Resilient Team Formation with Stabilisability of Agent Networks for Task Allocation

Team formation (TF) faces the problem of defining teams of agents able to accomplish a set of tasks. Resilience on TF problems aims to provide robustness and adaptability to unforeseen events involving agent deletion. However, agents are unaware of the inherent social welfare in these teams. This article tackles the problem of how teams can minimise their effort in terms of organisation and communication considering these dynamics. Our main contribution is twofold: first, we introduce the Stabilisable Team Formation (STF) as a generalisation of current resilient TF model, where a team is stabilisable if it possesses and preserves its inter-agent organisation from a graph-based perspective. Second, our experiments show that stabilisability is able to reduce the exponential execution time in several units of magnitude with the most restrictive configurations, proving that communication effort in subsequent task allocation problems are relaxed compared with current resilient teams. To do so, we developed SBB-ST, a branch-and-bound algorithm based on Distributed Constrained Optimisation Problems (DCOP) to compute teams. Results evidence that STF improves their predecessors, extends the resilience to subsequent task allocation problems represented as DCOP, and evidence how Stabilisability contributes to resilient TF problems by anticipating decisions for saving resources and minimising the effort on team organisation in dynamic scenarios.

Predictability-dependent encoding of statistical regularities in the early visual cortex

Previous research recognized that humans could extract statistical regularities of the environment to automatically predict upcoming events. However, it has remained unexplored how the brain encodes the distribution of statistical regularities if it continuously changes. To investigate this question, we devised an fMRI paradigm where participants (N = 32) completed a visual four-choice reaction time (RT) task consisting of statistical regularities. Two types of blocks involving the same perceptual elements alternated with one another throughout the task: While the distribution of statistical regularities was predictable in one block type, it was unpredictable in the other. Participants were unaware of the presence of statistical regularities and of their changing distribution across the subsequent task blocks. Based on the RT results, although statistical regularities were processed similarly in both the predictable and unpredictable blocks, participants acquired less statistical knowledge in the unpredictable as compared with the predictable blocks. Whole-brain random-effects analyses showed increased activity in the early visual cortex and decreased activity in the precuneus for the predictable as compared with the unpredictable blocks. Therefore, the actual predictability of statistical regularities is likely to be represented already at the early stages of visual cortical processing. However, decreased precuneus activity suggests that these representations are imperfectly updated to track the multiple shifts in predictability throughout the task. The results also highlight that the processing of statistical regularities in a changing environment could be habitual.

Threat Effects on Attention Networks in Individuals with a History of Externalizing Behaviors

Research identifying the biobehavioral processes that link threat exposure to cognitive alterations can inform treatments designed to reduce perpetration of stress-induced aggression. The present study attempted to specify the effects of relatively predictable (acute) vs unpredictable (diffuse) threat on two theoretically relevant attention networks, attentional alerting and executive control; and to examine the extent to which aggression proneness moderated those effects. In a sample with high rates of externalizing behaviors (n = 74), we measured event-related brain activity during an attention network test that manipulated cognitive systems activation under distinct contexts of threat (NPU manipulation). The first set of results confirmed that threat exposure alters alerting and executive control. The predictable threat condition, relative to unpredictable threat, increased visual alerting (alert cue N1) and decreased attention (P3) to subsequent task-relevant stimuli (flanker). In contrast, overall threat and unpredictable threat conditions were associated with alerting-related quicker responding and poorer conflict resolution (congruence-related flanker N2 reductions and RT interference). The second set of results indicated that different operationalizations of aggression proneness were inconsistently related to threat-related alterations in cognitive systems. While these results regarding threat-related cognitive alterations in aggression require more study, they nevertheless expand what is known about threat-related modulation of cognition in a sample of individuals with histories of externalizing behaviors.

Belief in Control: Voluntary Choice Enhances Subsequent Task Performance under Undefeated Choice-Outcome Causation

Humans are believed to have volition through which they act upon and change the external environment. As an exercise of volition, making a voluntary choice facilitates the subsequent behavioral performance relative to a forced choice. However, it is unclear how this facilitation is constrained by the perceived relationship between a choice and its outcome. In a series of experiments, participants were free or forced to choose one of two presented pictures. The outcome of the choice was then revealed, which could be always the chosen picture or always the unchosen picture (i.e., a confirmed choice-outcome causation), a blank screen with no picture at all (i.e., an unrevealed choice-outcome relation), the chosen or unchosen picture with equal probability (i.e., a defeated choice-outcome causation), or a third picture different from the two preceding options (again, a defeated choice-outcome causation). Participants then complete a visual search task with the task-irrelevant picture (or the blank screen) serving as a background. Results showed that the search performance was improved after a voluntary choice under both the confirmed causation and the unrevealed relation, but not under the defeated causation. Over individuals, the improved performance due to voluntary choice under confirmed causation positively correlated with the improved performance under the unrevealed relation, and with the reported belief in controlling the outcome of the choice. Our findings suggest that the exercise of volition motivates subsequent behavior, and this motivation is restricted to an “undefeated” choice-outcome causation which affords a belief in controlling the outcome by exerting volition.

