Sensation: the stimulation of sense organs;
ex. involves the absorption of energy by
sensory organs
Perception: the selection, organization, and
interpretation of sensory organs; ex. organizing and
translating sensory input into something meaningful
Psychophysics
Thresholds: Looking for Limits
Absolute threshold: the minimum
amount of stimulation that an
organism can detect; i.e. as stimulus
intensity increases, subjects'
probability of responding to stimuli
gradually increases (the stimulus
intensity detected 50% of the time)
the JND (Fechner): the
smallest
difference in the
amount of
stimulation that a
specific sense
can detect
Weber's law: the size of a
JND is a constant
proportion of the size of the
initial stimulus
Fechner's law: the magnitude of a
sensory experience is proportional
to the number of JNDs that the
stimulus causing the experience is
above the absolute threshold
constant increments in stimulus
intensity produce smaller and
smaller increases in the perceived
magnitude of sensation; ex. three
bulbs of the same voltage
Signal detection theory: the
detection of a stimuli involves
decision processes as well as
sensory processes, which are
both influenced by a variety of
factors besides stimulus
intensity