SENSATION PERCEPTION ATTENTION
SENSATION: how sense organs detect and respond to energy from external stimuli,
as well as how these responses are transmitted to the brain.
PERCEPTION: these signals are further processed. Understanding perception
requires an understanding of sensory processes.
Perceptual Constancy: we know snow is white and a tire is black, even snow at
night and a tire in really bright light (even if they send identical luminance cues) a
door is a rectangle even though we rarely, if ever, see 4 right angles projected onto our
retina. There is size constancy, shape constancy, colour constancy, lightness constancy.
We need to understand the relationship between at least two factors (how far the
object is from us, how much light is reflecting off the surface, etc) in order to
understand what we are seeing.
**THE BRAIN COMPUTES A RATIO BASED ON RELATIVE MAGNITUDE
RATHER THAN ABSOLUTE MAGNITUDE OF EACH SENSATION**
Classic Perceptual Theory:
Perceptual experience& (maybe) innate knowledge info about ratio relationships
that determine CONSTANCIES.
Sensations impulsesbraininterprets according to previous learning/evolution.
“visual perception is ALWAYS based on unconscious inferences”
Stimuli provide information in themselves & we are hardwired to interpret visual
cues in ways that benefit survival.
We don’t need addit.l memories, calculations or inferences to understand sensory
***Helmholtz is right***
ATTENTION: How the brain selects which sensory stimuli to discard, and which to
pass along to higher levels of processing.
Binding: since the brain processes features automatically & separately,
attention helps us to bind features together in order to determine that certain
features belong to a certain object.
Selective Attention: filtering attention pay attention to only 1 thing.