The discriminability of remembered magnitudes

Joseph V. Baranski, William M. Petrusic
1992 Memory & Cognition  
Psychometric functions and the associated indices of discriminative performance (i.e., the point of subjective equality [PSEl, just noticeable difference, and Weber fraction) were obtained with the method of constant stimuli using perceptual and remembered line-length standards. Three important results were obtained. First, comparisons with a perceptual or a remembered standard were sensitive to variations of absolute stimulus differences with a common ratio; that is, Weber's law was violated.
more » ... econd, relative to discriminative performance with the longest and shortest remembered standards, comparisons involving mid-range remembered standards displayed increased variability in the PSE and inflated Weber fractions, characteristic of a reduction in the quality of the memorial representation. Finally, large and negative time-order errors (TOE) were observed for successive line judgments but not for those involving remembered standards. The implications of these findings for research concerned with the relationships between perception and memory, as well as the TOE phenomenon, are discussed. Woodworth (1938) , in the first chapter of his classic text, .. Experimental Psychology," concludes: The experimental results are in good agreement on the negative conclusion: No absolute difference exists between an image and a percept, and there is 110 sure criterion by which one can be distinguished from the other. (p. 45)
doi:10.3758/bf03199662 pmid:1508051 fatcat:u5njtkz37rh4bdrjacm5i4ih3e