The current dissertation investigated the influence of trait anxiety on the effectiveness and efficiency of select executive functions. Anxiety is an aversive emotional experience, comprised of both cognitive (e.g., worrisome thoughts) and somatic (e.g., racing heartbeat) symptomatology. Anxiety is also classified as being either trait- (i.e., chronic, enduring) or state-based (i.e., acute, transient). Executive functions are separable processes involved in the coordination and maintenance of goal-oriented behaviour. These processes operate in novel situations and are ubiquitous to daily functioning and achievement. Despite anxiety being one of the most common mental health concerns in Australia, as well as being associated with impairments in executive functioning, little research has extended beyond a select series of simple executive functions. The current work aimed to evaluate the influence of trait anxiety on a series of executive functions that had not been adequately examined in prior research. Specifically, focus was given to the functions of mental rotation, forward planning, hot and cold decision-making, and sustained attention. The current work further aimed to examine the moderating influence of other sources of cognitive interference, including variations in situational stress and cognitive load. In the later stages of this research, the role of working memory capacity was also investigated. The theoretical framework of the present work was informed by the cognitive interference model, attentional control theory. The predictions of this theory were extended to examine its application amongst complex, multifaceted executive processes.
The current dissertation consisted of two research phases. Phase 1 examined the influence of trait anxiety, situational stress, and cognitive load on the performance of mental rotation (Study 1), forward planning (Study 2), cold decision-making (Study 3), and sustained attention (Study 4). Phase 2 investigated the effect of trait anxiety, situational stress, and working memory capacity in relation to performance of forward planning (Study 5), hot decision-making (Study 6), and sustained attention (Study 7). Per the theoretical framework of the selected attentional control theory, a non-clinical sample was recruited for both phases of research. Eligible university students were recruited for the research from the campus of Bond University. Also following the framework of attentional control theory two key outcome variables were assessed across both phases: (1) performance effectiveness and (2) processing efficiency. Performance effectiveness represented the quality of performance and was indexed as task accuracy. Processing efficiency evaluated the relationship between performance effectiveness and the associated use of cognitive resources (often interpreted as reaction time [RT]). Performance efficiency in the current work was therefore estimated as a ratio of standardised performance effectiveness by standardised RT.
Hypotheses for the first phase of research a predicted three-way interaction amongst trait anxiety, situational stress, and cognitive load in influencing the select executive functions. It was specifically predicted that a combination of high trait anxiety and low cognitive load would be associated with greater effectiveness and efficiency for participants allocated to a high stress condition. Results returned partial support for these predictions, which were interpreted with respect to prior literature and theory.
Cognitive load was only found to alter performance effectiveness and processing efficiency in Study 1, which examined mental rotation. Mental rotation was assessed using a mental rotation task that adopted the seminal paradigm of Shepard and Metzler (1971). A three-way interaction between all study variables was found for mental rotation effectiveness and efficiency. At higher levels of cognitive load, high trait anxious participants who experienced a stress induction outperformed low trait anxious participants who experienced the same conditions. The influence of cognitive load only appearing in relation to mental rotation, and not any of the other Phase 1 functions, was attributed to the more simplistic procedure of the mental rotation task. That is, cognitive load exerted a noticeable change on performance only on tasks of relatively simple executive functions. By contrast, the impact was not observed for more demanded or multifaceted tasks like those examined in Study 2, 3, or 4.
In Study 2, forward planning ability was evaluated using a computerised one-touch Tower of London task. It was found trait anxiety and situational stress interactively influenced forward planning processing efficiency. When undergoing a stress manipulation, high trait anxiety participants demonstrated poorer processing efficiency (standardised accuracy/RT ratios) compared to low trait anxiety participants. Cognitive load was unrelated to processing efficiency. For performance effectiveness, situational stress alone was found to be significant, with participants in the control condition outperforming their counterparts who experienced a stress induction. Cognitive load and trait anxiety were found to be unrelated to forward planning effectiveness in this study.
