Beaten by Chimpanzees or by the Task? Rethinking Visuospatial Memory Comparisons

Humans often perform worse than chimpanzees in rapid visuospatial memory tasks, which has been interpreted as evidence for lower human working memory (WM) capacity. However, these tasks also impose strong time pressure and require remembering both locations and order, which may make them especially difficult for humans. We tested how presentation mode (sequential vs. simultaneous), encoding time, and memory load affect performance in a visuospatial WM task previously tested with chimpanzees. Two hundred ninety participants completed adaptive tasks in which digits were presented either one at a time with increasing load or all at once with decreasing display duration. Using beta-binomial mixed-effects models and survival analysis, we found that longer encoding time improved accuracy, but this benefit depended on presentation mode. Sequential presentation supported performance across increasing difficulty, whereas simultaneous presentation led to rapid task failure. Performance declined sharply beyond about five to six items. These results suggest that poorer human performance in these tasks reflects task structure and time pressure rather than fundamentally lower visuospatial WM capacity.