ABSTRACT

Individual variability in diurnal preference or chronotype is commonly assessed with self-report scales such as the widely used morningness–eveningness questionnaire (MEQ). We sought to investigate the MEQ’s internal consistency by applying exploratory factor analysis (EFA) to determine the number of underlying latent factors in four different adult samples, two each from the United Kingdom and Brazil (total N = 3,457). We focused on factors that were apparent in all samples, irrespective of particular sociocultural diversity and geographical characteristics, so as to show a common core reproducible structure across samples. Results showed a three-factor solution with acceptable to good model fit indexes in all studied populations. Twelve of the 19 MEQ items in the three-correlated factor solution loaded onto the same factors across the four samples. This shows that the scale measures three distinguishable, yet correlated constructs: (1) items related to how people feel in the morning, which we termed efficiency of dissipation of sleep pressure (recovery process) (items 1, 3, 4, 5, 7, 9, 13, and 19); (2) items related to how people feel before sleep, which we called sensitivity to buildup of sleep pressure (items 2, 10, and 12); and (3) peak time of cognitive arousal (item 11). Although the third factor was not regarded as consistent since only one item was common among all samples, it might represent subjective amplitude. These results suggested that the latent constructs of the MEQ reflect dissociable homeostatic processes in addition to a less consistent propensity for cognitive arousal at different times of the day. By analyzing answers to MEQ items that compose these latent factors, it may be possible to extract further knowledge of factors that affect morningness–eveningness.

摘要

昼夜偏好或睡眠类型的个体差异通常使用自我报告量表进行评估，例如广泛使用的早晚问卷 (MEQ)。我们试图通过应用探索性因素分析 (EFA) 来确定四个不同成人样本中潜在因素的数量，其中两个来自英国和巴西（总共N= 3,457）。我们专注于所有样本中明显的因素，而不考虑特定的社会文化多样性和地理特征，以显示样本之间的共同核心可重复结构。结果表明，在所有研究人群中，三因素解决方案具有可接受的良好模型拟合指数。三相关因子解决方案中的 19 个 MEQ 项目中有 12 个加载到四个样本的相同因子上。这表明该量表测量了三个可区分但相关的结构：(1) 与人们早上感觉如何相关的项目，我们将其称为睡眠压力消散效率（恢复过程）（项目 1、3、4、5、7 、9、13 和 19)；(2) 与人们睡前感觉有关的项目，我们称之为对睡眠压力累积的敏感性（项目 2、10 和 12）；(3) 认知唤醒的高峰时间（条目 11）。虽然第三个因素不被认为是一致的，因为所有样本中只有一个项目是共同的，但它可能代表主观幅度。这些结果表明，除了在一天中的不同时间不太一致的认知唤醒倾向之外，MEQ 的潜在结构还反映了可分离的稳态过程。通过分析构成这些潜在因素的 MEQ 项目的答案，有可能进一步了解影响早晚的因素。这些结果表明，除了在一天中的不同时间不太一致的认知唤醒倾向之外，MEQ 的潜在结构还反映了可分离的稳态过程。通过分析构成这些潜在因素的 MEQ 项目的答案，有可能进一步了解影响早晚的因素。这些结果表明，除了在一天中的不同时间不太一致的认知唤醒倾向之外，MEQ 的潜在结构还反映了可分离的稳态过程。通过分析构成这些潜在因素的 MEQ 项目的答案，有可能进一步了解影响早晚的因素。