PSYC 2390 Lecture Notes - Lecture 2: Response Bias, Psychophysics, Presbyterian Polity

• School: University of Guelph
• Department: Psychology
• Course: PSYC 2390
• Professor: Lana Trick

Document Summary

Discrimination threshold (difference threshold or jnd just noticeable difference) Smallest difference in intensity that you can perceive. Colour threshold has to do with wavelength. How to measure jnd: method of limits. Requires a standard (always stays the same) Requires a comparison (something that changes: method of adjustment, method of constants. * only ay heavier or lighter cannot ay equal. ** standard is felt first, then comparison negative time error, something in the past seem fainter than the present (underestimate events from the past) *** subjective equal (lighter half the time, heavier half the time) not actually equal: example: 100mg vs 99 mg @ 50% **** jnd = [intensity more intense (75% of time) intensity more intense (25% of time)]/2. Cant notice the difference at one point, but can in other. K = 2/100 (2 is from jnd, 100 from standard solved above) Either the absolute or difference threshold require classis psychophysics.