Date of Award

Spring 1-1-2015

Document Type


Degree Name

Doctor of Philosophy (PhD)


Psychology & Neuroscience

First Advisor

Tim Curran

Second Advisor

Alice F. Healy

Third Advisor

Albert Kim

Fourth Advisor

Leaf Van Boven

Fifth Advisor

Michael C. Mozer


The spacing effect shows that studying information at distributed intervals leads to better long-term memory than massing study episodes together over the same cumulative amount of time. Prior research has not made explicit predictions about neural activity in the EEG domain that should occur at different study repetition lags under different spacing effect theories. One main purpose of this thesis is to make these predictions in terms of the neural activity expected under different spacing effect hypotheses, whereas another is to test these predictions. Knowledge about neural patterns underlying the spacing effect can shed light on why this effect occurs, which would support or challenge the hypotheses presented here as well as possibly provide a physiological grounding when considering the spacing effect in educational settings. We used event-related potentials and time–frequency methods to analyze spaced and massed study repetitions, as well as measures of neural similarity across presentations to inform these predictions. To summarize our findings, when studying information for a second time at a spaced interval, the retrieval of the initial study episode from long-term memory and the additional semantic processing received benefits performance on a subsequent test compared to studying massed repetitions.