Researchers asked 173 young adults to complete Cognitive Bias Modification (CBM) training in either the morning or evening. CBM is aimed at changing biases in a person’s thought processes, such as a tendency to label ambiguous facial expressions as negative rather than positive. Negative cognitive biases could contribute to depression and being a night owl is also a risk factor for the condition.
Chronotype refers to when someone is likely to naturally fall asleep and wake up. Most people describe this as being either an early bird or a night owl. The study team found moderate evidence to suggest that participants learnt better when they were able to complete their CBM session at a time that suited their chronotype (evening for night owls, morning for early birds).
The study team also found that this may be particularly important for night owls who were less able to adapt to non-optimal times-of-day, possibly because they experience more social jetlag. Social jetlag is a misalignment between when a person is likely to be most awake and when society might expect them to be most active.
Paper: Crisp C et al. (2024). Chronotype and emotion processing: a pilot study testing timing of online cognitive bias modification training. BMJ Mental Health.