van Egmond Lieve T, Meth Elisa M S, Bukhari Shervin, Engström Joachim, Ilemosoglou Maria, Keller Jasmin Annica, Zhou Shiyang, Schiöth Helgi B, Benedict Christian
Department of Surgical Sciences (Sleep Science Laboratory), Uppsala University, Uppsala, Sweden.
Department of Surgical Sciences, Functional Pharmacology, Uppsala University, Uppsala, Sweden.
Nat Sci Sleep. 2022 May 2;14:867-876. doi: 10.2147/NSS.S360433. eCollection 2022.
Acute sleep loss increases the brain's reactivity toward positive and negative affective stimuli. Thus, despite well-known reduced attention due to acute sleep loss, we hypothesized that humans would gaze longer on happy, angry, and fearful faces than neutral faces when sleep-deprived. We also examined if facial expressions are differently perceived after acute sleep loss.
In the present, within-subjects study, 45 young adults participated in one night of total sleep deprivation and one night with an 8-hour sleep opportunity. On the morning after each night, an eye tracker was used to measure participants' time spent fixating images of happy, angry, fearful, and neutral faces. Participants also evaluated faces' attractiveness, trustworthiness, and healthiness on a 100-mm visual analog scale.
Following sleep loss, participants struggled more fixating the faces than after sleep. The decrease in total fixation duration ranged from 6.3% to 10.6% after sleep loss (P<0.001). Contrary to our hypothesis, the reduction in total fixation duration occurred irrespective of the displayed emotion (P=0.235 for sleep*emotion interaction) and was also present for the upper (P<0.001) but not the lower part of the faces (except for the lower part of angry faces). Overall, faces were evaluated as less trustworthy (-2.6 mm) and attractive (-3.6 mm) after sleep loss (p<0.05).
Facial expressions are crucial for social interactions. Thus, spending less time fixating on faces after acute sleep loss may come along with several problems for social interactions, eg, inaccurate and delayed judgment of the emotional state of others. In addition, more negative social impressions of others may lead to social withdrawal in sleep-deprived humans.
急性睡眠剥夺会增强大脑对积极和消极情感刺激的反应性。因此，尽管急性睡眠剥夺会导致注意力显著下降，但我们推测，睡眠不足时，相较于中性面孔，人类会更长时间地注视快乐、愤怒和恐惧的面孔。我们还研究了急性睡眠剥夺后对面部表情的感知是否存在差异。
在本次受试者内研究中，45名年轻成年人参与了一晚的完全睡眠剥夺和一晚有8小时睡眠机会的实验。在每一晚后的早晨，使用眼动仪测量参与者注视快乐、愤怒、恐惧和中性面孔图像的时间。参与者还在100毫米视觉模拟量表上对面孔的吸引力、可信度和健康程度进行评估。
睡眠剥夺后，与睡眠后相比，参与者在注视面孔时更加费力。睡眠剥夺后，总注视持续时间减少了6.3%至10.6%（P<0.001）。与我们的假设相反，总注视持续时间的减少与所显示的情绪无关（睡眠*情绪交互作用的P=0.235），并且在面孔的上部（P<0.001）存在，但在面孔的下部不存在（愤怒面孔的下部除外）。总体而言，睡眠剥夺后，面孔被评为可信度更低（-2.6毫米）和吸引力更低（-3.6毫米）（p<0.05）。
面部表情对于社交互动至关重要。因此，急性睡眠剥夺后花更少的时间注视面孔可能会给社交互动带来一些问题，例如，对他人情绪状态的判断不准确和延迟。此外，对他人更多的负面社会印象可能导致睡眠不足的人出现社交退缩。
