2.1 sensation and perception Flashcards
sensation
the transduction/conversion of physical, electromagnetic, auditory, and other information from our internal and external environment to electrical signals in the nervous system; performed by receptors in the PNS
perception
processing of information to make sense of its significance
sensory receptors
neurons that response to stimuli and trigger electrical signals
distal stimuli
stimuli that originate outside of the body; the source of stimuli that reach our receptors; ex. A campire is a distal stimulus
proximal stimuli
stimuli that directly interact with and affect the sensory receptors; inform the observer of the presence of distal stimuli; ex. photons and heat
psychophysics
the field that studies the relationship between the physical nature of stimuli and the sensations and perceptions they evoke
ganglia
collections of neuron cell bodies found outside the CNS; connect information from receptors and deliver it to the CNS?
projection areas
a portion of the cerebral cortex that analyzes sensory input
threshold
the minimum amount of a stimulus that renders a difference in perception
absolute threshold
the minimum of stimulus energy that is needed to activate the sensory system; a stimulus below this threshold will not be transduced and never reach the CNS
threshold of conscious perception
a stimulus arrives at the CNS but does not reach the higher-order brain regions that control attention and consciousness
limina
another word for thresholds
subliminal perception
often refers to the perception of a stimulus below a given threshold; usually referse to the threshold of CONSCIOUS perception
psychophysical discrimination testing
a participant is presented with a stimulus that is varied slightly and asked to identify if there was a difference; the difference is increased until the participant notices the change
difference threshold (JND)
the minimum difference in magnitude between two stimuli before one can perceie this difference
Weber’s Law
there is a constant ratio between the change in stumulus magnitude needed to produce a JND and the magnitude of the original stimulus; for higher magnitude stimuli, the difference must be larger to produe a JND
signal detection theory
the changes in our perception of the same stimuli depending on both internal and external context
response bias
the tendency of subjects to systematically respond to a stimulus in a particular way due to nonsensory factors
signal detection experiment
each trial, a stimulus/signal may or may not be presented; that participany indicates whether or not they believe a signal was given
signal detection experiment: catch trials
a trial where a stimulus is presented
signal detection experiment: noise trials
a trial where a stimulus is not presented
signal detection experiment: hit
person says there was a signal when there WAS one
signal detection experiment: miss
person fails to indicate a signal when there WAS one
signal detection experiment: false alarm
person says there was a signal when the WASN’T one
signal detection experiment: correct negative
person doesn’t indicate a signal when there was no signal
adaptation
a decrease in stimulus perception after being exposed to it for a long time; a way that that mind attempts to focus on the most relevent stimuli, which are usually CHANGES in the environment
