Fine-motor skills in any domain (e.g., sports, surgery, music) are subject to performance decrements under pressure. A large majority of studies that have examined “choking under pressure” used golf putting as a paradigm to test participants. Golf putting is a fine-motor skill that is highly susceptible to deviations in performance, yet a skill that appears to be deceptively simple without a steep learning curve. The following thesis contained three studies that examined the influence of social evaluative threat on the objective outcome performance (holed or not holed, distance to the hole), as well as the kinematic variables associated with the putting stroke itself. Performance was measured using a high-speed infrared camera called the TOMI® which collected real-time 3D data about a number of different kinematic parameters for each putt that was struck. While it was expected that a learning effect would characterize the longitudinal trajectory of performance, it was also expected that state anxiety would moderate this trajectory. In Study 1, 35 amateur golfers, completed a self-report measure of state anxiety and performed golf putting tasks under a neutral condition followed by a social-evaluative condition. Somatic anxiety was related to differential performance trajectories, while cognitive anxiety was associated with variability in the backstroke. In Study 2, 27 beginner participants participated in an improved design based on Study 1. Somatic anxiety temporarily moderated performance under pressure for the novices. In Study 3, 55 beginner participants were recruited and randomized to either a stress-free learning task (n = 29), or a social-evaluative learning task (n = 26), to address research limitations from the first two studies. Furthermore, methodological concerns present in both Study 1 and 2 were addressed, with the aim of contributing to the debate surrounding theoretical mechanisms of how performance decrements occur, specifically under social-evaluative threat. High levels of somatic anxiety moderated the objective performance trajectory of the experimental group, and surprisingly decreased the amount of time taken to prepare for each putt in the social-evaluative task. In all three studies, somatic anxiety significantly moderated both objective and indirect performance (as indicated by kinematics and routine time). Taken together, these studies suggest that one’s interpretation of physiological symptoms while under social evaluative threat can temporarily impair performance trajectories of a fine-motor skill.

This thesis examines the validity of polyvagal theory as a model of normal socio-emotional responding (Porges, 1995, 2001, 2003a). Polyvagal theory makes several claims, and to date many of its predictions lack empirical testing. In the current research, five main hypotheses stemming from polyvagal theory were identified and tested using healthy participants. The initial empirical study examined the influence of laboratory stressors on autonomic function. The findings revealed that social evaluative threat increases activation of the sympathetic nervous system more than a virtual reality maze, and that arousal remains elevated for longer during anticipation of social evaluative threat in comparison to recovery from social evaluative threat. The second study investigated the effects of emotion regulation strategies on autonomic function, and highlighted the effectiveness of two meditation practices in reducing defensive physiological arousal and increasing subjective positive emotion. These studies were followed with a set of studies designed to evaluate the effects of defensive physiological arousal on socio-emotional functioning, as a direct test of polyvagal theory. The first study examined the effects of a laboratory stressor on facial expressivity, revealing that social evaluative threat had little impact on expressive regulation. A second study investigated the effects of a laboratory stressor on emotional sensitivity and spontaneous facial mimicry. Some limited support was found for polyvagal theory, although neither emotional sensitivity nor facial mimicry was significantly affected by laboratory stress. A final empirical study investigated the effects of a laboratory stressor on affiliation tendencies. The laboratory stressor did not influence participants’ willingness to spend time with others, however the experiment did reveal significant relationships between markers of social safeness and affiliation. The overall conclusion of this thesis is that polyvagal may not be a representative model of socio-emotional functioning in healthy participants. The implications of these findings are discussed in relation to the validity of polyvagal theory as a universal model of socio-emotional responding.