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Both sleep deprivation and loss of situation awareness (SA) have been cited as primary causal factors contributing to the accident and injury rate in the military and civilian sector (e.g., transportation). Despite the numerous references to both factors as causal in nature, much of the literature on the effects of sleep deprivation on executive function is anecdotal. Research has produced mixed results regarding the nature and extent of performance degradation on a variety of lower-level and executive function tasks. Similarly, although SA has been cited as a significant contributor to operational performance, there is still considerable debate over the definition and construct validity of SA. Thus, a 29-hour hour sleep deprivation study was conducted to analyze the effects of sleep deprivation on both lower-order cognitive tasks (e.g., attention and working memory) and executive function tasks (e.g., reasoning, planning, decision making, and SA). In conjunction with the sleep deprivation analysis, the relationships among lower level cognition, executive function, and situation awareness were analyzed to form hypotheses about the SA construct and its relationship to complex task performance. Forty-eight participants were administered a series of cognitive tasks during baseline and sleep deprived testing sessions. Paired t-tests and additional post hoc analyses were conducted to determine the effects of sleep deprivation on cognition. Regression and factor analysis were used analyze the relationship among lower-order cognition, executive function, situation awareness, and complex task performance. Paired t-test results showed degraded vigilance in response to sleep deprivation, but did not indicate degraded executive function. Results of additional post-hoc analyses on executive function data indicated a trend toward degraded decision making and a trend toward increased planning errors in response to sleep deprivation. The results of the regression and factor analyses provided initial support for a dynamic, process definition of SA and illustrated the importance of considering SA as part of information processing as a whole in order to improve performance prediction. Based on the results of this dissertation, engineering recommendations were made for developing an "ideal" SA measurement technique and improving existing SA measurement techniques. Additionally, future sleep deprivation and situation awareness research directions were suggested. / Ph. D.

Episodic memory is a critical component of human cognition. Episodic memory involves recollection of the contextual details surrounding an event, the capacity for mental time travel of past and future events, and is characterized by the subjective awareness that an event has been personally experienced. It is fundamental to our understanding of this complex memory system to examine how episodic memory emerges during the course of development. The present investigation explored the developmental improvement in episodic memory processing assessing recollection of factual information and the source of this information (i.e., source memory) between early to middle childhood. The electrophysiological (EEG) correlates of fact and source memory processing and measures of executive function were also examined as potential sources of variation in episodic memory. The focus of Study 1 was to examine source memory development in early childhood in a sample of 4- and 6-year-olds. Results revealed that older children were better able to recall both fact and source information. Source memory measures were correlated to early executive ability, namely measures of working memory, inhibitory control and set-shifting. Frontal EEG accounted for unique variation in fact recall but not source recall, whereas temporal EEG did not predict fact or source recall performance. The focus of Study 2 was to examine source memory development in middle childhood in a sample of 6- and 8-year-olds. Older children were better on fact recall, but both ages were comparable on source recall. Frontal EEG uniquely predicted fact recall performance beyond the contribution of age and language. Both frontal and parietal EEG and executive function predicted variation in source recall performance. In contrast, temporal EEG did not uniquely predict fact or source recall performance. Lastly, Study 3 was a longitudinal investigation of source memory between early and middle childhood. Although age-related increases in performance were evident, Time 1 and Time 2 source memory measures were not correlated. This investigation contributes to our understanding of the developmental changes in source memory processing between early and middle childhood, and identifies that patterns of frontal and parietal brain activity and executive function skills contribute to early episodic memory formation. / Ph. D.

Inhibitory control is vital to typical development and matures rapidly throughout early childhood. Inhibitory control deficits are seen in both autism spectrum disorders and attention-deficit/hyperactivity disorder and, along with other executive functions, inhibitory control contributes to school success. The tasks used to measure and stress these skills in children have not been fully explored. Even given the cognitive development levels of young children, the current inhibitory control tasks for preschoolers are not completely comparable to the tasks used with adults. For my thesis study, I added a mixed condition to the day/night inhibitory control task in preschool children using methodological design features from the Dimensional Change Card Sort (DCCS) Task. This addition allowed the day/night task to serve as a better analogue to the Stroop task, which is an inhibitory control task commonly used with adults. In addition, electroencephalogram (EEG) illuminated the neural patterns of the task in children at age four. This study demonstrated that the borders condition of the day/night task is an appropriate executive function task that can be used with preschool aged children. / Master of Science

