Dual Task Performance in Children and Adults with Autism

Background: Many of us have experienced the negative effects of divided attention (e.g., conversing while driving) due to “resource limitations” on attention and response selection (e.g., Watter & Logan, 2006). Negative effects may depend on functional connections between the relevant “dual” tasks, as performance of tasks that are more functionally and anatomically similar will be relatively more impacted by multitasking. Individuals with ASD might exhibit less impairment in multitasking, due to hypothesized decreases in functional connectivity. Alternatively, if multi-tasking critically depends on effective executive functioning, ASD may be characterized by poor multitasking. In addition to these theoretical implications, multi-tasking performance is highly relevant for everyday functioning.

Objectives: To explore functional connectivity through a behavioral dual-task paradigm.

Methods: 19 Participants with ASD and 42 typically developing controls ages 11-54, matched on PPVT, completed a well-studied dual-task paradigm, in which they were asked to tap with their right or left index fingers while simultaneously describing a visually-presented image. Tapping rate was also recorded in a baseline “single-task” condition.

Results: All participants tapped at equivalent rates in the baseline condition (p’s > .3), and rates decreased in the dual-task condition for both groups. However, the ASD group was significantly more slowed when multitasking (2.9 fewer taps in TD group, 4.8 in ASD group, p = .008). There was a group by handedness interaction, with left-handed ASD participants (n = 5) showing a significantly greater decrease than left-handed controls (n = 15).

Conclusions: Findings indicate that all individuals with ASD, and especially left-handed individuals, experienced more, rather than less, interference when multi-tasking. This suggests two possibilities: ASD may not be characterized by a lack of functional connectivity; alternatively, dual task performance reflects higher-order executive processes, in addition to interference between closely-related anatomical regions, in ASD.