Signal Detection Theory
Psychophysik (1860) Stimulus Perception Neural activity Neurophysiology Inner psychophysics outer psychophysics
Measuring perceptual experience Detection Identification Discrimination scaling
Measuring threshold … Classical ways for perceiving a stimulus Method of adjustment Method of limits Method of constant stimuli
Psychometric function
Classical threshold T = a + (b-a). 50 – pa/(pb-pa)
Objections to classical threshold Smooth transition Subliminal perception Response bias
Signal detection theory Sensory process Vs Decision process
Response bias Liberal response strategy Conservative response strategy Internal criterion
Signal detection paradigm Signal trials Noise trials
Response bias toward ‘Yes’
Response bias toward ‘No’
d’= Z(hit rate) – Z(false alarm rate) d-prime! d’= Z(hit rate) – Z(false alarm rate)
ROC curve