Fig. 1.

Trial events during the interval categorization task and behavioral results. a Monkeys categorized the interval between the first and second stimulus presentation as “short” or “long” by moving the red cursor into the orange or blue circular targets, respectively. b An example of a possible target configuration, with the response circles 180° apart. Gray circles (not visible in the actual task) show the eight possible target locations. c The three blocks of stimuli employed in this study (T1, T2, and T3). The short/long implicit limits for T1, T2, and T3 are 350, 685, and 1195 ms, respectively. Note that some time durations could be correctly categorized either as “short” or as “long” depending on the particular block presented to the monkey. d Psychometric curves for the two monkeys for the three blocks of durations. Dots represent the mean (±SEM) probability of categorizing a particular interval as long. e Mean (±SEM) of the reaction times of the monkey 1 as a function of the test intervals for the three blocks of stimuli