High-Intensity Acute Exercise and Directed Forgetting on Memory Function

Abstract

Background and Objectives: Despite accumulating research demonstrating that acute exercise may enhance memory function, very little research has evaluated whether acute exercise can effectuate intentional directed forgetting (DF), an adaptative strategy to facilitate subsequent memory performance. Materials and Methods: A three-arm parallel-group randomized controlled intervention was employed. Participants were randomized into one of three groups, including: (1) exercise plus DF (Ex + DF), (2) DF (directed forgetting) only (DF) and (3) R (remember) only (R). The acute bout of exercise included 15 min of high-intensity treadmill exercise. The memory assessment involved the presentation of two-word lists. After encoding the first word list, participants were either instructed to forget all of those words (DF) or to remember them. Following this, participants encoded the second word list. Results: We observed a statistically significant main effect for list F(1, 57) = 12.27, p < 0.001, η2p = 0.18, but no main effect for group F(2, 57) = 1.32, p = 0.27, η2p = 0.04, or list by group interaction, F(2, 57) = 2.89, p = 0.06, η2p = 0.09. Conclusion: This study demonstrates a directed forgetting effect in that cueing an individual to forget a previously encoded list of items facilitates memory performance on a subsequent list of items. However, we failed to demonstrate any beneficial effect of acute exercise in facilitating directed forgetting. These findings are discussed in the context of directed forgetting theories, particularly the attention inhibition mechanism, as well as the timing of the acute bout of exercise.

Effects of acute exercise on directed forgetting

“…As a follow-up to our first experiment, in our second experiment, instead of focusing on selective forgetting, we specifically evaluated whether acute exercise could augment the beneficial effects of direct forgetting on List 2. 7 In these two experiments, we demonstrated a directed forgetting benefit (List 2 enhancement effect) but failed to demonstrate any ability for acute exercise to augment this directed forgetting effect. In our past two experimental studies on this topic, acute exercise occurred shortly before encoding List 1.…”

“…As we have discussed elsewhere, 7 various theoretical accounts for DF have been suggested, which include selective rehearsal, active erasure, and tagging and selective search. Within the context of exercise, the inhibitory account of DF may be a contributor to any potential exercise-related effect on DF.…”

“…The total sample included 97 participants, which is considerably higher than other related research on this subject matter (N = 60). 7 This was based on an a-priori power analysis indicating that at least 93 participants would be needed for the following inputs, α = 0.05, power = 0.85, 3 groups, 2 within-subject measurements, and a partial η2 of 0.03. Participants (18-26 years), including undergraduate and graduate students, were recruited via convenience sampling.…”

“…The directed forgetting paradigm employed for this experiment was identical to our past research. 7 In brief, this involved two lists (List 1 and List 2; L1 and L2), with each list comprised of 16 unrelated words from the Toronto Word Pool. Words were presented in a set random order, displayed individually at a rate of 4-seconds followed by a 1-second interstimulus interval.…”

“…After L1 presentation, and depending on group assignment, participants received specific instructions. As detailed elsewhere, 7 those in the DF group were told to forget the words from L1, whereas those in the R group were told to remember all the L1 words.…”