Social behavior is altered in mice one day following chronic sleep restriction. (A) Sociability test: time spent in the chamber measured at one day following completion of chronic sleep-restriction (pre-recovery) shows a statistically significant Condition × Chamber interaction and a simple effect of chamber. Sleep-restricted mice regardless of sex spent more time in the chamber with the stranger mouse than did control mice. (B) Sociability test: sniffing time measured one day following chronic sleep-restriction (pre-recovery) reveals a statistically significant Condition × Chamber interaction. Main effects of condition and chamber were also statistically significant. Sleep-restricted mice had increased sociability compared to control mice one day following chronic sleep-restriction (pre-recovery). (C) Social novelty test: time spent in the chamber one day following chronic sleep restriction (pre-recovery) shows a statistically significant main effect of chamber that does not change depending on condition. (D) Social novelty test: sniffing time measured one day following chronic sleep-restriction (pre-recovery) reveals a statistically significant main effect of chamber and a near statistically significant main effect of sex, but no statistically significant effect of condition. Bars represent the means ± SEMs in (A&C) 11 control male, 13 sleep-restricted male, 22 control female, and 17 sleep-restricted female mice, and in (B&D) 10 control male, 13 sleep-restricted male, 21 control female, and 17 sleep-restricted female mice.