# Inter-individual variability (but intra-individual stability) of overt versus covert rehearsal strategies in a digital Corsi task

## TL;DR

This study explores how people use overt and covert attention strategies in a digital Corsi task, finding that individuals consistently prefer one strategy while showing variability across participants.

## Contribution

A novel digital Corsi task is introduced to quantify and classify individual differences in overt and covert rehearsal strategies.

## Key findings

- Participants show consistent strategy preference across all task conditions and sequence lengths.
- There is significant inter-individual variability in the use of overt and covert rehearsal strategies.
- Behavioral metrics like Corsi span and pupil size reflect differences in strategy use.

## Abstract

The Corsi (block-tapping) paradigm is a classic and well-established visuospatial working memory task in humans involving internal computations (memorizing of item sequences, organizing and updating the memorandum, and recall processes), as well as both overt and covert shifts of attention to facilitate rehearsal, serving to maintain the Corsi sequences during the retention phase. Here, we introduce a novel digital version of a Corsi task in which i) the difficulty of the memorandum (using sequence lengths ranging from 3 to 8) was controlled, ii) the execution of overt and/or covert attention as well as the visuospatial working memory load during the retention phase was manipulated, and iii) shifts of attention were quantified in all experimental phases. With this, we present behavioral data that demonstrate, characterize, and classify the individual effects of overt and covert strategies used as a means of encoding and rehearsal. In a full within-subject design, we tested 28 participants who had to solve three different Corsi conditions. While in condition A neither of the two strategies were restricted, in condition B the overt and in condition C the overt as well as the covert strategies were suppressed. Analyzing Corsi span, (eye) exploration index, and pupil size (change), data clearly show a continuum between overt and covert strategies over all participants (indicating inter-individual variability). Further, all participants showed stable strategy choice (indicating intra-individual stability), meaning that the preferred strategy was maintained in all three conditions, phases, and sequence lengths of the experiment.