Visuospatial bootstrapping: Binding useful visuospatial information during verbal working memory encoding does not require set-shifting executive resources

Abstract

Immediate serial recall of digits is better when the digits are shown by highlighting them in a familiar array, such as a phone keypad, compared to presenting them serially in a single location; a pattern referred to as 'visuospatial bootstrapping'. This pattern implies the establishment of temporary links between verbal and spatial working memory, alongside access to information in long term memory. However, the role of working memory control processes like those implied by the 'Central Executive' in bootstrapping has not been directly investigated. Here we report a study addressing this issue, focusing on executive processes of attentional shifting. Tasks in which information has to be sequenced are thought to be heavily dependent on shifting. Memory for digits presented in keypads versus single locations was assessed under two secondary task load conditions, one with and one without a sequencing requirement, and hence differing in the degree to which they invoke shifting. Results provided clear evidence that multimodal binding (visuospatial bootstrapping) can operate independently of this form of executive control process.