Perception 2

Figure 2-19 An example of context effects in perception. Top-Down Processes

The same physical stimulus can be interpreted differently depending on perceptual set, e.g., context effects. When is the middle character the letter B and when is it the number 13? Perceptual Set Context Effects

Top-Down Processes Perceptual Learning

Top-Down Processes Change Blindness

Word Superiority Effect Top-Down Processes K OWRK WORK K D

Bottom-Up and Top-Down Processing working together Word Perception Connectionist Model Features (lines) Letters Words I B Bat _at Flying Animal

Figure 2-24 (p. 73) Example of stimuli used in the PET scan study of processing words. See text for explanation. Word Perception Neuropsychological Perspective

Direct Perception vs. Constructivist Approach Biological motion lab/eng_p/e051c1m1_curr.html lab/eng_p/e051c1m1_curr.html

Optic flow

Affordances:  Information from the stimulus that specifies how it can be used Direct Perception

(Ventral) (Dorsal)

Visual Agnosia

Visual Agnosia Associative Visual Agnosia  Can copy, but unaware what it is; cannot assign meaning to object  Difficulty in transferring visual info into words Apperceptive Visual Agnosia  Cannot recognize by shape  Cannot copy drawings  Often involves ‘prosopagnosia’

Agnosia

Identification of Faces and Members of Categories Prosopagnosia The Fusiform Face Area:

Thatcher illusion

Subliminal Perception Can subliminal messages change our behaviors?