The impact of one night of sleep deprivation on moral judgments

Moral decision-making at night and the impact of night work with blue-enriched white light or warm white light: a counterbalanced crossover study

BACKGROUND

Cognitive function, including moral decision-making abilities, can be impaired by sleep loss. Blue-enriched light interventions have been shown to ameliorate cognitive impairment during night work. This study investigated whether the quality of moral decision-making during simulated night work differed for night work in blue-enriched white light, compared to warm white light.

METHODS

Using a counterbalanced crossover design, three consecutive night shifts were performed in blue-enriched white light (7000 K) and warm white light (2500 K) provided by ceiling-mounted LED luminaires (photopic illuminance: ∼200 lx). At 03:30 h on the second shift (i.e. twice) and at daytime (rested), the Defining Issues Test-2, assessing the activation of cognitive schemas depicting different levels of cognitive moral development, was administered. Data from 30 (10 males, average age 23.3 ± 2.9 years) participants were analysed using linear mixed-effects models.

RESULTS

Activation of the post-conventional schema (P-score), that is, the most mature moral level, was significantly lower for night work in warm white light (EMM; estimated marginal mean = 44.3, 95% CI = 38.9-49.6; pholm=.007), but not blue-enriched white light (EMM = 47.5, 95% CI = 42.2-52.8), compared to daytime (EMM = 51.2, 95% CI = 45.9-56.5). Also, the P-score was reduced for night work overall (EMM = 45.9, 95% CI = 41.1-50.8; p=.008), that is, irrespective of light condition, compared to daytime. Neither activation of the maintaining norms schema (MN-score), that is, moderately developed moral level, nor activation of the personal interest schema (i.e. the lowest moral level) differed significantly between light conditions. The MN-score was however increased for night work overall (EMM = 26.8, 95% CI = 23.1-30.5; p=.033) compared to daytime (EMM = 23.1, 95% CI = 18.9-27.2).

CONCLUSION

The results indicate that moral decisions during simulated night work in warm white light, but not blue-enriched white light, become less mature and principle-oriented, and more rule-based compared to daytime, hence blue-enriched white light may function as a moderator. Further studies are needed, and the findings should be tentatively considered.Trial registration: ClinicalTrials.gov (ID: NCT03203538) Registered: 26/06/2017; https://clinicaltrials.gov/study/NCT03203538.

Association of sleep with moral severity to accidental harm transgressions: A cross-sectional study

Based on the assumptions that moral judgement activities require cognitive control, a capacity impaired by low sleep quality or a lack of sleep, several studies have explored the association between sleep and moral judgements. However, even if some studies support the association between sleep and both moral awareness and unethical behaviours, others failed to find a robust association between sleep and moral utilitarianism. In the present well-powered preregistered cross-sectional study, we explored the role of sleep in another class of moral judgement, namely third-party punishment (in which people have to assess the morality of an agent who transgressed a moral rule). Specifically, we targeted the association of sleep with judgements of accidental harm transgressions, which are assumed to be especially cognitively costly. Our main analysis showed no association of overall sleep quality during the past month with moral severity in these transgressions. This result was confirmed for other sleep indexes (sleep quantity in the past month, and sleep quantity and quality in the past night). Lastly, we exhaustively explored the associations of all sleep indexes with all classes of moral judgement (accidental, intentional, attempted transgressions and control scenarios). These additional results revealed associations between sleep and moral severity, but none survived correction for multiple testing. Equivalence tests confirmed that the effect sizes of all these associations were relatively low (|r < 0.25|). We ensured that the lack of robust association between natural sleep and third-party punishment could not be explained by a low quality of the data collected.

Which Dark Personality Traits Could Predict Insomnia? The Mediated Effects of Perceived Stress and Ethical Judgments

This study aimed to investigate the relationship between dark personality traits and insomnia by considering the mediated effects of perceived stress and ethical judgments. This descriptive and correlational study was conducted with 464 university athlete students from individual and team sports. Dark Triad Scale (DTS), Insomnia Severity Index (ISI), Perceived Stress Scale (PSS), and Moral Content Judgment in Sport Questionnaire (MCJSQ) were used. Significant correlation coefficients were observed between the dark personality traits and other variables. Regression analysis showed that psychopathy (about 19%) and ethical judgments (about 16%) could predict insomnia. It was shown that among dark personality traits, psychopathy along with ethical judgments could predict insomnia.

