Does oral breathing disrupt memory consolidation during waking rest? A registered report

Studies of waking rest, whereby passive rest is compared with an active task, have shown a benefit for declarative memory during short waking rest periods, which has been argued to result from the active task disrupting slow oscillations that occur during rest. Arshamian et al. (2018) found that nasal breathing while resting for an hour led to an advantage for olfactory memory consolidation compared with oral breathing, which has also been argued to result from the disruption of slow oscillations during oral breathing. In the present pre-registered research, we looked to see whether this oral breathing disruption extended to impair declarative memory consolidation, and if it is modulated by the presence of an active task. We used a 2 × 2 within-participants counterbalanced design of two sessions separated by a week where participants breathed either orally (induced by a nose clip) or nasally (induced through tape over the mouth). Each session involved learning two sets of pseudowords followed by either waking rest or an active task (N-back) for 15 min during the breathing manipulation. Memory performance was assessed by a recognition task. Our results show that the nasal advantage did not generalise to pseudowords, nor were we able to replicate the waking rest advantage or show an interaction between these factors. This study contributes to a growing body of evidence that challenges the consistency of the waking rest advantage and highlights the need for further exploration of the influence of breathing pathway on memory processes.