Quarterly Journal of Experimental Psychology

Two experiments are reported that investigate the response structure and effector transfer of repeated movement sequences. Participants moved a lever to targets sequentially presented on the computer monitor. In Experiment 1 the learning of 10- and 16-element sequences (identical movement pattern) was contrasted. After 1 day of practice the 10-element sequence was organized into fewer subsequences and, thus, performed more rapidly than the 16-element sequence. The imposed organization appeared to be coded in a relatively abstract way, as evidenced by effector transfer that was as good as that on the retention test. In Experiment 2 the 16-element sequence was studied after more extensive practice. By the end of 4 days of practice the participants produced relatively seamless responses void of obvious transitions between subsequences, but the control of the movement was less effector independent than observed earlier in practice. The results suggest that the process of consolidating the sequence, which led to more fluent response production, also resulted in the utilization of effector specific information.

We investigated the impact of anxiety on movement behaviour during the execution of a complex perceptual-motor task. Masters’ (1992) conscious processing hypothesis suggests that under pressure an inward focus of attention occurs, resulting in more conscious control of the movement execution of well-learned skills. The conscious processes interfere with automatic task execution hereby inducing performance decrements. Recent empirical support for the hypothesis has focused on the effects of pressure on end performance. It has not been tested so far whether the changes in performance are also accompanied by changes in movement execution that would be expected following Masters’ hypothesis. In the current study we tested the effects of anxiety on climbing movements on a climbing wall. Two identical traverses at different heights on a climbing wall provided different anxiety conditions. In line with the conscious processing hypothesis we found that anxiety had a significant effect on participants’ movement behaviour evidenced by increases in climbing time and the number of explorative movements (Experiments 1 and 2) and by longer grasping of the holds and slower movements (Experiment 2). These results provide additional support for the conscious processing hypothesis and insight into the relation between anxiety, performance, and movement behaviour.

People are highly skilled at intercepting moving objects and are capable of remarkably accurate timing. The timing accuracy required depends upon the period of time for which contact with a moving target is possible—the “time window” for successful interception. Studies of performance in an experimental interception task that allows this time window to be manipulated suggest that people change aspects of their performance (movement time, MT, and movement speed) in response to changes in the time window. However, this research did not establish whether the observed changes in performance were the results of a response to the time window per se or of independent responses to the quantities defining the time window (the size and speed of a moving target). Experiment 1 was designed to resolve this issue. The speed and size of the target were both varied, resulting in variations in the time window; MT was the primary dependent measure. Predictions of the hypothesis that people respond directly to changes in the time window were verified. Predictions of the alternative hypothesis that responses to changes in target speed and size are independent of one another were not supported. Experiment 2 examined how the type of performance change observed in Experiment 1 was affected by changing the time available for executing the interception. The time available and the target speed were varied, and MT was again the primary dependent measure. MT was smaller when there was less time available, and the effect of target speed (and hence the time window) on MT was also smaller, becoming undetectable at the shortest available time (0.4 s). The results of the two experiments are interpreted as providing information about the “rule” used to preprogramme movement parameters in anticipatory interceptive actions.

Five experiments were carried out to test whether (task-irrelevant) motion information provided by a stimulus changing its position over time would affect manual left–right responses. So far, some studies reported direction-based Simon effects whereas others did not. In Experiment 1a, a reliable direction-based effect occurred, which was not modulated by the response mode—that is, by whether participants responded by pressing one of two keys or more dynamically by moving a stylus in a certain direction. Experiments 1a, 1b, and 2 lend support to the idea that observers use the starting position of target motion as a reference for spatial coding. That is, observers might process object motion as a shift of position relative to the starting position and not as directional information. The dominance of relative position coding could also be shown in Experiment 3, in which relative position was pitted against motion direction by presenting a static and dynamic stimulus at the same time. Additionally, we explored the role of eye movements in stimulus–response compatibility and showed in Experiments 1b and 3a that the execution or preparation of saccadic eye movements—as proposed by an attention-shifting account—is not necessary for a Simon effect to occur.

Children aged 5 and 8 years and adults were tested on a temporal generalization task with a standard duration of 600 ms in a condition with or without corrective feedback. In all conditions, the participants produced orderly temporal generalization gradients, although these were flatter in the younger children, especially in the no-feedback condition. Nevertheless, the results show that the feedback increased the steepness of the generalization gradient in all age groups and in a greater extent in the younger children. Our clock-based model suggested that feedback reduces the variability of the memory representation of the standard duration but also the probability of random responses in the 5-year-olds.

To perform a task that differs from a previously performed one, it is necessary to prepare for the new task as well as to disable the task set of the preceding task. In a series of three experiments we examined whether preparation for a task shift implies a direct update of the task set that is carried over from the preceding trial. To this end, in Experiments 1 and 2 we factorially varied the relation of the task in trial n, first, to the task in trial n − 1 (intertask relation) and, second, to the task that was precued for trial n (precue-to-task relation). Invalid precues resulted in substantial costs, which increased with longer precueing intervals. However, this increasing effect of the precue-to-task relation was not accompanied by a decreasing effect of the intertask relation. Furthermore, both effects had different qualitative properties. These findings suggest that two tasks can be represented concurrently but on two different levels of representation. In Experiment 3 we observed that the persistence of the effect of the intertask relation depends on the possibility that task repetitions can occur in trials in which a task shift is precued. This suggests that the persistence of the effect of the intertask relation is controlled in a context-sensitive way.

Working memory span assesses the maximum number of items that can be remembered in the face of concurrent processing. Models of working memory differ on several dimensions, yet many rely exclusively on this span procedure for their evidence. Three experiments consider an alternative paradigm that attempts to capture the endurance limits for remembering a fixed number of items during concurrent processing. Eight-year-old children performed two versions of this working memory period measure—operation period and reading period. Period scores show healthy test–retest reliability and external validity for scholastic attainment, comparing well with span scores in these respects. In addition, period is highly correlated with span and shows similar effects of varying the order in which stimuli are presented. We conclude that the durability of representations is an important factor in both span and period.