Author's School

Graduate School of Arts & Sciences

Author's Department/Program



English (en)

Date of Award

Summer 8-25-2013

Degree Type


Degree Name

Doctor of Philosophy (PhD)

Chair and Committee

David A Balota


Two powerful methods of improving memory in young and older adults are spacing and testing. The spacing effect refers to the observation that learning material with intervening material between study events, compared to no intervening material between study events, improves long-term memory. The testing effect refers to the finding that retrieving information from memory: via testing) improves memory over merely restudying the information. A combination of the two methods is referred to as spaced retrieval practice, which is the focus of the present dissertation. There were three specific questions addressed. First, how is the function relating continued retrieval practice and long-term memory modulated by the intervening spacing interval: i.e., lag)? Second, how does this function differ between young and healthy older adults given age-related changes in working memory capacity and forgetting rate across short delays? Third, to what extent does the individual's motivation to learn specific information influence the benefit of spaced retrieval practice?

To address the first two questions, Experiment 1 examined the benefit of continued retrieval practice during the acquisition phase on a final cued recall test as a function of lag, retention interval, and age. Participants studied word pairs: e.g., QUEEN - lady) during an initial acquisition phase and were tested on those pairs one, three or five times: e.g., QUEEN - ?????) which were separated by short or long lags: i.e., 1 vs. 3 intervening items). Following either a short or long retention interval, participants completed a final cued recall test. The results revealed that continued testing in the short lag condition led to consistent increases in retention, whereas continued testing in the long lag condition led to increasingly smaller benefits in retention for both age groups. Analysis of final test response latency revealed a different pattern than that observed in accuracy such that young adults benefited from continued testing in the long lag condition but not the short lag condition, and older adults benefited from continued testing in the short lag condition but not the long lag condition.

Experiment 2 extended the first experiment by examining the benefit of massed: testing without intervening material) versus spaced: Lag 4) retrieval practice across age groups. Young adults benefited from continued testing in both the massed and spaced conditions, whereas older adults showed a selective benefit of continued testing in the spaced condition. Again, analysis of response latency on the final test revealed a different pattern of results such that young adults benefited uniquely from continued testing in the spaced condition but not the massed condition, and older adults benefited from continued testing in both conditions.

In pursuit of the third aim regarding the role of participant motivation on the spacing effect, Experiment 3 examined the benefit of retrieval practice for paired associates assigned either a low point value or a high point value. Participants were asked to earn as many points as possible by successfully retrieving items on the final test. Results revealed the predicted benefit of lag and point value on final test accuracy for both young and older adults with no interaction between these two factors. These results suggest that the manipulation of point value effectively modulated participant motivation to learn and retain the paired associates similarly across massed and spaced retrieval conditions.

Emphasis on retention: i.e., conditional final test performance) revealed a pattern of results that diverged from past studies such that young and older adults benefited similarly from spaced retrieval when differences in acquisition performance were minimized: Experiment 1). Moreover, age-related differences in refreshing: Experiment 2) and attention: Experiment 3) were implicated as contributing factors to final test performance above and beyond age differences in acquisition accuracy. Discussion focuses on the role of desirable difficulty in producing the benefits of lag, spacing and testing, along with methodological insights into different measures of memory integrity: response latency and accuracy).


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