| The effect of mixing stimulus durations on time judgments was examined in two experiments. All temporal judgments were obtained under dual-task conditions. In both experiments, stimulus duration and the context in which sample intervals were presented were manipulated in a mixed factorial design. In Experiment 1, two sample durations (12 and 24 s) were presented, while in Experiment 2 the number of sample durations was increased to three durations (6, 12, and 24 s). Sample durations were presented under both single and mixed duration conditions. Under the single duration condition, one sample interval was presented throughout an experimental session. Under the mixed duration condition, all the sample durations were presented in each experimental session. In both experiments, temporal judgments were shorter and standard deviations were smaller at the longest sample duration under the mixed duration condition when compared to the single duration condition. Relative measures of variability, coefficients of variation, did not differ between the two conditions. Moreover, flatter functions relating log temporal judgments to log sample duration were obtained under the mixed duration condition, although differences were significant only in Experiment 2. The flatter functions resulted from both a lower slope and higher intercept value under the mixed duration condition. These findings are discussed with respect to attentional clock models of timing. |
