Bimanual or unimanual stacking strategies under different cognitive load: Evidence of a cognitive/action trade-off in the coordination strategy of 3- to 5-year-olds

Previous studies have found that increased cognitive load during a task might result in the use of ‘easier’ motor strategies that nevertheless achieve task goals. Here, we investigated the influence of cognitive load on bimanual or unimanual strategy use in preschoolers, through a combination of secondary data analysis and new empirical data. Experiment 1 investigated block-stacking strategies under high, medium and low cognitive load tasks in 3-year-olds and showed that 3-year-olds demonstrated significantly more unimanual strategy use in the high cognitive load task. Experiment 2 investigated (i) whether this effect persisted across preschool years, and (ii) whether it was modulated by differences in executive function abilities. There was no age effect in motor strategy use under high cognitive load from 3 to 5 years of age. However, individual differences in inhibitory control and working memory use were significantly associated with differences in unimanual strategy use. These results are interpreted as evidence for a cognitive/action trade-off in which higher cognitive demands result in the adjustment of motor strategies such as use of unimanual stacking instead of bimanual coordination in preschoolers.