No abstract

The dorsal and ventral aspects of the prefrontal cortex (PFC) are the two regions most consistently recruited in divergent thinking tasks. Given that frontal tasks have been shown to be vulnerable to sleep loss, we explored the impact of a single night of sleep deprivation on fluency (i.e., number of generated responses) and PFC function during divergent thinking. Participants underwent functional magnetic resonance imaging scanning twice while engaged in the Alternate Uses Task (AUT) – once following a single night of sleep deprivation and once following a night of normal sleep. They also wore wrist activity monitors, which enabled us to quantify daily sleep and model cognitive effectiveness. The intervention was effective, producing greater levels of fatigue and sleepiness. Modeled cognitive effectiveness and fluency were impaired following sleep deprivation, and sleep deprivation was associated with greater activation in the left inferior frontal gyrus (IFG) during AUT. The results suggest that an intervention known to temporarily compromise frontal function can impair fluency, and that this effect is instantiated in the form of an increased hemodynamic response in the left IFG.

N-back working memory (WM) tasks necessitate the maintenance and updating of dynamic rehearsal sets during performance. The delayed matching-to-sample (dMTS) task is another WM task, which in turn involves the encoding, maintenance, and retrieval of stimulus representations in sequential order. Because both n-back and dMTS engage WM function, we hypothesized that compared to a control task not taxing WM, training on the n-back task would be associated with better performance on dMTS by virtue of training a shared mental capacity. We tested this hypothesis by randomly assigning subjects (N = 43) to train on either the n-back (including 2-back and 3-back levels) or an active control task. Following training, dMTS was administered in the fMRI scanner. The n-back group performed marginally better than the active control group on dMTS. In addition, although the n-back group improved more on the less difficult 2-back level than the more difficult 3-back level across training sessions, it was improvement on the 3-back level that accounted for 21% of the variance in dMTS performance. For the control group, improvement in training across sessions was unrelated to dMTS performance. At the neural level, greater activation in the left inferior frontal gyrus, right posterior parietal cortex, and the cerebellum distinguished the n-back group from the control group in the maintenance phase of dMTS. Degree of improvement on the 3-back level across training sessions was correlated with activation in right lateral prefrontal and motor cortices in the maintenance phase of dMTS. Our results suggest that although n-back training is more likely to improve performance in easier blocks, it is improvement in more difficult blocks that is predictive of performance on a target task drawing on WM. In addition, the extent to which training on a task can transfer to another task is likely due to the engagement of shared cognitive capacities and underlying neural substrates—in this case WM.

This article reports an experiment using the C 3 Fire microworld-a functional simulation of command and control in a complex and dynamic environment-in which 24 three-person teams were organized according to either a functional or multifunctional allocation of roles. We proposed a quantitative approach for estimating teamwork requirements and comparing them across team structures. Two multiple linear regression models were derived from the experimental data, one for each team structure. Both models provided excellent fits to the data. The regression coefficients revealed key similarities and some major differences across team structures. The two most important predictors were monitoring effectiveness and coordination effectiveness regardless of team structure. Communication frequency was a positive predictor of performance in the functional structure but a negative predictor in the multifunctional structure. In regard to communication Downloaded from 508 Small Group Research 42 (5) content, the proportion of goal-oriented communications was found to be a positive predictor of team performance in functional teams and a weak negative predictor of team performance in multifunctional teams. Mental load was a useful predictor in functional teams but not in multifunctional teams. Results show that this method is useful for estimating teamwork requirements and support the claim that teamwork requirements can vary as a function of team structure.

Crisis management teams face situations characterized by high risk, time pressure, and uncertainty and must adapt to a wide range of circumstances. Self-organizing teams have been proposed as an alternative to more traditional functional teams as they are described as adaptive and promptly reconfigurable. This study investigated whether self-organizing teams display more role flexibility than functional teams and the impact on performance and coordination. Teams were assigned to either a functional or a selforganizing structure and completed scenarios in a functional simulation. Results revealed that self-organizing teams performed and coordinated better than functional teams. As expected, self-organizing teams showed more role variability across and within teams. However, greater variability in role allocation within teams was associated with poorer performance and coordination. We conclude that flexibility in roles can be beneficial but that too much variability can be associated with role ambiguity and negatively affect a team's ability to achieve its goals.