Non-dominant Task Research Articles

The role of brain-localized gamma and alpha oscillations in inattentional deafness: implications for understanding human attention.

The processes involved in how the attention system selectively focuses on perceptual and motor aspects related to a specific task, while suppressing features of other tasks and/or objects in the environment, are of considerable interest for cognitive neuroscience. The goal of this experiment was to investigate neural processes involved in selective attention and performance under multi-task situations. Several studies have suggested that attention-related gamma-band activity facilitates processing in task-specific modalities, while alpha-band activity inhibits processing in non-task-related modalities. However, investigations into the phenomenon of inattentional deafness/blindness (inability to observe stimuli in non-dominant task when primary task is demanding) have yet to observe gamma-band activity. This EEG experiment utilizes an engaging whole-body perceptual motor task while carrying out a secondary auditory detection task to investigate neural correlates of inattentional deafness in natural immersive high workload conditions. Differences between hits and misses on the auditory detection task in the gamma (30-50 Hz) and alpha frequency (8-12 Hz) range were carried out at the cortical source level using LORETA. Participant auditory task performance correlated with an increase in gamma-band activity for hits over misses pre- and post-stimulus in left auditory processing regions. Alpha-band activity was greater for misses relative to hits in right auditory processing regions pre- and post-stimulus onset. These results are consistent with the facilitatory/inhibitory role of gamma/alpha-band activity for neural processing. Additional gamma- and alpha-band activity was found in frontal and parietal brain regions which are thought to reflect various attentional monitoring, selection, and switching processes. The results of this study help to elucidate the role of gamma and alpha frequency bands in frontal and modality-specific regions involved with selective attention in multi-task immersive situations.

The observant android: Limited social facilitation and inhibition from a copresent social robot.

Human–robot collaborations that operate in shared spaces are anticipated to become increasingly common in coming years. Decades of social psychological research have revealed that human observers positively influence people’s performance in dominant and negatively in nondominant tasks. While studies indicate moderate support for social facilitation/inhibition effects with robot observers, this evidence is hotly debated. Addressing known methodological criticism, this study investigates how a copresent robot-observer affects Stroop task performance and whether perceptions of that robot’s mental capacities have explanatory value. Results reveal limitations in transferring social facilitation/inhibition theory to robots. Since participants reported high task attention levels across conditions, emerging flow states may have helped them circumvent social facilitation/inhibition mechanisms. It may thus be recommended for future research to consider flow dynamics when investigating social performance effects.

Supplemental Material for The observant android: Limited social facilitation and inhibition from a copresent social robot.

Human–robot collaborations that operate in shared spaces are anticipated to become increasingly common in coming years. Decades of social psychological research have revealed that human observers positively influence people’s performance in dominant and negatively in nondominant tasks. While studies indicate moderate support for social facilitation/inhibition effects with robot observers, this evidence is hotly debated. Addressing known methodological criticism, this study investigates how a copresent robot-observer affects Stroop task performance and whether perceptions of that robot’s mental capacities have explanatory value. Results reveal limitations in transferring social facilitation/inhibition theory to robots. Since participants reported high task attention levels across conditions, emerging flow states may have helped them circumvent social facilitation/inhibition mechanisms. It may thus be recommended for future research to consider flow dynamics when investigating social performance effects.

