SOCIAL DESIRABILITY MEDIATES SELF-REPORTED SLEEPINESS DURING A LABORATORY TOTAL SLEEP DEPRIVATION STUDY

Abstract Introduction Total sleep deprivation (TSD) increases sleepiness and impairs vigilant attention. There are large individual differences in vulnerability to sleep loss, but individuals’ self-ratings of sleepiness often do not align with their objective performance impairment. Here we investigated whether the trait of social desirability – the desire to conform to social standards – plays a role. Methods N=39 healthy adults (ages 27.6±4.6y; 22 men) completed a 3-night/4-day in-laboratory study with 10h baseline and recovery sleep opportunities (22:00–08:00) preceding and following a 38h period of TSD. Every 2–4h during TSD, subjects completed the Karolinska Sleepiness Scale (KSS) and a 10min Psychomotor Vigilance Test (PVT) to assess subjective sleepiness and vigilant attention, respectively. Throughout the study, subjects were behaviorally monitored by the researchers. Prior to the study, subjects completed the Marlow-Crowne Social Desirability (MCSD) scale. Based on standard criteria, subjects were categorized post hoc into average (n=13) and high (n=26) social desirability groups (no subjects in the sample scored low on social desirability). Self-reported sleepiness scored on the KSS and lapses (reaction times ≥500ms) on the PVT were analyzed using mixed-effects ANOVA with fixed effects for time awake and MCSD group and their interaction. Results As expected, there was a main effect of time awake for KSS score (F[12,441]=31.48, p<0.001) and PVT lapses (F[12,441]=16.27, p<0.001), with sleepiness and lapses increasing during TSD. We found a main effect of MCSD group for KSS score (F[1,441]=4.56, p=0.033), with the high MCSD group reporting lower levels of sleepiness than the average MCSD group. However, there was no effect of MCSD group for PVT lapses (p=0.93) and no time awake by MCSD interaction for either KSS (p=0.86) or PVT (p=0.99). Conclusion Subjects high in social desirability reported less sleepiness during TSD than those with average social desirability yet their objective performance was equally degraded. This finding has implications for fatigue risk management because individuals with high social desirability may underreport their sleepiness. This may undermine the reliability of self-report assessments of sleepiness and ability to work safely. [ 1] Whether there is bias in self-reported sleepiness for individuals low in social desirability as well remains to be investigated. Support (If Any) Support: ONR N00014-13-1-0302 and PRMRP W81XWH-20-1-0442