Locus of the redundant-signals effect in bimodal divided attention: A neurophysiological analysis

We reanalyzed the data from the study of Lamarre, Busby, and Spidalieri (1983). In that study, the activity of single neurons in area 4 of the motor cortex was recorded during a bimodal detection task in which a monkey (Macaca mulatta)had to respond as quickly as possible to a visual or an auditory signal or to both (redundant trials). Manual responses on redundant trials were speeded by the presence of both signals, as is typically found. The times between signal onsets and the first changes in neuronal activity were also speeded by redundant signals, but there was no difference between redundant-signals and single-signal trials in the time between the change in neuronal activity and movement onset. These results suggest that late motor processes are not speeded by redundant signals in bimodal detection tasks.     

Emotions and false memories: valence or arousal?

The effects of mood on false memories have not been studied systematically until recently. Some results seem to indicate that negative mood may reduce false recall and thus suggest an influence of emotional valence on false memory. The present research tested the effects of both valence and arousal on recall and recognition and indicates that the effect is actually due to arousal. In fact, whether participants' mood is positive, negative, or neutral, false memories are significantly more frequent under conditions of high arousal than under conditions of low arousal.     

Surface‐ and deep‐level dissimilarity effects on social integration and individual effectiveness related outcomes in work groups: A meta‐analytic integration

Prior research linking demographic (e.g., age, ethnicity/race, gender, and tenure) and underlying psychological (e.g., personality, attitudes, and values) dissimilarity variables to individual group member's work‐related outcomes produced mixed and contradictory results. To account for these findings, this study develops a contingency framework and tests it using meta‐analytic and structural equation modelling techniques. In line with this framework, results showed different effects of surface‐level (i.e., demographic) dissimilarity and deep‐level (i.e., underlying psychological) dissimilarity on social integration, and ultimately on individual effectiveness related outcomes (i.e., turnover, task, and contextual performance). Specifically, surface‐level dissimilarity had a negative effect on social integration under low but not under high team interdependence. In return, social integration fully mediated the negative relationship between surface‐level dissimilarity and individual effectiveness related outcomes under low interdependence. In contrast, deep‐level dissimilarity had a negative effect on social integration, which was stronger under high and weaker under low team interdependence. Contrary to our predictions, social integration did not mediate the negative relationship between deep‐level dissimilarity and individual effectiveness related outcomes but suppressed positive direct effects of deep‐level dissimilarity on individual effectiveness related outcomes. Possible explanations for these counterintuitive findings are discussed.     

Mindfulness meditation counteracts self-control depletion

Mindfulness meditation describes a set of different mental techniques to train attention and awareness. Trait mindfulness and extended mindfulness interventions can benefit self-control. The present study investigated the short-term consequences of mindfulness meditation under conditions of limited self-control resources. Specifically, we hypothesized that a brief period of mindfulness meditation would counteract the deleterious effect that the exertion of self-control has on subsequent self-control performance. Participants who had been depleted of self-control resources by an emotion suppression task showed decrements in self-control performance as compared to participants who had not suppressed emotions. However, participants who had meditated after emotion suppression performed equally well on the subsequent self-control task as participants who had not exerted self-control previously. This finding suggests that a brief period of mindfulness meditation may serve as a quick and efficient strategy to foster self-control under conditions of low resources.     

On the Nature of the Probe Reaction-Time Task to Uncover the Attentional Demands of Movement

McLeod (1980) reported some findings which showed that no phase of a movement was more attention-demanding than the other phases, contrary to all the results previously reported (e.g., Ells, 1973; Glencross, 1980). However, McLeod used a paradigm in which the two tasks were serial. Each task consisted of a series of 50 reaction time (RT) trials and/or 50 aiming movement trials. In addition to this, the interval of time between a response and the following signal within each series was constant. In order to try to replicate McLeod’s findings, two experiments were conducted in which the response-signal interval was manipulated. The hypothesis was that time certainty associated with a constant interval would facilitate the allocation of time and would thus artificially reduce the interference between tasks. In Experiment I, manual responses were used for the RT task; in Experiment II, they were vocal. Manipulation of the response-signal interval does not change one of the conclusions reached by McLeod: when the RT task involves vocal responses and the results on the RT task are analyzed in terms of response rather than stimulus arrival during the movement, then there is no phase of the movement which is more attention-demanding than the other phases. However, the results of Experiment II in which both the vocal RT task and the movement task significantly deteriorated in the dual-task condition were taken as an indication that the movement studied involved central attentional demands.     

Impaired word naming in right-brain-damaged right-handers: error types and time-course analyses

The purpose of this study is to search for cues that could account for the fact that right-hemisphere lesions affect word naming when the criterion for naming is semantic. The authors analyzed the errors as well as the time course of productions of 35 vascular right-brain-damaged subjects (RBD) and 20 control subjects (C) in a semantic-based word-naming task. Results show that there are no differences between groups in terms of (a) the number of errors produced and, (b) the patterns of error types. However, results also show a reduction of verbal fluency for semantic criteria in RBD-subjects present only after the first 30 seconds of production. These results indicate that reduction of word production in RBD-subjects is not the consequence of nonspecific factors such as perseveration or spontaneity, but reflects problems with the less automatized processes permitting exploration of semantic organization, either because scanning process are affected, or because the presence of a discreet semantic impairment prevents scanning from being as efficient. Given that efficient exploration of semantic knowledge is important for lexico-semantic functioning, the present results suggest that the right hemisphere contributes to some aspects of lexico-semantic processing necessary for language production.     

SIMSTAT: Bootstrap computer simulation and statistical program for IBM personal computers

SIMSTAT is a computer program that provides bootstrap confidence intervals and estimates distribution parameters for 27 univariate and bivariate statistics. Because it permits variation of the bootstrap sample size, it is a convenient tool for research planning, allowing comparison of power estimates and estimator precision for various estimators and/or sample sizes. SIMSTAT also is a useful tool for studying the robustness of various statistics on real-world data and may be helpful in teaching statistical principles.