Cognitive Aspects of Difference Testing: Memory and Interstimulus Delay

There are many ways in which a laboratory difference test differs from ‘real life’ discrimination of foods. One of these is the interval of time between tasting the two stimuli to be discriminated. To investigate this, judges performed same‐different discrimination tests using a citrus flavored beverage as a medium. The time interval between tasting the standard and comparison stimuli was varied. In this initial study, short intervals of zero, 30, 60 s were examined. For judges unfamiltar with the stimuli, performance deteriorated as the time interval increased. For judges familiar with the stimuli, the zero time interval elicited best performance but there was no decrease in performance when the interval was increased from 30 to 60 s. The results were explained by hypothesizing different types of memory trace for the standard stimulus being utilized for comparison with the comparison stimulus.