Dissertation Defense: Shady El Damaty
Candidate Name: Shady El Damaty
Advisor: John Van Meter, PhD.
Title: Adolescent Neurocognitive Maturity Mediates Paths to Altered Social Norms and Vulnerability in Emerging Adulthood
The present work employs a computational cognitive neuroscience approach to chart adolescent neurocognitive maturity in the context of social and environmental factors influencing paths to adverse outcomes in emerging adulthood. The rate of risk accrual was charted longitudinally during adolescence and found to predict future violent outcomes independently of the Behavioral Inhibition and Approach Systems (BIS/BAS) scales, a classic behavioral instrument for measuring adolescent cognitive development. Paths to violence perpetration began with risk accrual in adolescence, followed by elevated social adversity leading to social exclusion and heightened experiences of violence that effected an alteration of normative social beliefs in adulthood. Males in emerging adulthood with elevated experiences of violence were more likely to report positive attitudes toward the use of violence and delinquency, and, in consequence, perpetrate fighting and bullying behavior. A novel method for computing a cognitive maturity index was developed to quantify the maturation of cognitive control skills where the BIS/BAS failed. Age-related change in cognitive skills and violence risk was best explained by structural-functional changes in brain areas underlying the inhibitory control of reflexive motor actions, risk and reward appraisal, and processing of social signals such as facial affect. Variations in the trajectory of adolescent neurocognitive maturation were found to directly drive the risk for future experiences of violence. Prefrontal cortical and striatal volume, fractional anisotropy, and functional connectivity were revealed to mediate cognitive skills maturity. Pubertal development effected greater neurocognitive maturity in females but delayed neurocognitive maturity in males. A delayed cognitive maturity index led to an increased risk for future experiences of violence. In conclusion, the results support that cognitive skills maturation best informs risk for future adverse outcomes when taken into consideration with sex differences in neurocognitive development and associated sociodemographic influences.