No description available.

No description available.

No description available.

A human factors experiment was conducted to investigate the potential benefits of using directional auditory cues in intelligent transportation system technologies in commercial vehicles. Twelve licensed commercial vehicle operators drove a commercial truck-driving simulator and were prompted to select highway numbers on a side-task display. Prompts were presented visually or aurally. Auditory prompts were presented either diotically (both ears simultaneously) or directionally (to either the left or right ear). The search task varied in map density and timing of the prompts in relation to speed limit changes. All experimental conditions were compared to a control condition containing no secondary task. Both driving performance (lane deviation, steering wheel angle, road heading angle error, accidents, and adherence to the speed limit) and secondary task performance (accuracy and response time) measures were collected. Results showed that drivers were able to respond more quickly and accurately to the search task when directional auditory cues were used. Results also showed that driving performance degrades when display density increases and that the use of directional auditory prompts lessens this deterioration of performance for high-density conditions. / Master of Science

Prolonged computer work is associated with high rates of neck and shoulder pain symptoms, and as computers have become increasingly more common, it is becoming critical that we develop sustainable interventions targeting this issue. Static muscle contractions for prolonged periods often occur in the neck/shoulder during computer work and may underlie muscle pain development in spite of rather low relative muscle load levels. Causal mechanisms may include a stereotypical recruitment of low threshold motor units (activating type I muscle fibers), characterized by a lack of temporal as well as spatial variation in motor unit recruitment. Based on this theory, although studies have postulated that individuals with chronic neck-shoulder pain will show less variation in muscle activity compared to healthy individuals when engaged in repetitive/monotonous work, this has seldom been verified in empirical studies of actual computer work. Studies have rarely addressed temporal patterns in muscle activation, even though there is a consensus that temporal activation patterns are important for understanding fatigue and maybe even risks of subsequent musculoskeletal disorders. This study applied exposure variation analysis (EVA) to study differences in temporal patterns of trapezius muscle activity as individuals with and without pain performed computer work. The aims of this study were to: Assess the reliability of EVA to measure variation in trapezius muscle activity in healthy individuals during the performance of computer work; Determine the extent to which healthy subjects differ from those with chronic pain in trapezius muscle activity patterns during computer work, measured using EVA. Thirteen touch-typing, right-handed participants were recruited in this study (8 healthy; 5 chronic pain). The participants were asked to complete three 10-minute computer tasks (TYPE, CLICK and FORM) in two pacing conditions (self-paced, control-paced), with the healthy group completing two sessions and the pain group completing one. Activation of the upper trapezius muscle was measured using surface electromyography (EMG). EMG data were organized into 5x5 EVA matrices with five amplitude classes (0-6.67, 6.67-20, 20-46.67, 46.67-100, >100% Reference Voluntary Exertion) and five duration classes (0- 1, 1-3, 3-7, 7-15, >15 seconds). EVA marginal distributions (along both amplitude and duration classes) for each EVA class, as well as summary measures (mean and SD) of the marginal sums along each axis were computed. Finally, “resultant” mean and SD across all EVA cells were computed. The reliability in EVA indices was estimated using intra-class correlation coefficients (ICC), coefficient of variation (CV) and standard error of measurement (SEM), computed from repeated measurements of healthy individuals (aim 1), and EVA indices were compared between groups (aim 2). Reliability of EVA amplitude marginal sums ranged from moderate to high in the self-paced condition and low to moderate in the control-paced condition. The duration marginal sums were moderate in the self-paced condition and moderate to high in the control-paced condition. The summary measures (means and SDs) were moderate to high in both the self-paced and control-paced condition. Group comparisons revealed that individuals with chronic pain spent longer durations of work time in higher EVA duration categories, exhibited larger means along the amplitude, duration and in the resultant, and higher EVA SD in the amplitude and duration axes as compared to the healthy group. To our knowledge, this is the first study to report on the reliability of EVA applied specifically to computer work. Furthermore, EVA was used to assess differences in muscle activation patterns as individuals with and without chronic pain engaged in computer work. Individuals in the pain group seemed to exhibit prolonged sustained activation of the trapezius muscle to a significantly greater extent than controls, even though they did not experience pain during the performance of the computer tasks (as obtained through self-reports). Thus, these altered muscle recruitment patterns observed in the pain subjects, even in the absence of task-based pain/discomfort, are suggestive of chronic motor control changes occurring in adaptation to pain, and may have implications for the etiology of neck and upper-limb musculoskeletal disorders. / Master of Science / This study aims to assess the reliability of exposure variation analysis (EVA) to measure variation in trapezius muscle activity in healthy individuals during the performance of computer work, and to determine the extent to which healthy subjects differ from those with chronic pain in trapezius muscle activity patterns during computer work, measured using EVA. Muscle activation was recorded for eight healthy individual and five suffering from chronic neck-shoulder pain. The data were then categorized into amplitude and continuous time categories, and summary measures of resulting distributions were calculated. These measures were used to assess the reliability of participant responses to computer work of healthy individuals, as well as quantify differences between those with and without chronic pain. We found that individuals with pain activated their neck-shoulder muscles for longer continuous durations than healthy individuals, thus showing an inability to relax their muscles when performing work.

