Memory enhancing effects: Does a production effect exist in short-term memory tasks and if so, how does it interfere with the bootstrapping effect?

Abstract

Working memory performance during a serial digit recall task has been found to benefit from task-irrelevant additional visuospatial information in the stimulus layout, which is called the bootstrapping paradigm (Darling and Havelka, 2010). The underlying encoding process has been speculated to be motoric in nature (Reisberg, Rappaport and O'Shaughnessy, 1984), and LTM-research showing the reliable and effortless benefits of vocally producing a to-be-remembered-item (MacLeod et al., 2010) led to the hypothesis that information that can boost working memory performance can be actively produced by participants concurrently during a verbal serial digit recall task and have similar encoding processes to those of the bootstrapping paradigm. In this study 32 participants had to recall seven digits in the correct order while either (1) doing nothing, (2) producing the digits verbally, (3) producing them manually by typing them into a keypad, or (4) combining the latter two tasks. The analysis showed no facilitating effect of the production-conditions. On the contrary, performance in the motor-condition was significantly worse than in all other conditions. This specific disruptive effect could represent an attentional focus on motor-production, and subsequent cognitive task interference between motor-control processes and mental pattern imagery, according to Cowan's embedded process model (1999). However, further research is needed to replicate and explore this finding.