Interlimb differences in coordination of unsupported reaching movements

Previous research suggests that interlimb differences in coordination associated with handedness might result from specialized control mechanisms that are subserved by different cerebral hemispheres. Based largely on the results of horizontal plane reaching studies, we have proposed that the hemisphere contralateral to the dominant arm is specialized for predictive control of limb dynamics, while the non-dominant hemisphere is specialized for controlling limb impedance. The current study explores interlimb differences in control of 3-D unsupported reaching movements. While the task was presented in the horizontal plane, participant’s arms were unsupported and free to move within a range of the vertical axis, which was redundant to the task plane. Results indicated significant dominant arm advantages for both initial direction accuracy and final position accuracy. The dominant arm showed greater excursion along a redundant axis that was perpendicular to the task, and parallel to gravitational forces. In contrast, the non-dominant arm better impeded motion out of the task-plane. Nevertheless, non-dominant arm task errors varied substantially more with shoulder rotation excursion than did dominant arm task errors. These findings suggest that the dominant arm controller was able to take advantage of the redundant degrees of freedom of the task, while non-dominant task errors appeared enslaved to motion along the redundant axis. These findings are consistent with a dominant controller that is specialized for intersegmental coordination, and a non-dominant controller that is specialized for impedance control. However, the findings are inconsistent with previously documented conclusions from planar tasks, in which non-dominant control leads to greater final position accuracy.

Long-term memory and the control of attentional control

Task-switch costs and in particular the switch-cost asymmetry (i.e., the larger costs of switching to a dominant than a non-dominant task) are usually explained in terms of trial-to-trial carry-over of task-specific control settings. Here we argue that task switches are just one example of situations that trigger a transition from working-memory maintenance to updating, thereby opening working memory to interference from long-term memory. We used a new paradigm that requires selecting a spatial location either on the basis of a central cue (i.e., endogenous control of attention) or a peripheral, sudden onset (i.e., exogenous control of attention). We found a strong cost asymmetry that occurred even after short interruptions of otherwise single-task blocks (Exp. 1–3), but that was much stronger when participants had experienced the competing task under conditions of conflict (Exp. 1–2). Experiment 3 showed that the asymmetric costs were due to interruptions per se, rather than to associative interference tied to specific interruption activities. Experiment 4 generalized the basic pattern across interruptions varying in length or control demands and Experiment 5 across primary tasks with response-selection conflict rather than attentional conflict. Combined, the results support a model in which costs of selecting control settings arise when (a) potentially interfering memory traces have been encoded in long-term memory and (b) working-memory is forced from a maintenance mode into an updating mode (e.g., through task interruptions), thereby allowing unwanted retrieval of the encoded memory traces.

An electrophysiological correlate of conflict processing in an auditory spatial Stroop task: The effect of individual differences in navigational style

Recent work has identified an event-related potential (ERP) component, the incongruency negativity (Ninc), which is sensitive to auditory Stroop conflict processing. Here, we investigated how this index of conflict processing is influenced by individual differences in cognitive style. There is evidence that individuals differ in the strategy they use to navigate through the environment; some use a predominantly verbal-egocentric strategy while others rely more heavily on a spatial-allocentric strategy. In addition, navigational strategy, assessed by a way-finding questionnaire, is predictive of performance on an auditory spatial Stroop task, in which either the semantic or spatial dimension of stimuli must be ignored. To explore the influence of individual differences in navigational style on conflict processing, participants took part in an auditory spatial Stroop task while the electroencephalogram (EEG) was recorded. Whereas behavioral performance only showed a main effect of congruency, we observed the predicted three-way interaction between congruency, task type and navigational style with respect to our physiological measure of Stroop conflict. Specifically, congruency-dependent modulation of the Ninc was observed only when participants performed their non-dominant task (e.g., verbal navigators attempting to ignore semantic information). These results confirm that the Ninc reliably indexes auditory Stroop conflict and extend previous results by demonstrating that the Ninc is predictably modulated by individual differences in cognitive style.

The effects of attentional load on saccadic task switching

Everyday life requires the ability to flexibly switch between tasks. Often, task switching is accompanied by concurrent cognitive activities that compete for limited attentional resources. This study aimed to characterize the effects of attentional load on task switching. In experiment 1, participants performed an interleaved pro-saccade and anti-saccade task. In experiment 2, participants performed an interleaved pro-saccade and anti-saccade task simultaneously with a rapid serial visual presentation task that has been shown to create an attentional load. Error rates and reaction times of pro-saccades and anti-saccades were analysed for both experiments separately and together. Overall, error rates and reaction times increased with attentional load. With attentional load, switches to pro-saccades were associated with increased error rates and reaction times, whereas switches to anti-saccades were only associated with increased error rates. We propose that attentional load interferes with neural task-set representation and that the resulting executive control is different for the dominant and non-dominant task.