Proactive organizational behavior is characterized by self-started and long-term oriented activities involving forward thinking and the intention to effect change in one's work environment. The primary objective of this research was to investigate relationships of supervisory behaviors with subordinates' personal initiative, voice behavior, and proactive service performance and to reveal moderators and mediators of these associations. Whereas personal initiative represents a wide range of proactive behaviors, voice behavior specifically reflects challenging and constructive forms of change-oriented communication. Drawing on the proactivity, service, and performance literatures, the proactive service performance construct was newly conceptualized as self-started and long-term oriented service behavior exceeding prescribed requirements.Twelve hypotheses were developed based on the implications of several leadership, performance, and motivation theories as well as previous empirical studies. Data from 229 supervisor-subordinate dyads were collected in a large financial services organization across three lines of business and ten U.S. states. Confirmatory factor analyses demonstrated that proactive service performance, voice behavior, and task performance were distinguishable performance dimensions. Participative leadership related positively and active-corrective transactional leadership negatively to supervisor ratings of subordinate proactivity. Transformational leadership was positively associated with personal initiative, proactive service performance, and task performance. In hierarchical regression analyses, the block of leadership variables explained significant increments in the variance of all criteria, after several control, subordinate, and task variables were accounted for.Moderated hierarchical regressions revealed that transformational leadership positively predicted voice only when combined with high participation or low levels of co rrective leadership. Similarly, transformational leadership was more strongly and positively associated with initiative when corrective leadership was low. Participative leadership more strongly and positively related to voice for action-oriented subordinates low in hesitation and to all proactivity criteria for subordinates low in affective organizational commitment. Mediated regression analyses as well as structural equation modelling identified trust in leadership as a mediator of most of the relationships between the leadership predictors and the proactivity criteria. The discussion focuses on practical implications for leadership development, conceptual implications for the distinction between task performance and proactivity, and directions for future research on the antecedents and consequences of proactive behavior.

The purpose of the study was to examine elements which affected students' team trust building in an online collaborative learning team and relationships among these elements. The setting of this study was a graduate-level online course on Computer Supported Collaborative Learning (CSCL) in which all course activities were conducted collaboratively through online communications. Data were collected from multiple sources including interviews which were audio taped, transcripts of students' self-reflective journals, transcripts of messages on the asynchronous web conferencing system, transcripts of messages on the synchronous web conferencing system, and the researcher's reflective journals. Data were analyzed using the coding procedures for developing grounded theory proposed by Strauss and Corbin (1998). Results of the data analysis indicated the influences of CSCL course context including the collaborative nature of the course and the heterogeneity of teams on students' team trust building. Results also indicated the dynamics of team trust building. Four different components of team trust building, which were initial team trust, contributors, dimensions, and consequences of team trust, influenced one another. Students’ initial team trust influenced the contributors to team trust which were students' competence, reliability, online communication, and caring. In addition, these contributors influenced the dimensions of team trust such as task performance trust and interpersonal trust. Once students built trust in their teams, they could develop collaborative knowledge building and a sense of community which were the consequences of team trust. The consequences of students’ team trust, in turn, influenced the contributors to team trust. Understanding the construct of team trust may help not only instructors in their design and guidance of successful online collaborative learning teams, but also students in various online collaborative learning teams. In addition, the results of this study may help instructors and researchers to consider carefully the issues in relation to online team trust building. / text

