Interindividual differences in attentional vulnerability moderate cognitive performance during sleep restriction and subsequent recovery in healthy young men.

Plain-language summary

This study asked whether a man's tendency to zone out after short sleep predicts whether his working memory and spatial skill keep improving with practice. Fifteen healthy young men slept three normal nights, then five nights of five hours in bed, then two recovery nights. While awake they were tested about every two hours. The attention test was simple. A number appears. Tap as fast as you can. The paper defines a lapse as a reaction time of half a second or longer, a brief blank. For each man they counted how much those blanks rose from his last well-rested day to his last short-sleep day. That rise was his vulnerability score. They did not split the men into two named groups. They treated the score as a sliding scale and looked at the predicted memory and spatial curves at the low end of the scale against the high end. At the low end, where lapses barely rose, working memory and spatial processing kept getting better across the study. At the high end, where lapses rose a lot, they did not. Practice went on for everyone. In the men most sensitive to short sleep it did not show up as improvement. A second study in this library, on motivation and effort under the same sleep schedule, is the other half of the same experiment: same fifteen men, same nights, same lab.

Key findings

• Men whose blank-outs rose least after five short nights kept improving on working memory and spatial tasks.
• Men whose blank-outs rose most did not.
• Vulnerability was each man's own change in lapses, not a preset type. The comparison was the low end against the high end of that range.