切り替えコストの非対称性―片側性準備電位による検討―

Switching to a dominant task incurs larger costs than switching to a non-dominant task. This study investigated whether this cost asymmetry derives from the inhibition of the dominant task rule that occurred during the previous trial. Participants were presented with a five-letter array consisting of (left) and (right), and asked to respond to the central target letter after being informed about the task rule with a pre-cue. The rule was switched between dominant (left-hand to, right-hand to) and non-dominant tasks (right-hand to, left-hand to) every two trials. Reaction times revealed the asymmetrical switch cost and the effect of target-flanker congruency. Stimulus-locked lateralized readiness potentials showed that the dominant task rule was inhibited during the non-dominant task, whereas this inhibition was not carried over to the dominant task trial.

Task selection cost asymmetry without task switching

The switch cost asymmetry (i.e., larger costs when switching from a nondominant into a dominant task than vice versa) has been explained in terms of the trial-to-trial carryover of activation levels required for the dominant versus the nondominant task. However, there is an open question about whether an actual switch in task is in fact necessary to obtain a "selection" cost asymmetry. In Experiments 1 and 2, we modified an alternating-runs paradigm to include either long or short response-to-stimulus intervals (RSIs) after each pair of trials (i.e., AA-AA-BB-BB), thereby inducing selection costs not only at the point of a task switch (i.e., AA-BB), but also between same-task pairs (i.e., AA-AA). Using spatially compatible versus incompatible response rules (Experiment 1) and Stroop word versus color naming (Experiment 2), we found asymmetric effects not only at task-change transitions, but also at task-repeat transitions when the RSI was long (presumably inducing frequent losses of set). In Experiments 3A and 3B, a cost asymmetry for long RSIs was obtained even when competing tasks were separated into alternating single task blocks, but not when the tasks were compared in a between-subjects design. This general pattern cannot be explained by activation carryover models, but is consistent with the idea that the asymmetry arises as a result of interference from long-term memory traces.

Interaction of task readiness and automatic retrieval in task switching: Negative priming and competitor priming

When subjects switch between tasks, performance is slower after a task switch than after a task repetition, even when preparation time is long. We report two experiments that support the idea that a large part of these residual task shift costs can be due to stimulus-cued retrieval of previous task episodes. We demonstrate that there are two different factors at work: (1) facilitation of response to the current distractor stimulus, appropriate to the previously relevant, competing task (competitor priming), and (2) impaired processing of previously suppressed responses (negative priming). Negative priming was contingent on the size of the stimulus set, suggesting that distractor suppression comes into effect only if the distractors are highly activated. Importantly, both types of interference interacted with task readiness: Whereas in the nondominant task (picture naming), switch and nonswitch trials were equally affected, the dominant task (word reading) showed priming effects on switch trials only. Thus, the retrieval of previous processing episodes has a selective impact on situations in which task competition is high.

Reduced Task-Set Inertia in Parkinson’s Disease

This study investigated the relationship between cognitive inhibition and set-switching costs in 13 patients with Parkinson’s disease (PD) and 16 control subjects using a set-switching task with fully predictable switches. Incongruent colour-words and numerals were presented in either baseline (only colour-words or only numerals) or alternating lists (colour-words and numerals in alternation). Words required either a word-reading or colour-naming response whereas numerals required either a value-naming (value of the digits) or group-size naming (number of digits) response. Stroop interference was found to be increased and practice effects on nondominant tasks reduced in PD patients, suggesting that the ability to increase control over interference from irrelevant prepotent responses may be implicated in PD. Switch costs of PD patients were reduced on the first few trials of alternating dominant task lists and increased towards the end of alternating nondominant task lists. Both effects were explained as resulting from a reduced ability to maintain task-sets where selection of correct responses relies on inhibition of irrelevant stimulus-response mappings.