PS262 Lecture Notes - Lecture 2: Gustav Fechner, Psychometric Function, Absolute Threshold
Document Summary
Introduction: big picture: (cid:449)e (cid:272)an"t study per(cid:272)eption if (cid:449)e (cid:272)an"t e(cid:448)en say (cid:449)hether an o(cid:271)ser(cid:448)er perceives a stimulus or not, psychophysics: determining quantitative relationships between. Perception [internal psychological: gustav fechner october 22, 1850: discovered the quantitative relationship between mind (mental sensation) & body (material/physical stimulus) Psychometric function: experimenter presents different stimulus intensities, task = detection (did you see a light, or not?) Smallest amnt of stimulus energy necessary for observer to detect a stimulus: method of limits, method of constant stimuli: random ordering of stimulus intensities, method of adjustment. Average 80 and 90 to get threshold of 85. Threshold is 95. (average two crossovers (85 and 95) to get 90) Difference threshold: smallest diff. between 2 stimuli a person can detect, just-noticeable difference, jnd. Appendix: response criterion, criterion = amnt of se(cid:374)so(cid:396)y i(cid:374)fo o(cid:271)se(cid:396)(cid:448)e(cid:396) (cid:396)e(cid:395)ui(cid:396)es fo(cid:396) sayi(cid:374)g (cid:862)yes(cid:863) Low criterion: (cid:862)yes(cid:863) e(cid:448)e(cid:374) if do(cid:374)"t pe(cid:396)(cid:272)ei(cid:448)e (cid:373)u(cid:272)h e(cid:448)ide(cid:374)(cid:272)e fo(cid:396) to(cid:374)e.
