The effects of partial sleep deprivation on mind wandering, executive performance and affect

Insufficient sleep is a common occurrence in modern society and has severe consequences for our attention, executive functioning (EF), and affect. Mind wandering (MW) is a phenomenon where attention shifts from an external task to internal thoughts. These shifts can take on different characteristics, such as relating to specific mental content or not (mind blanking, MB), and can be engaged deliberately (D-MW) or spontaneously (S-MW). MW is related to impaired EF and worsened emotional states, yet it is unclear how these associations are influenced by sleep loss. We recruited 34 healthy adults to a partial sleep deprivation (PSD) protocol, where they slept on average 1.7 h less, compared to a period of normal sleep (NS), for 3 consecutive nights. Participants engaged in the finger-tapping random sequence generation task that provided two objective measures of EF performance, the variability in the responses and the entropy of the generated sequences. We assessed participants' momentary affect before and after the task, while subjective reports of attentional states (on-task, MW, MB, and S/D-MW) were assessed during the task. Results indicated that greater sleep loss resulted in more MW, MB, behavioural variability and negative affect, and reduced positive affect. Furthermore, MW episodes were preceded by reduced EF performance only following the PSD, but not after NS. Finally, we found that pre-task positive affect may ameliorate the unfavourable effects of sleep loss on objective and subjective measures of MW. These findings highlight the importance of sufficient sleep in maintaining sustained attention, optimal task performance, and good mood.