Research on the Impact of Regular Exercise Behavior of College Students on Academic Stress and Sleep Quality during the COVID-19 Pandemic

When college students face the COVID-19 pandemic and new learning challenges simultaneously, how to reduce or alleviate their own academic stress has become a topic of concern to students and their parents. The psychological and physiological benefits of regular exercise have been confirmed by related studies. This study aimed to explore the impact of college students' regular exercise behavior on academic stress and sleep quality during the COVID-19 pandemic. This study used a purposive sampling method to collect data through online questionnaires posted to relevant college student groups in northern, central, southern, and eastern Taiwan and the outlying islands. A total of 320 questionnaires were collected, with a response rate of 91.4%; based on 304 valid questionnaires. The validity rate was 95%. The obtained data were entered in SPSS 24.0 statistical software, and the correlation between variables was analyzed with AMOS 24.0 statistical software. The results show that hypothesis 1 is established, that is, regular exercise behavior of college students during the COVID-19 pandemic has a significant negative impact on academic stress, meaning that during the COVID-19 pandemic, if college students can use their spare time to make exercise part of their life, such a regular schedule will help reduce their academic stress. In addition, the empirical results show that hypothesis 2 is established, that is, regular exercise behavior of college students during the COVID-19 pandemic has a significant positive impact on sleep quality. A possible reason is that under the COVID-19 pandemic, the efficiency of the body to absorb oxygen is increased through regular exercise, which reduces pressure and improves sleep quality. Hypothesis 3 is also confirmed, that is, the academic stress of college students during the COVID-19 pandemic has a significant negative impact on sleep quality. The reason may be that many leisure and social activities have been suspended during the COVID-19 pandemic, and thus college students exercised and studied during the time they originally intended for leisure and social activities, which reduced their academic stress, stabilized their mood, and improved their sleep quality.

How Stable are Moral Judgments?

Psychologists and philosophers often work hand in hand to investigate many aspects of moral cognition. In this paper, we want to highlight one aspect that to date has been relatively neglected: the stability of moral judgment over time. After explaining why philosophers and psychologists should consider stability and then surveying previous research, we will present the results of an original three-wave longitudinal study. We asked participants to make judgments about the same acts in a series of sacrificial dilemmas three times, 6-8 days apart. In addition to investigating the stability of our participants' ratings over time, we also explored some potential explanations for instability. To end, we will discuss these and other potential psychological sources of moral stability (or instability) and highlight possible philosophical implications of our findings.

Sleeping over moral dilemmas modulates utilitarian decision-making

Moral decision-making depends on the interaction between emotional and cognitive control processes, which are also affected by sleep. Here we aimed to assess the potential role of sleep in the modulation of moral decisions over time by testing the change in behavioral responses to moral dilemmas over time (1 week). Thirty-five young adults were tested twice, with one week between the sessions. In each session, participants were presented with 24 sacrificial (12 Footbridge- and 12 Trolley-type) and 6 everyday-type moral dilemmas. In sacrificial dilemmas, participants had to choose whether or not to kill one person to save more people (utilitarian choice), to judge how morally acceptable the proposed solution was, and how they felt in terms of valence and arousal during the decision. In everyday-type dilemmas, they had to decide whether to pursuit moral violations involving dishonest behavior. Between the sessions, the participants’ sleep pattern was assessed via actigraphy. We observed that participants reduced the utilitarian choices in the second session, and this effect was more pronounced for the Trolley-type dilemmas. We also showed that after a week participants judged the utilitarian choices as less morally acceptable, but there was no change in self-reported emotional reactivity (i.e., valence, and arousal). Moreover, sleep efficiency was mildly negatively associated with the changes in decision choices and moral acceptability for the Footbridge-type dilemmas. Taken together, our data suggest that dealing with a moral situation engages several interacting factors that seem to go beyond the competing roles of cognitive and emotional processes.

Association of natural sleep with moral utilitarianism: No evidence from 6 preregistered studies

Recent research has shown that sleep is associated with moral judgment. Most of these studies have focused on moral awareness and unethical behaviors but far fewer have examined the impact of sleep on moral utilitarianism. We report a set of six preregistered cross-sectional studies which explore the association between moral utilitarianism and sleep quantity and quality at both the acute and chronic levels. A total of 582 participants drawn from diverse populations (USA, UK and France) addressed various measures of sleep quantity, sleep quality, and moral utilitarianism. We report a meta-analysis which showed only a weak association between sleep and moral utilitarianism. Despite the heterogeneity in the samples and methods employed, equivalence tests ruled out the possibility that we missed medium to strong effect sizes. We discuss the implication of these findings in the light of the moral judgment literature.

Sleep deprivation undermines the link between identity and intergroup bias

This research seeks to bridge two findings-on the one hand, top-down controlled processes inhibit display of intergroup bias; on the other one hand, sleep deprivation impairs cognitive control processes. Connecting these two proven statements, begs the question: would sleep deprivation also influence intergroup bias? This intriguing link has hardly been explored in extant literature. To fill this gap, we theorize through the lens of social identity. Previous research has shown that individuals who share a common identity with an outgroup are more motivated to inhibit biases toward the outgroup than do their counterparts who do not endorse such common identity. We predicted that this motivated inhibition would be compromised by sleep deprivation. Across two studies, as predicted, we found that only when an individual has adequate sleep did common ingroup identity attenuate the display of intergroup bias, whereas individuals with short habitual sleep (study 1) or after one-night sleep deprivation (study 2) displayed equally high levels of intergroup bias regardless of their high or low levels of common ingroup identity. In the global context of incessant intergroup bias and diminishing sleep time, our findings offer new insights for understanding and handling intergroup bias.