This thesis examined the intra-individual relationship between state affect and task performance, with an emphasis on a) the moderating effects of trait affect and task difficulty; and b) the mediating effects of cognitive and affective regulation. Theory and empirical research from the emotion, motivation, and personality literatures was integrated to develop a multilevel model of states, traits, and situational factors as predictors of task performance. Data from five studies were analysed using single- and multi-level techniques to test the hypothesised model of relationships. The findings are reported within three manuscripts, which comprise the body of this thesis. Manuscript 1 presents validation evidence for the psychometric instruments used to measure the self-regulatory components of the model. Three studies (N = 758) were conducted to examine the nomological network of cognitive and affective regulation. In parallel, two new self-report scales were developed to operationalise these constructs within a repeated measures paradigm. The three studies demonstrated that the new cognitive and affective regulation scales were uniquely associated with other self-regulatory, personality, affective and achievement variables at the intra-individual and inter-individual levels. Study 1 provided evidence for the unidimensionality, internal consistency, and construct validity of each scale. Study 2 replicated and extended construct validity evidence using a different sample and performance domain. Study 3 established the utility of each scale for assessing intra-individual variability in cognitive and affective regulation, and their ability to predict performance within individuals. In sum, the three studies suggested that the new measures of cognitive and affective regulation were psychometrically adequate for use in model testing. Manuscripts 2 and 3 tested the intra-individual relationship between state affect and task performance, with a focus on the moderating effects of trait affect and task difficulty (Manuscript 2), and the mediating effects of cognitive and affective regulation (Manuscript 3). Each manuscript analysed different portions of data from two laboratory experiments (N = 182). In each experiment, participants performed multiple trials of an air-traffic control simulation that varied in task difficulty at the inter-individual (Study 4) or intra-individual (Study 5) level. Trait positive and negative affect were measured before the task, whereas state positive and negative affect, cognitive and affective regulation, and task performance were measured at repeated intervals over practice. In Manuscript 2, hierarchical linear modelling demonstrated that state positive affect was positively related, whereas state negative affect was negatively related, to task performance at the intra-individual level of analysis. As hypothesised, the strength of these affect-performance relationships was significantly moderated by trait affect and task difficulty. In both studies, the positive intra-individual relationship between state positive affect and performance was stronger for individuals with high (versus low) trait positive affect, particularly when task difficulty was high (versus low). In contrast, the negative intra-individual relationship between state negative affect and performance only emerged for individuals with low (versus high) trait negative affect, regardless of the level of task difficulty. In Study 4, the intra-individual relationship between state negative affect and task performance was also more pronounced when task difficulty was high (versus low). In Manuscript 3, multilevel multiple-mediation modelling demonstrated that cognitive regulation significantly mediated the intra-individual relationship between state positive affect and performance in both studies, alongside the intra-individual relationship between state negative affect and performance in Study 4. Unexpectedly, affective regulation failed to mediate either of these affect-performance relationships. However, state positive affect was positively related to affective regulation in both studies, whereas state negative affect was positively related to affective regulation in Study 5. Overall, this thesis makes theoretical, empirical and methodological contributions to understanding how affect relates to performance at the intra-individual level of analysis; and for whom, when, and why these relationships emerge. Within a multilevel framework, it integrates interdisciplinary perspectives to identify the affective determinants of performance from two levels of analysis. The results demonstrate that state positive and negative affect can differentially predict intra-individual variability in task performance, and that these effects may a) depend on trait affect and task difficulty; and b) be partially explained by cognitive regulation. These findings emphasise the importance of adopting a multilevel, repeated measures paradigm to examine how affective states, traits, and task demands interactively predict task performance. There is scope for extending this research further by investigating a broader range of moderating and mediating constructs. Practical implications and directions for future research are discussed.