Purpose. The purpose of this analysis was to determine if executive function affected reading assessment stability variably in online and in-person administration formats. Method. Participants (n = 67, ages 7-9) completed executive function assessments and then completed reading assessments at two different time points in order to establish pre- test/post-test assessment validity. Participants completed reading assessments in one of three conditions: all in-person, in-person and subsequently online, or all online. Executive function performance was categorized as “good” or “poor” and pre/post reading assessment correlations were calculated. Data was subsequently grouped into four general areas of reading: rate, accuracy, comprehension, and phonological awareness. Analyses were carried out to determine if pre/post reading component correlations were significantly predicted by executive function performance and assessment administration group. Additional variables included in analysis were age, gender, and study group. Results. Linear regression models and subsequent one-way analysis of variance (ANOVAs) did not indicate that pre-test/post-test reading component correlations were significantly predicted by executive function within the context of administration groups. Age, gender, and study group were also not found to significantly predict the correlation values. However, phonological awareness correlations were shown to be significantly predicted by administration group. Wherein participants in the in-person administration group tended to have higher correlation values compared to the online administration group. Reading assessment correlation to executive function was then confirmed to be in-line with current literature. Conclusion: Analyses of executive function categorization across administration group was not shown to be a significant predictor of pre/post reading component correlations. This suggests that online administration of behavioral assessments exhibits similar stability to administration of assessments in-person. Moreover, this also suggests that individuals who struggle with executive function deficits are not significantly more likely to have their performance negatively impacted on these assessments. Limitations and future study directions are also discussed.

Using neutral and emotional faces as stimuli, the Emotional Continuous Performance Task (EMO-CPT) was designed to measure both “cold” and “hot” executive functions. It was predicted that neutral stimuli would be associated with “cold” circuit functions such as sustained attention and response speed, while emotionally-laden EMO-CPT stimuli would be associated with “hot” circuit functions such as emotional judgement and response inhibition. Twenty-one male and 56 female university students (M = 21.57 years; SD = 3.15) completed the EMO-CPT, Counting Stroop (CS), Balloon Analogue Risk Task (BART), Behaviour Rating Inventory of Executive Function (BRIEF), and a demographic survey. The EMO-CPT consisted of 240 trials counterbalanced into 8 separate blocks of neutral, happy, and angry faces, with 1500ms and 3000ms stimulus intervals. Principle axis factor analysis with orthogonal (varimax) rotation revealed “Sustained/Speed” (SS; Eigenvalue = 4.26) and “Accuracy/Inhibition” (AI; Eigenvalue = 2.49) factors accounting for 48.75% of the total variance. The SS factor was modestly correlated with the BRIEF Metacognitive Index (MI; r=.25), and both the Sustained/Speed factor (r=.27) and the Accuracy/Inhibition factor (r=.25) were modestly correlated with the BRIEF Behavioural Regulation Index (BRI). As predicted, “cold” Counting Stroop reaction time variables were related to the Sustained/Speed factor (r’s .30 to .36), and the “hot” BART adjusted inflations SD were related to the Accuracy/Inhibition factor (r = -.22). Correlated with the CS and BRIEF MI, the Sustained/Speed factor appeared to tap “cold” dorsal circuit functions, while the Accuracy/Inhibition factor appeared to be related to “hot” ventral circuit functions. / Graduate

The purpose of this study was to examine the effect of yoga on children’s executive function and selective attention. There were three primary aims of this study. The first aim was to examine whether yoga would have a positive effect on children’s selective attention in a school setting. Another aim was to explore if teachers will report an improved change in children’s executive function in the classroom. The final aim was to determine if yoga would be a socially acceptable intervention to teachers and students. Participants included three fifth grade students and two teachers. Mixed methods were used to visually analyze selective attention data using a Multiple Probe Across Participants Multiple Baseline design, as well quantitative analysis of executive functioning data and qualitative analysis of social validity data. Results indicated that no functional relations were found between selective attention and yoga and no significant differences were found on pre-post measures of executive functioning. Improvements were seen when descriptive data was analyzed for dependent variables and the intervention was determined to be socially acceptable to teachers and students. Implications from the findings and recommendations for future research are presented.

While memory is the faculty that affords us learning, adaptation and development, it is our executive function that oversees, manages and organizes these abilities. Still, there is limited research on the interaction between memory and executive function. The present study investigated this relationship through Principal Components Analysis. Performances on accepted measures of memory and executive function were evaluated in an adult clinical sample. Components were retained using three criteria: a predetermined four-component structure, eigenvalues exceeding a value of one, and parallel analysis. Results demonstrated that a four-component model most accurately represented the data. Analyses also revealed that measures of immediate and delayed memory did not uniquely assess memory but instead loaded onto components associated with visual and verbal processing. The findings were shown to be in support of the brain working in an integrated, systematic manner in which abilities hierarchically ascend from arousal to tertiary function. Consequently, several accepted measures of memory and executive function failed to measure cognitive capacity unique from visual and verbal processing, placing their construct validity and efficacy in question.