We’ve all been there: after a bad night’s sleep, the next day we can’t even stand the neighbor who greets us in the elevator. We’re annoyed by traffic, the sound of the microwave, and even the dog’s breathing. But beyond a bad mood and dark circles, did you know that poor sleep can also make you less generous, less empathetic, and, ultimately, more selfish?
Does sleeping less than 8 hours dehumanize us?
We’re programmed to live in community: to help each other, to support each other, to lend a hand when we need it… These behaviors are the “social glue” that keeps us together. However, a study conducted at the University of California revealed that when we sleep poorly, our capacity for cooperation crumbles like a sandcastle.
In other words, sleep not only affects your concentration, it also interferes with your basic social awareness. Lack of sleep will diminish your desire and willingness to help others, so you’re likely to become much less empathetic.
In fact, did you know that when the clocks in the United States are moved forward for Daylight Savings Time and the population loses an hour of sleep, charitable donations decrease by 10%? Yes, one hour less sleep can be enough to make us less generous. Exactly.
Lack of sleep disconnects us from others
These neuroscientists followed more than 100 people for several days. They assessed the quality of their sleep and their willingness to help others with simple actions such as holding a door or assisting a stranger. They found that when someone had slept poorly, their willingness to help was significantly reduced the next day.
That is, you won’t just be grumpier: you’ll also be less likely to cooperate, listen, understand… Although perhaps the most worrying thing is that this “sleepy selfishness” is contagious.
In previous studies, these same researchers discovered that sleep-deprived people tend to isolate themselves socially… and they transmit that feeling of isolation to others. Like a spreading emotional virus, it dulls the connection between people.
In fact, they found that those who come into contact with a sleep-deprived person, even for a brief one-minute interaction, feel lonelier, indicating a viral contagion of social isolation caused by sleep deprivation.
But how is it possible that lack of sleep makes us so unempathetic?
Sleeping brain, empathy turned off
In a first study, 24 people underwent a brain MRI after either a good night’s sleep or a sleepless night. The result? The brain areas responsible for empathy and understanding the needs of others (known as the theory of mind network) were much less active in the insomniacs.
This network is activated when we empathize with others or try to understand their desires and needs. It prompts us to ask ourselves: What are they thinking? Are they in pain? Do they need help? And try to find the answers.
This literally means that when we don’t sleep well, our mirror neurons have a harder time putting themselves in someone else’s shoes. Therefore, we may become more distant, indifferent, and selfish.
On the other hand, it has also been observed that sleeping less than 8 hours generates hypersensitivity in the brain regions that detect human approach. In other words, they activate a social repulsion signal, as if the mere fact that someone approached us triggered an internal alarm.
Under normal conditions, the brain interprets physical closeness as neutral or even positive, a sign of social connection and security. But when we’re sleep-deprived, those same regions, instead of relaxing, go on guard. This social aversion response generates an automatic impulse to withdraw, avoiding contact and interaction. In other words, we become more aloof, shifty, and avoidant.
And all of this doesn’t mean we’re bad people; it just means our brains are in energy-saving mode. If we can barely stay awake, it’s understandable that helping others isn’t among our most immediate priorities and that the mere prospect of social relationships overwhelms us.
Sleeping well is a necessity, not a luxury.
In a society driven by productivity and where we’ve developed a constant fear of missing out, we sleep less and less. However, sleep isn’t a luxury or a whim: it’s a necessity. Not only for our health, but also for living better in society.
Getting enough sleep makes us better people—kinder, more caring, and more humane. So maybe the next time you feel less patient with your partner, more irritable with your children, or less willing to listen to your colleague, before you think you need to change your lifestyle or sign up for a yoga class… think about how many hours of sleep you got last night. Maybe all you need to calm down is better sleep habits.
Bibliographic References:
Simon, B. et. Al. (2022) Sleep loss leads to the withdrawal of human helping across individuals, groups, and large-scale societies. PLoS Biol; 20(8): e3001733.
Simon B. & Walker, M. P. (2018) Sleep loss causes social withdrawal and loneliness. Nat Commun; 9(1): 3146.
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