Daytime REM sleep affects emotional experience but not decision choices in moral dilemmas

Moral decision-making depends on the interaction between automatic emotional responses and rational cognitive control. A natural emotional regulator state seems to be sleep, in particular rapid eye movement (REM) sleep. We tested the impact of daytime sleep, either with or without REM, on moral decision. Sixty participants were presented with 12 sacrificial (6 Footbridge- and 6 Trolley-type) and 8 everyday-type moral dilemmas at 9 AM and at 5 PM. In sacrificial dilemmas, participants had to decide whether or not to kill one person to save more people (utilitarian choice), and to judge how morally acceptable the proposed choice was. In everyday-type dilemmas, participants had to decide whether to endorse moral violations involving dishonest behavior. At 12 PM, 40 participants took a 120-min nap (17 with REM and 23 with NREM only) while 20 participants remained awake. Mixed-model analysis revealed that participants judged the utilitarian choice as less morally acceptable in the afternoon, irrespective of sleep. We also observed a negative association between theta activity during REM and increased self-rated unpleasantness during moral decisions. Nevertheless, moral decision did not change across the day and between groups. These results suggest that although both time and REM sleep may affect the evaluation of a moral situation, these factors did not ultimately impact the individual moral choices.

Sleep and moral awareness

The implications of sleep for morality are only starting to be explored. Extending the ethics literature, we contend that because bringing morality to conscious attention requires effort, a lack of sleep leads to low moral awareness. We test this prediction with three studies. A laboratory study with a manipulation of sleep across 90 participants judging a scenario for moral content indicates that a lack of sleep leads to low moral awareness. An archival study of Google Trends data across 6 years highlights a national dip in Web searches for moral topics (but not other topics) on the Monday after the Spring time change, which tends to deprive people of sleep. Finally, a diary study of 127 participants indicates that (within participants) nights with a lack of sleep are associated with low moral awareness the next day. Together, these three studies suggest that a lack of sleep leaves people less morally aware, with important implications for the recognition of morality in others.

Reduced empathic concern leads to utilitarian moral judgments in trait alexithymia

Recent research with moral dilemmas supports dual-process model of moral decision making. This model posits two different paths via which people can endorse utilitarian solution that requires personally harming someone in order to achieve the greater good (e.g., killing one to save five people): (i) weakened emotional aversion to the prospect of harming someone due to reduced empathic concern for the victim; (ii) enhanced cognition which supports cost-benefit analysis and countervails the prepotent emotional aversion to harm. Direct prediction of this model would be that personality traits associated with reduced empathy would show higher propensity to endorse utilitarian solutions. As per this prediction, we found that trait alexithymia, which is well-known to have deficits in empathy, was indeed associated with increased utilitarian tendencies on emotionally aversive personal moral dilemmas and this was due to reduced empathic concern for the victim. Results underscore the importance of empathy for moral judgments in harm/care domain of morality.

Self-reported sleep correlates with prefrontal-amygdala functional connectivity and emotional functioning

STUDY OBJECTIVES

Prior research suggests that sleep deprivation is associated with declines in some aspects of emotional intelligence and increased severity on indices of psychological disturbance. Sleep deprivation is also associated with reduced prefrontal-amygdala functional connectivity, potentially reflecting impaired top-down modulation of emotion. It remains unknown whether this modified connectivity may be observed in relation to more typical levels of sleep curtailment. We examined whether self-reported sleep duration the night before an assessment would be associated with these effects.

DESIGN

Participants documented their hours of sleep from the previous night, completed the Bar-On Emotional Quotient Inventory (EQ-i), Mayer-Salovey-Caruso Emotional Intelligence Test (MSCEIT), and Personality Assessment Inventory (PAI), and underwent resting-state functional magnetic resonance imaging (fMRI).

SETTING

Outpatient neuroimaging center at a private psychiatric hospital.

PARTICIPANTS

Sixty-five healthy adults (33 men, 32 women), ranging in age from 18-45 y.

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Greater self-reported sleep the preceding night was associated with higher scores on all scales of the EQ-i but not the MSCEIT, and with lower symptom severity scores on half of the psychopathology scales of the PAI. Longer sleep was also associated with stronger negative functional connectivity between the right ventromedial prefrontal cortex and amygdala. Moreover, greater negative connectivity between these regions was associated with higher EQ-i and lower symptom severity on the PAI.

CONCLUSIONS

Self-reported sleep duration from the preceding night was negatively correlated with prefrontal-amygdala connectivity and the severity of subjective psychological distress, while positively correlated with higher perceived emotional intelligence. More sleep was associated with higher emotional and psychological strength.