Neural oscillations are known to underlie the dynamic neural processes related to episodic memory. On the one hand, low-frequency delta waves have been seen to facilitate memory consolidation,...Show moreNeural oscillations are known to underlie the dynamic neural processes related to episodic memory. On the one hand, low-frequency delta waves have been seen to facilitate memory consolidation, while higher frequency alpha waves are associated with more engagement in autobiographical thinking (ABT) which interrupts consolidation. Neural oscillations can be modulated via rhythmic auditory stimulation, also known as binaural beats (BB). Several studies have found that BBs have potential for enhancing cognitive functioning, such as attention and working memory. However, little is known about the efficacy of BB entrainment with regard to episodic memory. In this study, we investigated the effects of listening to alpha (9Hz) and delta (0.5 Hz) BB on episodic memory performance in an old/new recognition task in a within-subjects design. Thirty-six participants underwent three rounds of encoding, each followed by an 8-minute delay during which they listened to either alpha, delta or control BB soundtrack, ending with a recognition test. During BB stimulation, participants also reported the frequency and intensity of ABT. Results showed that listening to alpha and delta BBs did not significantly alter subsequent memory performance, nor did it affect ABT. Additionally, no correlations were found between ABT and memory scores. We discuss limitations to our methods and offer ideas for future research.Show less
Recent studies showed that performing a 2-Back during post-encoding had similar facilitating effects on memory consolidation as wakeful rest, possibly due to a balance between the interreference...Show moreRecent studies showed that performing a 2-Back during post-encoding had similar facilitating effects on memory consolidation as wakeful rest, possibly due to a balance between the interreference effects of autobiographical thinking (suppressed during 2-Back) and the facilitating effects of offline replay (increased during rest) on memory consolidation. The current study investigates the relationship between autobiographical thinking and memory consolidation in a within-subjects design, by comparing two post-encoding periods differing in task difficulty: 0-Back and 2-Back. Participants (N = 22) performed two sessions of three blocks; an encoding task, a 15-minute post-encoding period, and a recognition task. Autobiographical thinking was measured via experience-sampling thought probes. We predicted autobiographical thinking to interfere with consolidation and more autobiographical thinking during the 0-Back compared to the 2-Back. We also expected equal memory consolidation across conditions, assuming increased offline replay during the 0-Back. As hypothesized, autobiographical thinking was higher during the 0-Back than during the 2-Back, and results showed no difference in memory consolidation across the post-encoding conditions. The present findings did not show a direct relationship between autobiographical thinking during post-encoding and consolidation. We argue that the failure to detect a relationship can be explained by the current study being underpowered, due to small sample size and the number of thought probes. In conclusion, results do show that manipulating task difficulty of the n-Back can be an effective method to affect autobiographical thinking. However, the relationship of autobiographical thinking and memory consolidation remains unclear, and requires further research.Show less
Previous research has shown that a post-encoding rest period has similar effects on ongoing memory consolidation as executing a 2-back task, due to a suspected balance between interference...Show morePrevious research has shown that a post-encoding rest period has similar effects on ongoing memory consolidation as executing a 2-back task, due to a suspected balance between interference suppression (in 2-back) and spontaneous reactivation of memory traces (in rest). The current study investigates the relationship between post-encoding task difficulty, autobiographical thinking and episodic memory consolidation by improving methodological issues in previous work. Episodic memory consolidation in a 2-back condition is compared to a 0-back condition, while analyzing autobiographical thinking proportions. It is expected that autobiographical thinking negatively correlates with consolidation and that autobiographical thinking is higher in the 0-back condition, compared to 2-back. However, given the higher chance of spontaneous reactivation of memory traces in the 0-back condition, it is expected that both conditions show equal memory consolidation. In a within-subjects design, participants (N = 22) are shown face stimuli, which they later identify in a recognition test, after executing a 0-back or 2-back task. During these n-back tasks, thought probes are presented targeting autobiographical thinking (and other mindwandering instances). Results show no direct relationship between autobiographical thinking and memory consolidation, but previous studies are replicated by showing similar memory consolidation after performing the two n-back tasks. In conclusion, the results reinvigorate the idea of a post-encoding 2-back task resulting in similar consolidation outcomes as a less demanding post-encoding task. Moreover, the outcomes suggest that n-back task difficulty affects autobiographical thinking, but the direct effect of this process on memory consolidation requires further investigation, potentially in the form of a neuroimaging study.Show less
