Date of Award

Fall 5-2016

Degree Type


Degree Name




Major Professor

Dr. Elliott Beaton

Second Advisor

Dr. Connie Lamm


Ten to 15% of the population is temperamentally shy and have elevated physiological stress responses to novel social situations. Yet, the neural mechanisms underlying this personality trait are not fully understood (Beaton et al., 2009; Schmidt et al., 1997). Efficiently attending to, acting on, and remembering relevant stimuli and filtering out less important information is critical given the sheer volume of sensory and perceptual stimuli the brain is exposed to.

Relevant stimuli that garner attention are remembered and consolidated with existing memories. Stimuli that do not warrant extended attention are ignored or habituated to in a process underpinned by cortical and subcortical inhibitory brain networks that reduce processing load on finite attentional resources (Freedman et al., 1991; Adler et al., 1998). Inefficient filtering of irrelevant stimuli could underpin anxiety in those with temperamental shyness and anxiety (Aron, Aron, & Davies, 2005). We measured the P50 auditory event-related potential (ERP) using a paired auditory click paradigm, as well as self-reported social anxiety and shyness, and salivary cortisol in two groups of healthy young adults selected for being very shy or very gregarious. While shy and gregarious groups demonstrated a similar P50 ERP to sound one (S1), the shy group showed elevated P50 amplitudes in response to the second sound (S2) compared to the gregarious group. Participants categorized as being lower or higher on social anxiety displayed a reverse pattern: those higher in social anxiety had a reduced response to S1 compared to those lower in social anxiety, yet a similar response to S2. Further, higher salivary cortisol predicted smaller differences and larger ratios in the P50 ERP from S1 to S2.


The University of New Orleans and its agents retain the non-exclusive license to archive and make accessible this dissertation or thesis in whole or in part in all forms of media, now or hereafter known. The author retains all other ownership rights to the copyright of the thesis or dissertation.