Are night owls more sadistic? a new study says yes and the reason is fascinating
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KEY TAKEAWAYS
Night owls show a modest but measurable higher tendency toward everyday sadism compared to morning people, based on two distinct studies.
Everyday sadism refers to a mild enjoyment of others' discomfort, distinct from clinical or violent sadism, and is part of the Dark Tetrad personality traits.
The niche-specialisation hypothesis suggests dark personality traits and nocturnal preferences co-evolved because exploitative behaviors were more effective under the cover of night.
The research findings are correlational and population-level, meaning being a night owl does not predict individual character or dangerous behavior.
Night owls also tend to score higher on other dark traits and face higher risks for depression, reflecting a complex biological and psychological profile shaped by evolutionary forces.
GLOSSARY
Everyday Sadism
A psychological trait describing a mild but measurable tendency to enjoy others' discomfort, distinct from clinical sadism.
Chronotype
An individual's natural preference for activity and alertness at certain times of day, such as being a night owl or morning person.
Dark Tetrad
A set of four distinct dark personality traits: narcissism, psychopathy, Machiavellianism, and everyday sadism.
Niche-Specialisation Hypothesis
An evolutionary theory proposing that dark personality traits and nocturnal activity co-evolved because exploitative behaviors were more successful at night.
Bug-Killing Paradigm
An experimental method where participants choose whether to operate a device that appears to kill insects, used to measure behavioral sadism.
Correlational Study
Research that identifies statistical relationships between variables but does not establish causation.
FAQ
Does being a night owl mean someone is a sadistic or dangerous person?
No, the research shows only a modest average increase in everyday sadism among night owls at the population level. Most night owls do not exhibit sadistic behavior, and the findings do not imply individual character judgments.
What exactly is everyday sadism as used in this research?
Everyday sadism refers to a mild psychological tendency to enjoy others' discomfort or misfortune, such as finding satisfaction in watching someone fail or making cutting remarks. It is distinct from clinical or violent forms of sadism.
How did the researchers measure sadistic tendencies beyond self-report questionnaires?
In addition to questionnaires, the researchers used a behavioral test called the bug-killing paradigm, where participants chose whether to operate a device that appeared to kill insects, providing observable evidence of sadistic behavior.
What is the niche-specialisation hypothesis and how does it explain the link between night owls and dark traits?
The niche-specialisation hypothesis suggests that dark personality traits and nocturnal activity co-evolved because exploitative behaviors were more effective at night when detection was less likely. This evolutionary perspective explains the association without implying causation.
Are the findings about night owls and dark traits definitive and causal?
No, the studies are correlational and cannot prove causation. Other unmeasured factors may influence both sleep preference and sadistic tendencies, and the relationship could be bidirectional or influenced by third variables.
EDITORIAL NOTE
This piece is part of The Present Minds — essays on psychology, identity, and modern life.
Posted by The Present Minds • March 10, 2026 • Current
Are night owls more sadistic? a new study says yes and the reason is fascinating
Are night owls more sadistic? It sounds like the kind of question designed to generate outrage clicks. It is also, as of December 2025, a question with a genuine scientific answer.
Before you check what time you went to bed last night, it is worth understanding what this finding actually means, what it does not mean, and why the explanation behind it is considerably more interesting than the headline.
The Study and the Bug Machine
The research was published in December 2025 in the journal Chronobiology International. It was conducted by Heng Li, a researcher at Sichuan International Studies University in China, who had been watching something specific during the COVID-19 pandemic.
Night owls, he noticed, seemed more likely to disregard public health guidelines. Not because they were misinformed. Not because they were reckless. Something else. He began wondering whether people who are active at night might have a systematically different relationship to other people’s suffering.
To test the idea he ran two studies. The first used 170 university students and self-report questionnaires measuring chronotype alongside established scales for sadistic personality. The correlation was there. Evening types scored higher on sadism measures than morning types.
The second study went further. It recruited 214 adults, a broader non-student sample, and introduced what researchers call a bug-killing paradigm. Participants were shown a coffee grinder modified to appear as though it could crush live insects. They were told bugs would be placed inside it. They were given the choice: volunteer to be the exterminator, or do something else.
Twenty-five people chose to operate the machine. When the researchers analysed the data, a person’s sleep preference was a statistically significant predictor of whether they chose to crush the bugs. Night owls were meaningfully more likely to volunteer.
This matters because it moves the finding beyond self-report. It is one thing to score differently on a questionnaire. It is another to make a behavioural choice that reflects an actual appetite for causing harm.
What Everyday Sadism Actually Means
The term sadism in this research does not mean what most people picture when they hear it.
Everyday sadism is a psychological construct describing a mild but measurable tendency to enjoy other people’s discomfort. It is not clinical. It is not violent. It is the person who finds a particular satisfaction in watching someone fail. Who enjoys arguments a little more than is strictly necessary. Who chooses the more cutting remark when a neutral one would have sufficed. Who laughs at something that hurts someone else and feels, briefly, better for it.
Research over the past decade has identified everyday sadism as a meaningful personality dimension that predicts certain behaviours independently of other dark traits. It has been proposed as the fourth component of what researchers now call the Dark Tetrad: narcissism, psychopathy, Machiavellianism, and sadism. Each trait is distinct. Each predicts different patterns of behaviour. Together they describe the architecture of what psychologists mean when they talk about dark personality.
