The Diverse Central Executive during everyday Multi-Tasking

Multi-tasking defined by interleaving numerous tasks in order to achieve many goals in a short amount of time is essential in everyday life and intuitively involves the central executive component of working memory. The link between executive processing and everyday functioning has not been consistently observed in clinical studies with traditional executive tests but has been demonstrated in studies using ecologically valid tests. This may be due to the diverse nature of the central executive. Numerous separable executive processes have been established such as ‘shifting’ and ‘inhibition’ and recent evidence suggests that dual task ability is a further separable executive process which may be particularly important in everyday functioning. However this link has never been formally investigated in the healthy population. An ecologically valid test of multi-tasking, the Edinburgh Virtual Errands Test (E-VET) (Logie, Trawley and Law, 2010) and a traditional test of executive processing the Wisconsin Card Sorting Test (WCST) were given to a group of healthy young participants (n=85) along with three domain specific tests of executive functioning, a dual task test and intelligence tests. It was predicted that the results would support the multi-component model of executive processing which includes dual tasking as a separable executive function and that the executive tests would be predictive of the ecologically valid test (E-VET) performance and the traditional executive test performance (WCST). An exploratory factor analysis was used to split E-VET performance into two components - memory and intentionality. A significant proportion of the variance in the intentionality component of multi-tasking was predicted by dual tasking and general intelligence ‘g’. Only general intelligence significantly predicted WCST performance and latent memory within multi-tasking. Correlation analysis gave support to the multi-component model of executive processing and dual task ability appeared to be separable to measures of ‘shifting’ and ‘inhibition’ however more stringent statistical techniques are recommended. These results strengthen the argument for using more complex, ecologically valid paradigms when studying the diverse central executive and multi-tasking