PSYC100 Lecture Notes - Lecture 5: Detection Theory, Absolute Threshold, Response Bias

• School: University of Delaware
• Department: Psychology
• Course: PSYC100
• Professor: Quinn Paul

Document Summary

Psychophysics: relationship b/w physical energy & psychological experience: detection, discrimination, growth of perception. Correct rejection: variations that affect response criterion: change % of hits and false alarms. Ex) manipulation: change % of trials on which stimulus is present. 90% of trials stimulus present: low response criterion (threshold for saying yes is low) - sa(cid:455) (cid:862)(cid:455)es(cid:863) (cid:449)ithout (cid:373)u(cid:272)h support or pro(cid:448)o(cid:272)atio(cid:374: hits increase, false alarms increase. 10% of trials stimulus present: high response criterion (threshold for yes is high) say (cid:862)(cid:455)es(cid:863) (cid:449)ith lots of e(cid:448)ide(cid:374)(cid:272)e: hits decrease, false alarms decrease. Real-life application of detection: radiologist: detect odd spot evidence of cancer, penalty for fa: additional tests (inconvenience, penalty for miss: not catching the odd spot (death) Low (lax) response criterion = many hits, few misses, some fas: radar operator missile defense, penalty for fa: war, penalty for miss: lose a few seconds in sounding alarm. High (strict) response criterion = less hits, less false alarms.