Research has demonstrated that the performance of narcissists rises and falls with the opportunity for self-enhancement and the emergence of ego threats. As such, it has been suggested that narcissists are more capable of performing in a competition, where self-enhancement and ego threats are present, rather than in a training environment, where such opportunities are lacking. However, the narcissism-performance literature has focused on narcissism in its grandiose form but has not considered the so-called adaptive and maladaptive components of narcissism. Indeed, adaptive narcissism, reflecting high levels of confidence and assertiveness, is different to maladaptive narcissism, reflecting a strong willingness to dominate and control over situations. Since narcissism can reflect either high levels of adaptive or maladaptive narcissism, or certainly both, it is essential to consider adaptive and maladaptive narcissism interact in order to gain a full picture of how narcissism plays a role in performance settings. Therefore, the overarching aim of the thesis was to examine the interaction between adaptive and maladaptive narcissism in two different performance contexts, namely high-pressure performance environments and athletic training environments. Furthermore, the thesis also explored mechanisms underlying the narcissism-performance relationship in order to explain why the adaptive  maladaptive narcissism interaction would contribute to high performance under high pressure. Finally, the thesis examined practical strategies to protect against the potential adverse effects of narcissism on athlete training; providing the first evidence that goal-setting and imagery use during training help narcissists (especially those high in adaptive narcissism) train better.

The thesis consists of a general introduction (Chapter 1), four empirical studies (Chapters 2 and 3), and a general discussion (Chapter 4). More specifically, Chapter 2 presents a collection of three experimental studies, examining the interactive effects of adaptive and maladaptive narcissism on performance under pressure as well as testing the mechanisms underlying the performance effects. Experiment 1 used a basketball free throw task to assess the adaptive  maladaptive narcissism interaction on performance under high pressure. Experiment 2 used a golf-putting task to test the hypothesized performance effects. Further, Experiment 2 employed self-report and behavioural measures to explore the mechanisms underlying any performance effects. To test the replicability and generalizability of Experiments 1 and 2, Experiment 3 used a letter transformation task and a colour-word Stroop task to test the adaptive  maladaptive narcissism interaction, along with self-report and psychophysiological measures to examine mechanisms. Across each study results consistently demonstrated that adaptive narcissism predicted performance under high pressure only when maladaptive narcissism was high. Also, at high levels of maladaptive narcissism, adaptive narcissism predicted decreased pre-putt time in the golf-putting task (Experiment 2) and an adaptive psychophysiological response in the letter transformation task (Experiment 3), reflecting better processing efficiency. Findings suggest that individuals high in both adaptive and maladaptive narcissism perform better under pressure because of superior processing efficiency during task performance.

Chapter 3 (Study 4) presents an applied study examining a three-way interaction between adaptive and maladaptive narcissism and performance strategies (specifically goal-setting and imagery), on athlete quality of training. Using a sample of athletes from different backgrounds (i.e., sporting levels and sport types) with multiple-source data provided (i.e., self-report and informant rating), Study 4 demonstrated consistent three-way interactions between narcissism components and each performance strategy. Specifically, when athlete use of goal-setting was low, adaptive narcissism contributed to increased distractibility and poorer quality of preparation when maladaptive narcissism was low but not high. However, when athlete use of goal-setting was high, adaptive narcissism was not associated with training behaviours regardless of the level of maladaptive narcissism. Identical interactions also emerged for imagery use. The findings suggest that maladaptive narcissism and the performance strategies of goal-setting and imagery protect against the potential adverse effects of adaptive narcissism on athlete training.

Based on the findings of the empirical work presented in Chapter 2 and 3, Chapter 4 of this thesis provides implications at a broad theoretical and applied level. Strengths, limitations, and directions for future research are also discussed.