Working memory performance and preoccupying thoughts in female dieters: Evidence for a selective central executive impairment

Objective. The study aimed to extend previous research into the impaired cognitive performance of spontaneous dieters by employing the Double Span Memory Task to investigate the relationship between weight-loss dieting and performance simultaneously on the three subsystems of working memory. Method. A sample of 33 dieting and 33 non-dieting women were presented with increasingly longer sequences of common objects, displayed successively in different, randomly chosen locations of a 4 X 4 grid. Participants were then asked to name the objects (phonological loop), point to the locations (visuospatial sketch pad), or both (central executive). Participants also completed self-report measures of preoccupying cognitions, dietary restraint, depressed affect, and verbal intelligence. Results. Current dieters performed more poorly than non-dieters on combined recall, but not on the single recall of objects or locations. They also scored more highly on self-rated preoccupying cognitions. Conclusion. Dieting to lose weight selectively impairs central executive functioning, rather than the storage capacity of the two slave systems. This dieting-related central executive deficit is at best partly attributable to the preoccupying thoughts about food, weight, and body shape accompanying dieting.