Author ORCID Identifier

Year of Publication


Degree Name

Doctor of Philosophy (PhD)

Document Type

Doctoral Dissertation


Arts and Sciences



First Advisor

Dr. Ramesh S. Bhatt


Infants’ ability to channel their cognitive resources by controlling their visual attention allows them to be active agents in their learning and development. Individual differences in attentional control have been linked to a wide variety of developmental outcomes including disparities between social classes in cognitive functioning. However, it is yet unknown when in development differences in attentional control related to sociodemographic factors emerge, or how factors of the home environment and the infant’s stress response relate to this effect. Accordingly, Experiment 1 examined whether certain sociodemographic factors, such as socioeconomic and minority status, predict 3.5-month-old infants’ (N = 102) ability to control their attention, as indexed by their average fixation durations. The results of this study not only suggest that average fixation duration is a viable metric for studying individual differences in cognitive development early in life, but are also, to my knowledge, the first demonstration of associations between sociodemographic risk and attentional control as early as 3.5 months of age. Next, in Experiment 2, an additional sample of 3.5-month-olds (N = 96) was recruited to determine the roles of home stability (i.e., home chaos and adherence to routines) and infant’s physiological response to stress (i.e., cortisol) in the relationship between attentional control and sociodemographic factors. A sub-sample of these infants were tested again at 5 months of age (N = 60) to examine changes over time in the relationship between sociodemographic risk, cortisol, and home stability. Two theoretical models were tested, the first being that instability in the home and maladaptive child rearing practices cause dysregulation of infants’ stress responses (indexed by heightened basal cortisol levels), which, in turn, disrupts their attentional control abilities. No empirical support for this model was found. The second model tested assumed that attentional control serves as a protective factor such that infants with more robust attentional control abilities show a less pronounced association between instability in the home and cortisol levels. Support for this model was found whereby only infants with poorer attentional control, indexed via average fixation durations, showed elevated cortisol levels in the context of poorer adherence to routines. The results of this project indicate that associations between attentional control and sociodemographic factors emerge very early in life. Therefore, intervention efforts aiming to reduce the gap in developmental outcomes between minority and low-SES infants and children and their peers may be beneficial beginning in early infancy. Furthermore, attentional control may be useful as a screening tool to determine which infants may be more susceptible to adverse home environments, and training attentional control may be one pathway to promote resilience early in life.

Digital Object Identifier (DOI)

Funding Information

This work was supported by an American Psychological Association Dissertation Research Award (December 2018 to May 2020), a Ruth L. Kirschstein Research Service Award Predoctoral Fellowship (1F31HD096790-01A1; February 2019 to July 2020), and a grant from the National Institute of Child Health and Human Development (HD075829; April 2015 to July 2020).