Reductions in Retrieval Competition Predict the Benefit of Repeated Testing

Rafidi, Nicole S; Hulbert, Justin C; Brooks, Paula P; Norman, Kenneth A
Issue date: 2018
Creative Commons Attribution 4.0 International (CC BY)
Cite as:
Rafidi, Nicole S, Hulbert, Justin C, Brooks, Paula P, & Norman, Kenneth A. (2018). Reductions in Retrieval Competition Predict the Benefit of Repeated Testing [Data set]. Princeton University.
  author      = {Rafidi, Nicole S and
                Hulbert, Justin C and
                Brooks, Paula P and
                Norman, Kenneth A},
  title       = {{Reductions in Retrieval Competition Pred
                ict the Benefit of Repeated Testing}},
  publisher   = {{Princeton University}},
  year        = 2018,
  url         = {}

Repeated testing (as opposed to repeated study) leads to improved long-term memory retention, but the mechanism underlying this improvement remains controversial. In this work, we test the hypothesis that retrieval practice benefits subsequent recall by reducing competition from related memories. This hypothesis implies that the degree of reduction in competition between retrieval practice attempts should predict subsequent memory for the practiced items. To test this prediction, we collected electroencephalography (EEG) data across two sessions. In the first session, participants practiced selectively retrieving exemplars from superordinate semantic categories (high competition), as well as retrieving the names of the superordinate categories from exemplars (low competition). In the second session, participants repeatedly studied and were then tested on Swahili-English vocabulary. One week after session two, participants were again tested on the vocabulary. We trained a within-subject classifier on the data from session one to distinguish high and low competition states. We then used this classifier to measure competition across multiple retrieval practice attempts in the second session. The degree to which competition decreased for a given vocabulary word predicted whether that item was subsequently remembered in the third session. These results are consistent with the hypothesis that repeated testing improves retention by reducing competition. Experiment consisted of 3 sessions: 1 of EEG recording, 1 of EEG and behavior recording in the form of written responses, and 1 of behavior recoding in the form of written responses. 48 subjects participated in the initial EEG recording session, 40 participated in all three sessions. Download the README.txt file for a detailed description of this dataset's content.

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