Graduate Studies

 

First Advisor

Timothy D. Nelson

Degree Name

Doctor of Philosophy (Ph.D.)

Department

Psychology

Date of this Version

8-2024

Document Type

Dissertation

Citation

A dissertation presented to the faculty of the Graduate College of the University of Nebraska in partial fulfillment of requirements for the degree of Doctor of Philosophy

Major: Psychology

Under the supervision of Professor Timothy D. Nelson

Lincoln, Nebraska, August 2024

Comments

Copyright 2024, Marla Lopez. Used by permission

Abstract

Research has identified executive control (EC) as an important predictor of dietary outcomes among youth. Executive control in preschool age has been shown to predict important outcomes across development for youth, indicating that good, foundational EC abilities are associated with successful development in later life. Dietary outcomes across adolescence, an important transitional period for establishing healthy eating behaviors, are understudied. Therefore, the current study sought to link two critical developmental periods, examining how preschool EC is associated with dietary trajectories across adolescence. Further, the study aimed to identify how contextual factors, specifically indices of socio-economic status and the home and neighborhood food environment, moderated this association. In a longitudinal study including 326 participants, results showed that on average, dietary outcomes as measured by the Healthy Eating Index (HEI) across ages 14 to 18 followed a relatively stable trajectory. Further, of the contextual moderators examined, income-to-needs ratio and counts of convenience stores present in the neighborhood moderated the association between preschool EC and adolescent dietary outcomes. Contrary to hypotheses, these interactions occurred at lower levels of obesogenic risk (e.g., approximately average and higher income-to-needs ratio; approximately two and less convenience store counts). In these models, at lower levels of obesogenic risk, preschool EC was positively associated with the intercept factor at age 14, indicating that better preschool EC was associated with better HEI scores in early adolescence. In the income-to-needs ratio model, preschool EC was negatively associated with the slope, indicating that while financial resources were initially beneficial for adolescents with better preschool EC at age 14, this effect dissipated over time. Conversely, adolescents with poorer preschool EC experienced improvement in dietary outcomes over time. Findings point to the longitudinal impact preschool EC has on dietary outcomes, and the conditions under which such associations unfold.

Advisor: Timothy D. Nelson

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