This thesis examined the intra-individual relationship between state affect and task performance, with an emphasis on a) the moderating effects of trait affect and task difficulty; and b) the mediating effects of cognitive and affective regulation. Theory and empirical research from the emotion, motivation, and personality literatures was integrated to develop a multilevel model of states, traits, and situational factors as predictors of task performance. Data from five studies were analysed using single- and multi-level techniques to test the hypothesised model of relationships. The findings are reported within three manuscripts, which comprise the body of this thesis. Manuscript 1 presents validation evidence for the psychometric instruments used to measure the self-regulatory components of the model. Three studies (N = 758) were conducted to examine the nomological network of cognitive and affective regulation. In parallel, two new self-report scales were developed to operationalise these constructs within a repeated measures paradigm. The three studies demonstrated that the new cognitive and affective regulation scales were uniquely associated with other self-regulatory, personality, affective and achievement variables at the intra-individual and inter-individual levels. Study 1 provided evidence for the unidimensionality, internal consistency, and construct validity of each scale. Study 2 replicated and extended construct validity evidence using a different sample and performance domain. Study 3 established the utility of each scale for assessing intra-individual variability in cognitive and affective regulation, and their ability to predict performance within individuals. In sum, the three studies suggested that the new measures of cognitive and affective regulation were psychometrically adequate for use in model testing. Manuscripts 2 and 3 tested the intra-individual relationship between state affect and task performance, with a focus on the moderating effects of trait affect and task difficulty (Manuscript 2), and the mediating effects of cognitive and affective regulation (Manuscript 3). Each manuscript analysed different portions of data from two laboratory experiments (N = 182). In each experiment, participants performed multiple trials of an air-traffic control simulation that varied in task difficulty at the inter-individual (Study 4) or intra-individual (Study 5) level. Trait positive and negative affect were measured before the task, whereas state positive and negative affect, cognitive and affective regulation, and task performance were measured at repeated intervals over practice. In Manuscript 2, hierarchical linear modelling demonstrated that state positive affect was positively related, whereas state negative affect was negatively related, to task performance at the intra-individual level of analysis. As hypothesised, the strength of these affect-performance relationships was significantly moderated by trait affect and task difficulty. In both studies, the positive intra-individual relationship between state positive affect and performance was stronger for individuals with high (versus low) trait positive affect, particularly when task difficulty was high (versus low). In contrast, the negative intra-individual relationship between state negative affect and performance only emerged for individuals with low (versus high) trait negative affect, regardless of the level of task difficulty. In Study 4, the intra-individual relationship between state negative affect and task performance was also more pronounced when task difficulty was high (versus low). In Manuscript 3, multilevel multiple-mediation modelling demonstrated that cognitive regulation significantly mediated the intra-individual relationship between state positive affect and performance in both studies, alongside the intra-individual relationship between state negative affect and performance in Study 4. Unexpectedly, affective regulation failed to mediate either of these affect-performance relationships. However, state positive affect was positively related to affective regulation in both studies, whereas state negative affect was positively related to affective regulation in Study 5. Overall, this thesis makes theoretical, empirical and methodological contributions to understanding how affect relates to performance at the intra-individual level of analysis; and for whom, when, and why these relationships emerge. Within a multilevel framework, it integrates interdisciplinary perspectives to identify the affective determinants of performance from two levels of analysis. The results demonstrate that state positive and negative affect can differentially predict intra-individual variability in task performance, and that these effects may a) depend on trait affect and task difficulty; and b) be partially explained by cognitive regulation. These findings emphasise the importance of adopting a multilevel, repeated measures paradigm to examine how affective states, traits, and task demands interactively predict task performance. There is scope for extending this research further by investigating a broader range of moderating and mediating constructs. Practical implications and directions for future research are discussed.

Diss. (sammanfattning) Linköping : Linköpings universitet, 2006. / Härtill 5 uppsatser.