Degree Date



Doctor of Philosophy (PhD)




Younger and older adults have displayed differing biases for positive and negative material in previous research. The overwhelming majority of this valence effect research, however, has focused on singular tasks within the cognitive domains of attention, memory, and perception separately, and has not explored the cross-task, cross-domain robustness or stability of these effects. The present study sought to address this gap in the literature by investigating younger and older adults’ cognitive valence biases, factors that might be used as predictors of such biases, and the stability of these biases across cognitive domains. Results revealed no significant differences in the bias patterns for valenced material (positive and negative) when comparing the younger and older adult samples’ scores on nine cognitive tasks. Furthermore, none of the proposed predictor variables were consistently correlated with participants’ bias for positive or negative material, and task bias scores (positive or negative) were not stable within or across the cognitive domains. A discussion of these outcomes as well as their implications for the valence effect literature is provided.


The results from this dissertation are published in Dever, Lindsay, and Djordje Milićević. “Ambient Prime Geodesic Theorems on Hyperbolic 3-Manifolds.” International Mathematics Research Notices, Oct. 2021,