Study 3 found the independent influence of trait anxiety and situational stress on the performance effectiveness of cold decision-making (i.e., logical, non-emotive decision-making). Decision-making ability was assessed using a novel task inspired by the Applying Decision Rules subtest of the Adult Decision-Making Competence battery (Bruine de Bruin, Parker, & Fischhoff, 2007). Analyses found high trait anxiety participants demonstrated greater performance effectiveness during the decision-making task compared to low trait anxiety participants. Further, participants assigned to the control condition performed with greater performance effectiveness compared to those who underwent a stress manipulation. Cognitive load had no significant contribution to performance effectiveness. No significant influence of trait anxiety, situational stress, or cognitive load were observed for processing efficiency.
Study 4 examined sustained attention ability; however no significant results were observed. Sustained attention was evaluated using a 7-minute rapid visual information processing task. Analyses suggested trait anxiety, situational stress, and cognitive load had no significant influence on the performance effectiveness or processing efficiency of sustained attention. On review, potential limitations of the chosen task and outcome measures that could have contributed to the null result were discussed. These limits were amended for the second phase of research.
In the second phase of research, the influence of trait anxiety, situational stress, and working memory capacity on the functions of forward planning, hot decision-making, and sustained attention was examined. Studies were theoretically framed within attentional control theory. Akin to the first phase of research, a non-clinical sample of eligible university students was recruited from Bond University. Hypotheses for the second phase of research were informed by attentional control theory. It was anticipated that three-way interactions between trait anxiety, situational stress, and working memory capacity would influence both performance effectiveness and processing efficiency outcome measures. Specifically, a combination of high trait anxiety and high working memory capacity would be related to better effectiveness and efficiency outcomes for participants allocated to a high stress condition. Results of the research found partial support for these predictions. All findings were ultimately reviewed in relation to attentional control theory and previous literature.
Study 5 assessed forward planning ability using a N-puzzle task. Analyses found trait anxiety, situational stress, and working memory capacity interactively influenced forward planning processing efficiency. In situations of induced stress, and when observing participants with high working memory capacity, those with high trait anxiety demonstrated improved processing efficiency compared to low trait anxiety participants. No significant effects were found for the performance effectiveness outcome.
Study 6 investigated hot decision-making (i.e., quick, emotive decision-making) using a modified Iowa gambling task. Variations in trait anxiety, situational stress, and working memory capacity were found to be unrelated to hot decision-making effectiveness or efficiency. Results were interpreted with respect to prior literature and theory. Discussion of results suggested incompatibility of task measures or ineffective stress manipulations might have contributed to inconsistency with previous research.
Study 7 examined sustained attention using the Test of Variables of Attention. With this task, performance effectiveness and processing efficiency calculations integrated the use of the sensitivity index d’. Trait anxiety, situational stress, and working memory capacity were found to interactively influence performance effectiveness and processing efficiency of sustained attention. For participants with a high working memory capacity who underwent the situational stress manipulation, those who self-reported high trait anxiety demonstrated improved performance effectiveness (i.e., target sensitivity; d’) and process efficiency compared to low trait anxiety participants in the same circumstances.
Ultimately, the summarised conclusions of the current research included (1) trait anxiety and situational stress impaired performance on tasks of executive functions that were complex and multifaceted, (2) trait anxiety and situational stress interacted to determine planning performance (3) trait anxiety and situational stress influenced logical, non-emotive decision-making over heuristic, risk-based decision-making (4) trait anxiety and situational stress interacted to determine target sensitivity during sustained attention, (5) cognitive load did not reliably alter the influence of trait anxiety and situational stress on complex executive functions, and (6) working memory capacity buffered the impairments of trait anxiety and situational stress on complex executive functions, as well as provided facilitating effects under certain circumstances. Findings of the current research contributed to a scarce area of literature and established a foundation for new work to be built upon. In the final discussion, results were compared to prior literature and interpreted within the framework of attentional control theory. The work was generally complementary to the extension of attentional control theory over a range of complex executive functions. Limitations of the project were highlighted, including restricted participant recruitment (resulting in a primarily university-based sample), gender imbalance, and emphasis on cognitive anxiety symptomatology to the exclusion of somatic symptomatology. Directions for future research were suggested with consideration of these limits. Practical implications of the work were also discussed.