A meta-analysis of 117 experiments evaluated the effects of cognitive load on duration judgments. Cognitive load refers to information-processing (attentional or working-memory) demands. Six types of cognitive load were analyzed to resolve ongoing controversies and to test current duration judgment theories. Duration judgments depend on whether or not participants are informed in advance that they are needed: prospective paradigm (informed) versus retrospective paradigm (not informed). With higher cognitive load, the prospective duration judgment ratio (subjective duration to objective duration) decreases but the retrospective ratio increases. Thus, the duration judgment ratio differs depending on the paradigm and the specific type of cognitive load. As assessed by the coefficient of variation, relative variability of prospective, but not retrospective, judgments increases with cognitive load. The prospective findings support models emphasizing attentional resources, especially executive control. The retrospective findings support models emphasizing memory changes. Alternative theories do not fit with the meta-analytic findings and are rejected.
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