Award Date


Degree Type


Degree Name

Doctor of Philosophy (PhD)



First Committee Member

Colleen M. Parks

Second Committee Member

Mark Ashcraft

Third Committee Member

Joel Snyder

Fourth Committee Member

CarolAnne Kardash

Number of Pages



Research on forgetting irrelevant information in working memory (WM) has supported two

conflicting theories, inhibition (Oberauer & Lewndowsky, 2016) and decay (Dagry et al., 2017;

Dagry & Barrouillet, 2017). However, these conflicting results may be due to the fact that different methods were used to assess each model. In Experiment 1, we combined those methods to create a modified distractor span task that allows for a direct comparison of the models. Participants processed words that were to be remembered (targets) and others that were to be forgotten (distractors); the amount of free time after each distractor varied, with total trial time held constant across conditions. There were more distractor intrusions on a working memory reconstruction task when less free time was available, supporting an inhibition model. However, this free time difference disappeared on a long-term memory recognition task, which could support either model. In Experiment 2, we tested whether there were individual differences in the modified distractor span task. Individual differences typically arise in active control but not passive processes; therefore, they can be used to adjudicate between the models. We found low WM participants, as compared to high WM, mistakenly remembered more distractors when given less free time. This suggests that forgetting distractors may be an active process that is sensitive to the amount of time available to inhibit, in line with the SOB-CS model. Therefore, inhibition, as proposed by the SOB-CS model, best accounts for forgetting in working memory but the ramifications of that inhibition for long-term memory remains inconclusive.


decay; distractors; forgetting; inhibition; working memory



File Format


File Size

0.58 MB

Degree Grantor

University of Nevada, Las Vegas




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