This study examines the effects of task complexity on second language (L2) pronunciation accuracy and global pronunciation measures in pronunciation-unfocused tasks and assesses the relationship between acoustic and listener-based pronunciation measures. Eighty-two Catalan/Spanish learners of English performed simple and complex versions of a problem-solving monologic speaking task, for which the oral stops /p, t, k/ and vowel contrasts /iː/-/ɪ/ and /æ/-/ᴧ/ were embedded in the lexical items used to perform the task. Pronunciation accuracy was gauged through acoustic measurements of laryngeal timing (voice onset time), vowel contrastiveness and nativelikeness (Mahalanobis distances), and native speakers’ ratings of comprehensibility and accentedness. Results revealed detrimental effects of increased task complexity on the productions of oral stops and speech comprehensibility and accentedness; however, no consistent task complexity effects were found on vowel accuracy. The analysis also revealed an association between segmental accuracy and global dimensions of L2 speech.

The last three decades have seen significant development in understanding and describing the effects of task complexity on learner internal processes. However, researchers have primarily employed behavioral methods to investigate task-generated cognitive load. Being the first to adopt neuroimaging to study second language (L2) task effects, we aimed to provide novel insights into the neural correlates of task-related variation in L2 oral production. To advance research methodology, we also tested the utility of a neuroimaging technique, functional magnetic resonance imaging (fMRI), in examining the impact of task-related variables on L2 speech production when combined with cognitive–behavioral tools (speech analysis, expert and learner judgments). Our research focus was the effects of task complexity on silent pausing. Twenty-four Japanese learners of English completed eight simple and complex versions of decision-making tasks, half in their first language and half in their L2. The dataset for the present study included the L2 speech and fMRI data, expert judgments, and participants’ difficulty ratings of the L1 and L2 tasks they completed. Based on our findings, we concluded that brain imaging and L1 task difficulty ratings were more sensitive to detecting task complexity effects than L2 self-ratings and pausing measures. These results point to the benefits of triangulating cognitive and neural data to study task-based neurocognitive processes.

To understand the extent to which employees choose to improvise under authoritarian leadership, we applied social information processing theory to examine the mechanisms and boundary conditions of such leadership’s influence on subordinates’ perceptions of managerial intolerance of errors and their improvisation from the perspective of negative leadership. Data from a multi-wave questionnaire survey of 319 frontline teams analysed using SPSS and Mplus revealed that authoritarian leadership can have an inhibitory effect on subordinates’ improvisation due to perceiving managerial intolerance of errors. Even so, the negative mediating effect is significantly weakened by the moderating effect of a leader–member exchange (LMX) relationship and task complexity. That is, when the level of the LMX relationship or task complexity is high, it mitigates authoritarian leadership’s indirect inhibitory effect on subordinates’ improvisation via their perceptions of management’s intolerance of errors.

Predicting mental workload of pilots can provide cockpit designers with useful information to reduce the possibility of pilot error and cost of training, improve the safety and performance of systems, and increase operator satisfaction. We present a theoretical model of mental workload, using information theory, based on review investigations of how effectively task complexity, visual performance, and pilot experience predict mental workload. The validity of the model was confirmed based on data collected from pilot taxiing experiments. Experiments were performed on taxiing tasks in four different scenarios. Results showed that predicted values from the proposed mental workload model were highly correlated to actual mental workload ratings from the experiments. The findings indicate that the proposed mental workload model appears to be effective in the prediction of pilots’ mental workload over time.

In this study we examined linguistic and non-linguistic control mechanisms in 20 Spanish–English neurologically healthy bilingual adults and 13 Spanish–English bilingual adults with aphasia. Participants completed two linguistic and two non-linguistic control tasks accounting for low and high complexity. Healthy bilingual results were indicative of domain general cognitive control, whereas patient results were indicative of domain specific cognitive control. The magnitude of conflict required to complete the tasks was also examined. Healthy bilinguals exhibited significant amounts of conflict on all tasks and linguistic and non-linguistic conflict ratios were correlated; whereas patient results revealed significant conflict only on non-linguistic tasks and those conflict ratios were not correlated with linguistic conflict ratios, indicating a dissociation between how patients are controlling information in these two domains. Finally, a relationship between language impairment and language control was identified and brain damage was associated with linguistic and non-linguistic task performance.

Organizational decision making requires the ability to process ambiguous information while dealing with overload and conflicting requirements. Although researchers agree that ambiguity tolerance is a critical skill for making high-quality complex decisions, few have investigated the effects of ambiguity tolerance on self-efficacy to make complex decisions. In the current experiment, 151 participants were randomly assigned to either a moderate complexity or high complexity decision task. Ambiguity tolerance moderated the relationships between task complexity and self-efficacy, and between task complexity and the accuracy of self-efficacy in predicting future performance. In the highly complex task, individuals with a higher tolerance for ambiguity reported higher self-efficacy and more accurate self-efficacy versus individuals with lower tolerance for ambiguity. In the moderately complex task, tolerance for ambiguity had no effects on self-efficacy or accuracy. Implications for research and practice are presented, along with study limitations.

Estimating robot performance in human robot teams is a vital problem in human robot interaction community. In a previous work, we presented extended neglect tolerance model for estimation of robot performance, where the human operator switches control between robots sequentially based on acceptable performance levels, taking into account any false alarms in human robot interactions. Task complexity is a key parameter that directly impacts the robot performance as well as the false alarms occurrences. In this paper, we validate the extended neglect tolerance model for two robot tasks of varying complexity levels. We also present the impact of task complexity on robot performance estimations and false alarms demands. Experiments were performed with real and virtual humanoid soccer robots across tele-operated and semi-autonomous modes of autonomy. Measured false alarm demand and robot performances were largely consistent with the extended neglect tolerance model predictions for both real and virtual robot experiments. Experiments also showed that the task complexity is directly proportional to false alarm demands and inversely proportional to robot performance.

Behavioral studies have shown that two different morphed faces belonging to the same identity are harder to discriminate than two faces stemming from two different identities. The temporal course of this categorical perception effect has been explored through event-related potentials. Three kinds of pairs were presented in a matching task: (1) two different morphed faces representing the same identity (within), (2) two other faces representing two different identities (between), and (3) two identical morphed faces (same). Following the second face onset in the pair, the amplitude of the right occipitotemporal negativity (N170) was reduced for within and same pairs as compared with between pairs, suggesting an identity priming effect. We also observed a modulation of the P3b wave, as the amplitude of the responses for within pairs was higher than for between and same pairs, suggesting a higher complexity of the task for within pairs. These results indicate that categorical perception of human faces has a perceptual origin in the right occipitotemporal hemisphere.

In this study, we investigated 2 possible mechanisms by which interhemispheric interaction (IHI) might facilitate performance. Twenty university students performed 3- and 4-item versions of a less complex physical identity (PI) task in which they decided whether 2 letters were perceptually identical (e.g., ‘A’ and ‘A’) and a more complex name identity (NI) task in which they decided whether 2 letters had the same name (e.g., ‘A’ and ‘a’). Consistent with prior work, IHI facilitated performance more for the relatively complex NI task than for the simpler PI task regardless of how many items were in the display. However, for each task IHI facilitated performance less in the 4-item displays than in the 3-item displays. These results indicate that IHI facilitates performance by allowing (1) a division of processing across the hemispheres, and (2) task-relevant information to be processed by a hemisphere that receives a relatively light processing load. (JINS, 2000, 6, 313–321.)