The Roles Of Cognitive Load and Appraisal Of Task Difficulty In Predicting Subjective Fatigue And Subsequent Task Disengagement

Central fatigue refers to an inability to sustain mental or physical performance in self-initiated tasks and an increased perception of effort (Chaudhuri & Behan, 2000), suggesting that fatigue results from a mismatch between the perceived resources needed to initiate a task and the availability of cognitive resources available to complete it. Consequently, fatigue may be considered a “stop-emotion” to preserve cognitive resources, resulting in task disengagement (Meijman, 2000). This study investigated: 1) the role of perceived cognitive resources in the development of mental fatigue by manipulating the task demands and appraisals of task difficulty, and 2) the subsequent effect of fatigue on task engagement. Fatigue increased and cognitive resources decreased with time on task, rather than as a result of the task demands × instruction of task difficulty interaction. Increases in fatigue did not predict measures of engagement in almost all cases. Implications and suggestions for future research are discussed.

Effect of motivational incentives on face-name hyper-binding in older adults

Hyper-binding refers to the tendency for older adults to encode extraneous information from their environment, and bind this information to attentional targets such that this distracting information can be remembered in association with target information on a subsequent task. This tendency is hypothesized to result from a loss of selectivity in memory and attention due to a loss of inhibitory control. However, older adults do demonstrate selectivity under certain motivational conditions. For example, older adults show enhanced memory selectivity in reward-motivated states. The current study used motivational incentives (virtual rewards) to investigate the interaction between hyper-binding and reward-based motivation. Results revealed a motivation-related decrease in hyper-binding in older adults. This decrease was not affected by incentive magnitude (low versus high). These results suggest that the value-directed selectivity of memory and attention counteract the age-related selectivity deficit associated with hyper-binding. Keywords: Cognitive aging, inhibitory control, selective attention, hyper-binding, motivated cognition, reward-based motivation

The Roles Of Cognitive Load and Appraisal Of Task Difficulty In Predicting Subjective Fatigue And Subsequent Task Disengagement

Central fatigue refers to an inability to sustain mental or physical performance in self-initiated tasks and an increased perception of effort (Chaudhuri & Behan, 2000), suggesting that fatigue results from a mismatch between the perceived resources needed to initiate a task and the availability of cognitive resources available to complete it. Consequently, fatigue may be considered a “stop-emotion” to preserve cognitive resources, resulting in task disengagement (Meijman, 2000). This study investigated: 1) the role of perceived cognitive resources in the development of mental fatigue by manipulating the task demands and appraisals of task difficulty, and 2) the subsequent effect of fatigue on task engagement. Fatigue increased and cognitive resources decreased with time on task, rather than as a result of the task demands × instruction of task difficulty interaction. Increases in fatigue did not predict measures of engagement in almost all cases. Implications and suggestions for future research are discussed.

Effect of motivational incentives on face-name hyper-binding in older adults

Hyper-binding refers to the tendency for older adults to encode extraneous information from their environment, and bind this information to attentional targets such that this distracting information can be remembered in association with target information on a subsequent task. This tendency is hypothesized to result from a loss of selectivity in memory and attention due to a loss of inhibitory control. However, older adults do demonstrate selectivity under certain motivational conditions. For example, older adults show enhanced memory selectivity in reward-motivated states. The current study used motivational incentives (virtual rewards) to investigate the interaction between hyper-binding and reward-based motivation. Results revealed a motivation-related decrease in hyper-binding in older adults. This decrease was not affected by incentive magnitude (low versus high). These results suggest that the value-directed selectivity of memory and attention counteract the age-related selectivity deficit associated with hyper-binding. Keywords: Cognitive aging, inhibitory control, selective attention, hyper-binding, motivated cognition, reward-based motivation

Learning vocabulary in spoken input- and output-based tasks

This experimental study explores the differential effects of spoken input-based and output-based tasks on vocabulary knowledge. The study also investigates whether such tasks result in more learning gains than exposure to input-only (no subsequent task). The study employed a pretest-posttest design with two groups: an experimental group (n = 32) who completed both input- and output-based tasks in a counterbalanced way and a comparison group (n = 12) who were only exposed to L2 input. Vocabulary gains were measured at three levels of sensitivity: oral spontaneous use, oral form recall and meaning recall. The findings showed that participants who were only exposed to L2 input learned significantly fewer words than participants who completed the input-based and output-based tasks. No difference in learning gains was found between the input-based and output-based tasks.

Does increasing social presence enhance the effectiveness of writing explanations?

Writing explanations has demonstrated to be less effective than providing oral explanations, as writing triggers less amounts of perceived social presence during explaining. In this study, we investigated whether increasing social presence during writing explanations would aid learning. University students (N = 137) read an instructional text about immunology; their subsequent task depended on experimental condition. Students either explained the contents to a fictitious peer orally, wrote their explanations in a text editor, or wrote them in a messenger chat, which was assumed to induce higher levels of social presence. A control group retrieved the material. Surprisingly, we did not obtain any differences in learning outcomes between experimental conditions. Interestingly, explaining was more effortful, enjoyable, and interesting than retrieving. This study shows that solely inducing social presence does not improve learning from writing explanations. More importantly, the findings underscore the importance of cognitive and motivational conditions during learning activities.