Larger between-task crosstalk in children than in adults: Behavioral results from the backward crosstalk paradigm and a diffusion model analysis

•Backward crosstalk indicates Task 2 influences already on Task 1 performance.•Backward crosstalk is larger in 5-6 year old children than in young adults.•Diffusion modeling suggests different reasons for backward crosstalk in children.•Children and adults show very flexible adjustments of behavior following conflict.

In dual-task settings, one can find influences from Task 2 processing even on Task 1 performance, an effect referred to as the backward crosstalk effect (BCE). The size of the BCE has been taken as an index of how well Task 1 processing can be shielded against concurrently ongoing Task 2 processes. In the current study, we compared the size of the BCE between adults and a group of 5- and 6-year-old children. First, the BCE turned out to be larger in children than in adults. Second, both groups exhibited a comparable adjustment of behavior in response to just experienced conflict; in both groups, the BCE was smaller following conflict trials than following no-conflict trials. Third, a diffusion model analysis suggests that the source for the BCE is different in adults than in children. In particular, not parallel Task 2 response activation appears to be the source of the BCE in children. Rather, non-decisional processes appear to be responsible for the BCE in this age group. Thus, this study shows that (a) 5- and 6-year-old children can perform dual-tasks, but (b) they show slightly larger signs of between-task crosstalk, and (c) the exact reasons for this appear to be different from those responsible in adults.