### 1. **The Social Impact of Sleep Deprivation**

Cooperation and helping one another are among the foundational forces of human civilization. But what determines whether we choose to help others? A new study suggests that our sleep may play a critical role.

It is well-known that insufficient sleep increases the risk of cardiovascular diseases, diabetes, hypertension, and overall mortality. Many studies have also shown a strong link between sleep health and mental health. In fact, no mental illness is known to coexist with normal sleep patterns.

A recent study published in *PLOS Biology* reveals that sleep deprivation not only harms individual physical and mental health but also undermines one of society’s most basic virtues—our willingness to help others. It diminishes social interactions and can ultimately impact the very fabric of human society.

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### 2. **Three Independent Experiments**

To assess the effects of sleep deprivation on people’s willingness to help others, researchers conducted three independent experiments:

#### **Experiment 1**

In the first experiment, 24 healthy participants took part in a controlled crossover study. They spent two nights in a lab: one with a full 8 hours of sleep and the other staying awake all night. In the morning, participants completed a standardized "altruism" questionnaire that assessed their likelihood of helping strangers or acquaintances.

Participants rated a series of scenarios on a scale of 1 to 5, where 1 meant "least likely to help" and 5 meant "most likely to help." Scenarios included offering a seat to a stranger on public transport, giving a colleague a ride, or holding an elevator door open for someone. No scenario was repeated.

Results showed that 80% of participants were less willing to help others when sleep-deprived compared to when well-rested.

Additionally, researchers used functional MRI (fMRI) to observe participants' brain activity after both 8 hours of sleep and a sleepless night. They found that regions of the brain associated with empathy were less active when participants were sleep-deprived.

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#### **Experiment 2**

In the second experiment, researchers recruited 136 participants online and monitored their sleep over four nights. Sleep duration and quality were assessed based on factors such as total sleep time and the number of awakenings. Participants then completed the same "altruism" questionnaire by 1 PM the next day.

The findings revealed that poor sleep quality on a given night led to a significant drop in the willingness to help others the following day. Participants who experienced longer wake times during the night scored lower on the altruism questionnaire the next day.

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#### **Experiment 3**

In the third part of the study, researchers analyzed donation data from a U.S. charity between 2001 and 2016. They found that at the start of daylight saving time—when people lose an hour of sleep—charitable donations decreased by 10%. In contrast, states like Hawaii and Arizona, which do not observe daylight saving time, showed no changes in donation patterns.

This suggests that even losing just one hour of sleep can significantly impact altruistic behavior.

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### 3. **The Simplest Kindness**

Earlier studies by the same team had already shown that sleep deprivation can make people feel more socially isolated. They found that not only does sleep deprivation increase feelings of loneliness, but it also "spreads" loneliness to others during interactions, much like a virus.

This new research takes it a step further, showing that the quantity and quality of sleep can affect not just individuals but society as a whole. Sleep is crucial to every aspect of our physical, mental, and emotional well-being. Sleep deprivation makes us less empathetic, less generous, and more socially withdrawn, and these emotions can spread to others.

In developed nations, more than half the population rarely gets sufficient sleep on workdays. When sleep is undervalued, we may encounter sleep-deprived doctors, police officers, and teachers, leading to less empathetic and less friendly interactions in daily life.

Unlike other large-scale problems like climate change, addressing sleep deprivation has a clear solution: getting enough sleep. Providing ourselves and those around us with this "simplest kindness" might just be the easiest way to improve our lives and communities.