Date of Award

Spring 1-1-2014

Document Type


Degree Name

Doctor of Philosophy (PhD)


Psychology & Neuroscience

First Advisor

Soo H. Rhee

Second Advisor

Marissa A. Ehringer

Third Advisor

Naomi P. Friedman

Fourth Advisor

John K. Hewitt

Fifth Advisor

Vijay Mittal


Self-restraint, or the inhibition of a prepotent response, is a moderately heritable and an important developmental process during toddlerhood, and has been shown to predict executive functions (EFs) and behavioral problems later in life. The aims of the present studies were to (1) gain a better understanding of the etiology of self-restraint in toddlerhood by examining the association between temperament and self-restraint, and (2) gain a better understanding of the development of EFs by examining the association between temperament and self-restraint in toddlerhood and EFs in adolescence.

Participants were twins recruited from the Colorado Longitudinal Twin Study. The present sample included 115 monozygotic (MZ) female twin pairs, 79 dizygotic (DZ) female twin pairs, 106 MZ male twin pairs, and 94 DZ male twin pairs. Temperament, self-restraint, and intellectual abilities were assessed at 14, 20, 24, and 36 months. EFs were assessed at age 17.

Results from Study 1 indicated that higher behavioral inhibition and/or attentional control was associated with better self-restraint, whereas higher negative emotionality predicted lower self-restraint. Results from Study 2 suggest that attentional control is positively associated with Common-EF in boys, consistent with earlier findings that mechanisms of attention are associated with development of EFs. Negative emotionality was negatively associated with Common-EF in boys, and positively associated with Shifting-Specific in boys; however, associations between negative emotionality and EFs were in the opposite direction in girls. Behavioral inhibition was not associated with later EFs.