Sleep is that golden chain that ties health and our bodies together” wrote English poet Thomas Dekker in the 17th century (The Gull’s Hornbook, 1609), indicating the close connections between sleep and various aspects of health and psychological functioning (Banks and Dinges, 2007; Roth, 2007).
The strong links between sleep and behavior, as well as cognitive functioning have long been recognized. Surprisingly, the bi-directional links between sleep and emotions have only recently received increased attention.
Sleep is known to be important for health, and the health risks associated with sleep disruption include cancer, metabolic disorders, and cardiovascular illness. The relevance of sleep to psychiatric disorders has also been established.
Poor sleep quality and insomnia are pertinent to emotion, and previous studies have investigated the effects of loneliness, complicated grief, hostility, and impulsivity on sleep.
Sleep and emotion are closely linked, and the importance of this area has been increasingly recognized. Recently, experimental paradigms with social and emotional stimuli (i.e., emotional faces, voices, images, or movies) have been employed to investigate how sleep affects responses to stimuli.
Emotion perception can therefore be defined as the sensory processing of emotional stimuli. Emotion is relevant to the meaning, or significance, which is given to events, and emotion, cognition, and motivation are interlinked. Specifically, emotion can be associated with approach or withdrawal behavioral states, or motivational states of reward and punishment.
Affective states comprise a conscious emotional feeling, with associated autonomic, neuroendocrine, and somatomotor responses. Emotional stimuli are therefore highly relevant for the well-being and survival of the perceiver.
Sleep-deprived people don’t know they are sleep deprived.
Sleep-deprived people thought that they were doing well in reaction time tests conducted by the researchers. Their test results showed that people who lacked sleep do badly on the tests. The results didn’t surprise them, but the lack of awareness of their condition did.
Sleep deprivation gives people sleep goggles
In one of the experiments, results showed that men rated photos of the least attractive models as being more attractive. The effect was not seen among women. In a previous experiment, results showed that men think women want to have sex with them. This effect depends on the type of mattress people slept on. Especially, the correlation was strong for the people who were sleeping on the bamboo mattress.
Sleep deprivation increases pain sensation.
A study conducted by a group from the Komoki Sleep Center in Seoul, Pusan Nation University Yangsan Hospital and the University of Sydney suggested that the tolerance to pain became lower with less sleep at night.
Sleep deprivation makes people less concerned.
Researchers have studied the empathy levels of subjects and seen how sleep-deprived people tend to be less empathetic when looking at hands stung by needles.
Sleep deprivation leads to an increase in delusional beliefs and paranoia.
People who had been awake for 18 hours straight scored higher on the standard tests of global paranoia. People lacking sleep rated higher on depersonalization or feeling separated from one’s thoughts, reality or body.
Sleep deprivation makes people less concerned about money.
People who lack sleep should not be gambling, according to one study conducted by researchers from the University of Pittsburgh. When sleep-deprived people were expecting to lose money, their brain showed less activity in the regions that are connected with the mind’s reward system.
Sleep deprivation prevents people from recognizing emotions of others.
People who lack sleep don’t know the emotions showed by other people. Researchers found out that the lack of sleep makes people concentrate on the lower part of the body.