Memory for positional movements as a component of the visuospatial working memory

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

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.

Model expertise does not influence automatic imitation

Social learning theories state that new skills can be learned by observing others. Automatic imitation is thought to play an important role in this process. However, whether imitation is beneficial to learning critically depends on the expertise of the imitated person. Therefore, the aim of this study was to investigate the influence of model expertise on automatic imitation, by comparing automatic imitation of an expert and non-expert model in two within-subject experiments. In a first experiment (N = 61), we manipulated the perception of expertise in one task and tested how this influenced automatic imitation in a separate task. However, in contrast to our hypothesis, and in spite of a successful manipulation check, we did not find evidence for an effect of model expertise on imitative behavior. To exclude the alternative explanation that this was due to a lack of transfer of expertise attribution, we then conducted a second, preregistered experiment (N = 125), in which we manipulated model expertise using the same task also used to measure automatic imitation. However, in line with the results of Experiment 1, we found no evidence for an effect of model expertise on imitative behavior. These results put important constraints on the role of automatic imitation in motor learning.