Original ArticleSleep deprivation reduces perceived emotional intelligence and constructive thinking skills
Introduction
Insufficient sleep can have deleterious effects on personal health, cognitive performance, and safety [1], [2], [3]. Without adequate sleep, individuals show significant impairment in a variety of cognitive abilities, most notably including simple alertness, vigilance, attention, and concentration [4], [5], [6], [7], [8]. There is also evidence suggesting that sleep loss can adversely affect a variety of higher-order cognitive processes, including problem-solving [9], inhibitory control [10], [11], and complex decision-making [12], [13], [14], although there continues to be debate on this subject and findings for executive function tasks have not always been consistent [15], [16], [17], [18]. Many of these higher-order capacities are believed to be mediated by the prefrontal cortex [19], a complex region of the brain that appears to be particularly affected by prolonged wakefulness [20], [21], [22].
Perhaps because logical reasoning has long been considered to be the foundation of human rationality [23], the field of sleep deprivation research has focused primarily on the logical, rational, and purely mechanistic aspects of intellectual and cognitive performance (e.g., working memory, concentration, logical processing, set shifting, etc.). However, emerging evidence suggests that effective human judgment and decision-making involves more than dispassionate logic and rational intellect [24], [25]. While traditional forms of cognitive intelligence are critical to the ability to adapt and survive, most individuals that succeed in modern society demonstrate a number of other capacities as well. Successful individuals are able to regulate their own emotional behaviors in constructive ways, are adept at utilizing their affective processes to guide their judgments and streamline their decision-making, are skilled at identifying and understanding the emotional needs of others, and are effective at acting upon this information in pro-social and self-enhancing ways [26], [27], [28]. Such people are said to think and act in constructive ways [29] and demonstrate qualities of “emotional intelligence” [30].
It has been suggested that emotional intelligence abilities, including self-awareness, interpersonal skills, and adaptive coping skills, are related to better adjustment, and may be as important, if not more so, to a variety of successful life outcomes than traditional cognitive intelligence [30]. In fact, it has been observed that formally measured intellectual capacity is often not the best predictor of many aspects integral to successful living. For example, measures of adjustment including job success, relationship satisfaction, and mental health have been shown to not be significantly associated with intellectual ability [31], [32]. Rather, individuals that show a combination of adaptive problem-solving and emotional and behavioral coping skills appear to be the most successful when faced with highly stressful experiences, a set of skills that have been described as “Constructive Thinking” [29]. Epstein and Meier conceptualize Constructive Thinking as the habitual thought processes that help a person construe and respond to events adaptively and with minimal stress [29]. Because emotionally intelligent individuals are attuned to the subtle nuances of emotions in others and in themselves and can use this information to facilitate effective judgment and streamline decision-making [28], they would also be expected to rely heavily on the emotional and behavioral coping skills involved in constructive thinking.
There is accumulating evidence that a significant proportion of the variance in Emotional Intelligence is rooted in neurobiology. The ability to integrate emotional information with cognitive processing appears to require the interaction of several key brain regions, particularly the ventromedial prefrontal cortex, the insular cortex, and the amygdala [33]. These three brain regions comprise a neural system that integrates emotional states, prior learning, and conscious cognition to guide decision-making [24], [25]. Of these regions, the ventromedial prefrontal cortex is thought to function as the critical integrator of emotional and cognitive information in the service of decision-making [34], [35]. Despite relatively normal levels of cognitive intelligence, patients with damage to the ventromedial prefrontal cortex often exhibit profound impairments in social judgment and deficits in emotionally based decision-making [24], [25], [34], [36]. Thus, dysfunction within the ventromedial prefrontal cortex is associated with impaired emotional intelligence and poor constructive thinking processes, while intact functioning of this region allows the individual to cope flexibly with changing demands.
Interestingly, the prefrontal cortex appears to be particularly sensitive to the effects of sleep loss, with significant declines in metabolic activity evident following as few as 24 h of continuous wakefulness [22], [37]. Functionally, the prefrontal cortex appears to become less efficient at neural processing during prolonged sleep deprivation [38], [39], necessitating the recruitment of additional brain regions to compensate for these deficiencies [40], [41], [42]. Likewise, tests of complex cognitive functions mediated by the prefrontal region often show decrements in performance after one to two nights of sleep loss [20], [21]. This appears to be particularly true for tasks requiring divergent thinking and mental flexibility [43] rather than novel logic-based executive function tasks such as the Wisconsin Card Sorting Test [15], [16]. Recent findings suggest that deficits in emotional decision-making [13], inhibitory control [44], mood regulation [45], [46], moral judgment [47], and responses to frustration [48] also emerge after sleep deprivation. These findings suggest that it is not only pure cognitive abilities that are affected by sleep loss, but also affective functions that are central to personality and social interaction, capacities that are likely to play a central role in emotional intelligence. To address this more directly, the effects of two nights of sleep loss were examined on two well-validated commercially available tests of perceived emotional intelligence and constructive thinking skills. The tests were administered at rested baseline and again following 55.5 h of continuous wakefulness. It was hypothesized that sleep deprivation would produce significant declines in perceived emotional intelligence and constructive thinking scores.
Section snippets
Participants
Twenty-six healthy military volunteers (21 males and 5 females) participated in a larger investigation of the effects of caffeine on psychomotor vigilance. The participants ranged in age from 20 to 35 years (mean [M] = 25.3, standard deviation [SD] = 4.1) and had an average of 14.1 years of education (SD = 1.6). Other data from this sample of volunteers have been presented elsewhere [48], [49], [50], although the results reported herein represent novel and never before published findings about
Perceived emotional intelligence
First, to provide an evaluation of changes in response set as a function of sleep deprivation, several validity and response indices were compared across sessions. No significant change was found for Omissions, Inconsistency Index, Positive Impression Scale, or Negative Impression Scale of the EQi between baseline and sleep-deprived sessions (all p-values > .05), suggesting that the data from the EQi are valid and interpretable. Overall, Total EQ scores declined significantly as a function of
Discussion
Sleep deprivation produced statistically significant declines in several facets of perceived emotional intelligence and some aspects of subjectively assessed constructive thinking skills, including reduced self-reports of intrapersonal awareness, interpersonal functioning, stress management, and behavioral coping skills as well as an elevation in esoteric thought processes. The present scales were subjective in nature and may simply reflect the participant’s own self-perception of declines in
Acknowledgments
This material has been reviewed by the Walter Reed Army Institute of Research and there is no objection to its publication or presentation. The views expressed in this article are those of the authors and do not reflect the official policy or position of the Department of the Army, the Department of Defense, the US Government, or any of the institutions with which the authors are affiliated.
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