Changes in Subjective Motivation and Effort During Sleep Restriction Moderate Interindividual Differences in Attentional Performance in Healthy Young Men.

Plain-language summary

This study looked at whether changes in how alert, motivated or effortful a man feels explain why some handle sleep loss better than others. Fifteen healthy young men had three nights of 10 hours in bed, five nights of 5 hours, and two recovery nights, with attention tested and alertness, motivation and effort rated every couple of hours. Men who felt less motivated made more impulsive errors on the attention test, and those who felt they were trying harder had more lapses in focus. Men who still felt alert performed worse anyway, so feeling awake did not mean being sharp. A second study in this library, on attention and cognitive performance under the same sleep restriction, reports the other half of this same experiment: the same fifteen men, the same nights, the same laboratory. The two are one study and not two.

Key findings

• Men who felt less motivated during sleep restriction made more impulsive errors (false starts) on attention tests.
• Men who felt they were trying harder during sleep restriction had more lapses in focus.
• Feeling alert did not protect attention during sleep restriction, performance still dropped.