Author's personal copy Moving and memorizing: Motor planning modulates the recency effect in serial and free recall Matthias Weigelt a,b, * , David A. Rosenbaum c , Sven Huelshorst a , Thomas Schack a,b a Faculty of Psychology and Sport Sciences, University of Bielefeld, PF 100 131, 33501 Bielefeld, Germany b Center of Excellence ‘‘Cognitive Interaction Technology” (CITEC), University of Bielefeld, Bielefeld, Germany c Department of Psychology, Pennsylvania State University, USA article info Article history: Received 19 February 2008 Received in revised form 15 June 2009 Accepted 17 June 2009 Available online 9 July 2009 PsycINFO classification: 2330 2340 2343 Keywords: Motor planning Grip selection End-state comfort effect Short-term memory Serial position curve abstract Motor planning has generally been studied in situations where participants carry out physical actions without a particular purpose. Yet in everyday life physical actions are usually carried out for higher-order goals. We asked whether two previously discovered motor planning phenomena – the end-state comfort effect and motor hysteresis – would hold up if the actions were carried out in the service of higher-order goals. The higher-order goal we chose to study was memorization. By focusing on memorization, we asked not only how and whether motor planning is affected by the need to memorize, but also how mem- ory performance might depend on the cognitive demands of motor planning. We asked university-stu- dent participants to retrieve cups from a column of drawers and memorize as many letters as possible from the inside of the cups. The drawers were opened either in a random order (Experiment 1) or in a regular order (Experiments 2 and 3). The end-state comfort effect and motor hysteresis were replicated in these conditions, indicating that the effects hold up when physical actions are carried out for the sake of a higher-order goal. Surprisingly, one of the most reliable effects in memory research was eliminated, namely, the tendency of recent items to be recalled better than earlier items – the recency effect. This outcome was not an artifact of memory being uniformly poor, because the tendency of initial items to be recalled better than later items – the primacy effect – was obtained. Elimination of the recency effect was not due to the requirement that participants recall items in their correct order, for the recency effect was also eliminated when the items could be recalled in any order (Experiment 3). These and other aspects of the results support recent claims for tighter links between perceptual-motor control and intel- lectual (symbolic) processing than have been assumed in the past. Ó 2009 Elsevier B.V. All rights reserved. 1. Introduction Previous research has shown that the way people reach for ob- jects depends on what they plan to do with the objects. Such antic- ipatory effects were first observed by Marteniuk, MacKenzie, Jeannerod, Athenes, and Dugas (1987), who studied the speed of the hand as it either approached an object to be tossed into a bin or another object to be screwed into a socket. Marteniuk et al. found that the speed of the hand as it approached the objects dif- fered in the two conditions. The hand moved more quickly when it approached the object to be tossed than when it approached the objects to be fitted into a socket. Weir, MacDonald, Mallat, Leavitt, and Roy (1998) extended this finding by showing that the timing of reach-to-grasp movements depended on whether participants intended to place a disk in a well, place the disk in a box, or toss the disk into a box. Under all three tasks, the object manipulated (i.e., the disk) was the same, as was its starting location. Weir et al.’s finding that hand kinemat- ics changed as a function of planning (even with the same object to be grasped) helped establish that participants’ mental states were responsible for the observed kinematic changes. Another demonstration of mental states affecting forthcoming activity came from Epelboim et al. (1997), who found that the way the eyes scan an array of targets differed depending on whether the observer was merely looking at the targets or was pre- paring to tap the targets with the finger. In this study, the targets being visually scanned were identical in the two conditions, so the change in eye movements could only be ascribed to the partic- ipants’ motor planning per se. Anticipatory effects have also been observed for hand orienta- tion, which is the main motor-related variable to be studied in this report. Haggard (1998) found that participants changed the orien- tation of the hand on an octagonal object depending on how they planned to move the object to each of a number of target positions defined with respect to orientation as well as horizontal location. 0001-6918/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.actpsy.2009.06.005 * Corresponding author. Tel.: +49 521 1062420; fax: +49 521 1066432. E-mail address: matthias.weigelt@uni-bielefeld.de (M. Weigelt). Acta Psychologica 132 (2009) 68–79 Contents lists available at ScienceDirect Acta Psychologica journal homepage: www.elsevier.com/locate/actpsy