PSYC 2510 Lecture Notes - Optic Chiasm, Visual Cortex, Two-Streams Hypothesis
20 Nov 2012
School
Department
Course
Professor
Document Summary
Sensation the stimulation of sense organs (e. g. ear, taste bud) Stimulus any detectable input from the environment. Threshold - the point at which a stimulus can first be detected. As stimulus intensity goes up, the probability of responding to stimulus gradually increases. Differences in detection of stimulus in point to differences in threshold e. g. dog whistles. Absolute threshold the intensity level at which the probability of detecting stimulus is 50% under ideal conditions. Just noticeable difference (jnd) the smallest difference that can be detected between two intensity levels of a stimulus. Weber"s law the change in stimulus that will be just noticeable is a constant ratio of the original stimulus. Does not always hold for stimuli of extreme intensity. Fechner"s law the magnitude of a subjective sensation increases proportionally to the stimulus intensity, only to a certain point. Many sensory stimuli do not fit weber"s and fechner"s laws! The detection of stimuli depends on decision-making processes and sensory processes.