Night owls scoring higher on everyday sadism does not mean that people who prefer late nights are dangerous. It means that, on average, they are slightly more likely to experience the mild, everyday version of that trait than people who prefer mornings.
Why Darkness and Dark Personalities May Go Together
The hypothesis begins with an evolutionary observation. Humans with dark personality traits, those who manipulate, exploit, and deceive, face a practical problem. These strategies work best when detection is unlikely. In ancestral environments, detection was least likely at night. Low light, reduced visibility, diminished cognitive sharpness in people who had been awake all day. Night was the ideal operating environment for anyone whose social strategy depended on not being caught.
Over generations, the argument goes, dark traits and nocturnal preference may have been selected together. Not because darkness causes cruelty but because the combination was adaptive. The cheater strategy, as researchers call it, works best in the dark. So the people most inclined toward it may have gradually become the people most inclined toward the dark.
This is why the finding connects specifically to the niche. It is not that staying up late makes you cruel. It is that the personality traits associated with nocturnality and those associated with exploitative social strategies may have developed in parallel, reinforcing each other across evolutionary time.
What This Is Not Saying
Are night owls more sadistic than morning people on average? The research says yes, modestly and measurably.
Does that mean night owls are bad people? No.
The effect size in both studies is real but not large. The vast majority of people who prefer staying up late are not sadistic in any meaningful sense. Chronotype is one variable among dozens that shape personality. The researchers themselves are explicit about the limitations. The studies are correlational. They cannot prove causation in any direction. It is possible that a third unmeasured variable influences both sleep preference and sadistic tendency simultaneously. It is possible the relationship runs in the opposite direction entirely.
This is the level of precision at which population psychology operates. It is useful for understanding patterns. It is useless for judging individuals.
The Darker Portrait of Night Owls
This is not the first time research has painted night owls in unflattering colours.
The emerging portrait is of a chronotype that is more cognitively flexible in certain ways, more willing to take risks, more creative in some research, and also more prone to a cluster of traits that tend toward social exploitation, emotional dysregulation, and difficulty with the structures that morning-oriented societies have built for morning-oriented people.
The night owl is not a villain. But the research suggests they are not simply a romantic archetype of creative rebellion against conventional schedules either.
They are a biological type, shaped by forces that predate alarm clocks and office hours by several hundred thousand years, carrying tendencies that were once adaptive and now express themselves in the specific social and psychological textures of modern life.
Are night owls more sadistic? A little. On average. As a group.
What you do with that information, and what time you choose to read it, is entirely your own business.
Some links on this page may be affiliate links. If you purchase through them, we may earn a commission at no extra cost to you.
Written by
The Present Minds
Administrator
A digital sanctuary for the overstimulated.
Clarity. Depth. Silence.
KEY TAKEAWAYS
Night owls show a modest but measurable higher tendency toward everyday sadism compared to morning people, based on two distinct studies.
Everyday sadism refers to a mild enjoyment of others' discomfort, distinct from clinical or violent sadism, and is part of the Dark Tetrad personality traits.
The niche-specialisation hypothesis suggests dark personality traits and nocturnal preferences co-evolved because exploitative behaviors were more effective under the cover of night.
The research findings are correlational and population-level, meaning being a night owl does not predict individual character or dangerous behavior.
Night owls also tend to score higher on other dark traits and face higher risks for depression, reflecting a complex biological and psychological profile shaped by evolutionary forces.
GLOSSARY
Everyday Sadism
A psychological trait describing a mild but measurable tendency to enjoy others' discomfort, distinct from clinical sadism.
Chronotype
An individual's natural preference for activity and alertness at certain times of day, such as being a night owl or morning person.
Dark Tetrad
A set of four distinct dark personality traits: narcissism, psychopathy, Machiavellianism, and everyday sadism.
Niche-Specialisation Hypothesis
An evolutionary theory proposing that dark personality traits and nocturnal activity co-evolved because exploitative behaviors were more successful at night.
Bug-Killing Paradigm
An experimental method where participants choose whether to operate a device that appears to kill insects, used to measure behavioral sadism.
Correlational Study
Research that identifies statistical relationships between variables but does not establish causation.
FAQ
Does being a night owl mean someone is a sadistic or dangerous person?
No, the research shows only a modest average increase in everyday sadism among night owls at the population level. Most night owls do not exhibit sadistic behavior, and the findings do not imply individual character judgments.
What exactly is everyday sadism as used in this research?
Everyday sadism refers to a mild psychological tendency to enjoy others' discomfort or misfortune, such as finding satisfaction in watching someone fail or making cutting remarks. It is distinct from clinical or violent forms of sadism.
How did the researchers measure sadistic tendencies beyond self-report questionnaires?
In addition to questionnaires, the researchers used a behavioral test called the bug-killing paradigm, where participants chose whether to operate a device that appeared to kill insects, providing observable evidence of sadistic behavior.
What is the niche-specialisation hypothesis and how does it explain the link between night owls and dark traits?
The niche-specialisation hypothesis suggests that dark personality traits and nocturnal activity co-evolved because exploitative behaviors were more effective at night when detection was less likely. This evolutionary perspective explains the association without implying causation.
Are the findings about night owls and dark traits definitive and causal?
No, the studies are correlational and cannot prove causation. Other unmeasured factors may influence both sleep preference and sadistic tendencies, and the relationship could be bidirectional or influenced by third variables.
EDITORIAL NOTE
This piece is part of The Present Minds — essays on psychology, identity, and modern life.
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