Theses and Dissertations

Students in academic environments receive near-constant feedback about both their own abilities as well as the performance of their peers which could significantly alter their cognitive and learning outcomes. This research investigates whether this social feedback concerning peer ability would improve students’ cognitive performance as measured by a visual working memory (VWM) task. Specifically, the present study provides either positive or negative feedback by means of peers’ performance to test for changes in the quality (memory precision) and the memorability (memory failure rate) of visual working memory representations. The effect of feedback on individual confidence was also examined, as feedback might impact subjective confidence instead of object task performance. Memory precision, participant guess rate, and confidence were compared across both halves of the experiment to determine potential time differences. Participants (N=105) were each administered a 300-trial Delayed Estimation Task to assess visual working memory ability. Participants were asked to rate their confidence in their task response after each trial and were all informed of their own response accuracy after every block of 30 trials. Along with personal feedback after each block, individuals were randomly assigned to view feedback ranking their performance as more or less accurate than other students. Results indicate a nonsignificant effect of peer feedback type on individual memory precision, guess rate, and confidence, which ran contrary to experimental hypotheses. These trends could have occurred due to the presence of participant-based moderating factors that could impact how certain individuals respond to feedback. Additionally, significant increases in both the precision of participants’ memory representations and the rate at which they guessed on the Delayed Estimation Task were observed across time. Together, these findings highlight the need for further research on the nuanced effects of social feedback on neural processing in order to improve student cognition over time.

ADHD is a neurodevelopmental disorder associated with a high rate of comorbidity with anxiety disorders (25-34%). Children with ADHD experience serious adverse outcomes secondary to impairment in executive function, particularly within the domain of working memory (WM), behavioral inhibition (BI), and sustained attention (SA). While executive function deficits in ADHD are well documented, whether and how comorbid anxiety affects cognitive performance are equivocal. One potential explanation is that most studies examine linear relations, yet evidence suggests that anxiety affects performance in a non-linear (quadratic) manner, consistent with the the Yerkes-Dodson Law. The aim of this study was to investigate whether 1) children with ADHD show deficits in WM, BI, and SA relative to typically developing children, 2) comorbid anxiety displays a linear or nonlinear relationship with WM, BI, and SA performance among children with ADHD and 3) between group differences in cognitive performance vary based on levels of anxiety. Linear and non-linear relations between anxiety and cognitive performance were assessed in a sample of 54 boys diagnosed with ADHD and 50 typically developing boys. Anxiety was assessed across dimensions and raters. Results indicate rater and domain-specific effects of comorbid anxiety on cognitive performance. Non-linear relations between children’s self-rated physiological anxiety and Phonological working memory (PHWM), Visuospatial working memory (VSWM), and the Central Executive (CE) were found. Non-linear relations between parent-rated anxiety and PHWM and the CE were also found. However, no significant linear or non-linear effects of anxiety on BI and SA were found. The results indicate that children with moderate self-rated and parent-rated anxiety performed better on WM measures relative to those with low and high levels of self-rated and parent-rated anxiety. The present study was the first to examine and document non-linear effects of anxiety on cognitive performance among children diagnosed with ADHD. Given the results, clinicians should continue to assess anxiety during diagnostic screening in ADHD samples. Treatments should focus on compensating for CE abilities and mitigating high levels of anxiety as it may further impair WM.