PSYC 2000 Lecture Notes - Lecture 2: Habituation, Retina, Cornea
Document Summary
Thresholds: absolute threshold: minimum stimulation needed to detect a particular stimulus 50% of the time, detection. Difference threshold: difference threshold: min. difference between 2 stimuli required for detection 50% of the time, also called just noticeable difference (jnd). We(cid:271)er"s la(cid:449: in humans, difference thresholds (experienced as a just noticeable difference) increase in proportion to the size of the stimulus, 2 stimuli must differ by a constant min. percentage (rather than a constant amt. ), to be perceived as different: weber fraction: k = i/i, suppose you presented two light bulbs each with an intensity of 100 units to an observer. 8/100 = . 08: you can now predict the difference threshold needed for a light bulb of any other intensity value. Habituation: the tendency of the brain to stop attending to constant, unchanging information, the brain ignores stimuli that are being sensed, but do not change, e(cid:448)e(cid:374)tuall(cid:455) (cid:374)ot (cid:862)heari(cid:374)g(cid:863) the ac.
