This study compared the impacts of actual individual task competence, speaking time and physical expressiveness as indicators of verbal and nonverbal communication behavior, and likability on performance evaluations in a group task. 164 participants who were assigned to 41 groups first solved a problem individually and later solved it as a team. After the group interaction, participants' performance was evaluated by both their team members and qualified external observers. We found that these performance evaluations were significantly affected not only by task competence but even more by speaking time and nonverbal physical expressiveness. Likability also explained additional variance in performance evaluations. The implications of these findings are discussed for both the people being evaluated and the people doing the evaluating.

Research Doctorate - Doctor of Philosophy (PhD) / In Chapter 1, I describe social competence, task competence and self-protection in an organisational context. In Chapter 2, I review key self theories and relate them to the self-competence construct. In Chapter 3, I review the research on self-competence to show that there is a need for a construct of social competence and self-protection. I discuss the limitations of three self-competence theories: Bandura’s (1977) self-efficacy theory, Williams and Lillibridge’s (1992) self-competence theory and Tafarodi & Swann’s (1995) self-competence/self-liking theory. In Chapter 4, I present my selfcompetence model. I raise the research questions and specify my hypotheses. In Chapter 5, I describe the construction of Social and Task Competence Scale. I present evidence of the reliability and factor structure of the Social and Task Competence Scale. I concluded that scale revisions were needed. In Chapter 6, I present evidence of the reliability, factor structure and predictive validity of the revised Social and Task Competence Scale and Self-Protection Scale. I describe the results of an experiment that investigated the interaction of task setting, social competence, task competence and selfprotection. I concluded that the measures predicted performance. In Chapter 7, I investigate the factor structure and reliability of the revised Social and Task Competence Scale and revised Self-Protection Scale. I provide evidence of the convergent and discriminant validity of these measures with reliable measures of self-competence, selfesteem, self-monitoring, personality and social desirability. In Chapter 8, I investigate the factor structure and reliability of the Social and Task Competence Scale and Self-Protection Scale after final revisions and show that these measures are acceptable for use in scientific research. I present evidence of their convergent validity with a valid andreliable measure of emotional intelligence, and describe experimental results that supported the hypothesised relationships between perceived task difficulty, social competence, task competence and self-protection and task performance. In Chapter 9, I discuss the implications of my research for self-competence theory, self-regulation and self-esteem and the prediction of social and task performance in organisations.