Chapter 4 -- Sensation and Perception Flashcards
Sensation
When neurons in a receptor create a pattern of nerve impulses
Perception
A process that makes nerve patterns meaningful
Bottom Up Processing
Emphasize characteristics of the stimulus rather than expectations – sounding out words
Top-down processing
Emphasizes perceivers expectations memories and other cognitive factors – reading scrambled words on the 3rd slide of this powerpoint
Selective Attention
The focusing of conscious awareness on one stimulus
Cocktail Party Effect
Ability to focus attention on one audio stimulus (one conversation) among a cacophony of conversations and noise AND to attend to your own name when called
Inattentional Blindness
Failing to see visible objects when our attention is directed elsewhere
Change blindness
a change in visual stimuli goes unnoticed by the observer.
How does the brain interact with the world around
The brain senses the world indirectly because the sense organs convert stimulation into neural impulses which the brain must interpret.
Receptors
Specialized neurons activated by stimulation that perform transduction.
transduction
transformation of stimulus information into nerve impulses
Absolute threshold
amount of stimulation necessary for a stimulus to be detected
difference threshold
smallest amount a stimulus can be channged and the difference can be detected half the time AKA just noticeable difference
webers law
the JND differs by a constant minimum percentage
fechners law
increases in physical strength of a stimulus produce progressively smaller increases in perceived magnitude
difference between fechner and weber
fechner figured out the concept weber developed more intricate associated math
sensory adaptation
loss of responsiveness in receptor cells after stimulation has remained unchanged for a while
habituation
a decreased in a behavior due to repeated presentation of a stimulus occurs in the brain (it is learned) not the body
signal detection theory
a way to quantify the ability to distinguish between signal and noise emphasizes judgement and decision making processes. Experience expectation physiological state eg fatigue and other factors can affect the threshold applied.
SDT also explains hSP
SDT explains why house creaking at night doesn’t bother you if your parents are home but does when you are home alone. Applying different recognition threshold.
table signal detection theory
stimulus present response absent: miss response present: hit stimulus absent response absent: correct rejection response present: false alarm.
learning based inference
view that perception is primarily shaped by learning rather than innate factors
perceptual set
readiness to detect a particular stimulus in a given context expectations determine perception
visual system
often overrides other senses for instance the mcgurk effect. Vision can also override our sense of touch
