping the world constant the constancies Are perceptual abilities innate or are they learned The nature nurture question Pa3 Another major question what is the relationship between sensation and perception Sensation must occur before perception occurs but how does one get from sensation to perception Does perception the sum of sensations can perception be predicted in we fully understand sensation Structuralism Titchener Wundt says yes Used method of introspection to analyze perceptions into their elementary components the sensations Functionalism James says no You cannot understand a house by understanding the bricks the elementary components of the house You must know the function of the house and its parts Darwinian influence understand behavior in terms of its functions not in terms of its basic components muscle twitches Pa4 Does perception sum of sensations contin Helmholtz say no Learned associations of sensations form the percept Unconscious inferences are used to recognize the same objects in different contexts e g a baby s hand waved across his own face is perceived as the same hand despite differing sensations Gestalt Psychologists say no The whole sum of the parts Sensations are not the basic units of perceptions Perception does not depend on learning Pa5 Gestalt contin Whole forms are be basic units of perception Whole forms are produced by a process of perceptual organization happens in the brain Perceptual organization depends upon the relationship between elements of a stimulus Figure ground relationships Laws of perceptual grouping laws of proximity closure similarity good continuation Pa6 Figure ground relationships Ambiguous figure what is figure vase or faces what is ground background The same sensation can result in different perceptions Pa7 Another ambiguous figure Is this a young woman or an old woman The stimulus is exactly the same but perceptions are different Pa8 Laws of perceptual grouping Proximity Similarity Good continuation Closure Pa9 Evidence against structuralist notions Identical sensations can yield different perceptions ambiguous figures Different sensations can yield identical constant perceptions the perceptual constancies Pa10 The perceptual constancies changing sensations can yield the same perception Shape size orientation Color brightness