Notes on:

Stepan, M. E., Altmann, E. M., & Fenn, K. M. (2021): Caffeine selectively mitigates cognitive deficits caused by sleep deprivation

1 What?

Examine the impact of caffein on two types of tasks that are impaired by sleep deprivation:

• unravel placekeeping (Altmann, Trafton, and Hambrick 2014): difficult tasks with interuptions
• Press a button as soon as the light appear: simple, sustain-attention, reaction-timed tasks (pvt)

2 Why?

Sleep deprivation impairs a wide range of cognitive processes, but the precise mechanism underlying these deficits is unclear. Modern psychology suggests that sleep deprivation mainly impair the ability to focus over a long time (vigilant attention).

3 How?

276 people were assigned to placekeeping (unravel) or a psychomotor vigilance task (pvt). Then they are randomly assigned to either stay awake the following night or go home. The next day, all participant consumed 200mg of caffein or placebo. After an absorption period, all participants completed unravel and pvt again.

4 And?

Caffeine counteracted this impairment in vigilant attention but did not significantly affect placekeeping for most participants, though it did reduce the number of sleep-deprived participants who failed to maintain criterion accuracy.

Simply put: caffein may improve the ability to stay awake and attend to simple tasks, but doesn’t help with complex tasks.

5 References