I thought we were just friends! Emergence of Sexual Misperception Biases in Adolescence

– by Marius Stavang

Imagine you’re on a movie date with someone. Everything seems to be going great. The conversation flows easily, you laugh together, you exchange smiles—there’s chemistry. After the movie, you walk them home. On their doorstep, you exchange a lingering look and a shared laugh about how good—or bad—the movie was. The moment feels perfect. There are sparks. Nervous, but summoning what courage you can, you close your eyes, purse your lips, and lean in for a kiss.

Suddenly you’re interrupted with a loud protest, “I thought we were just friends!”  Your heart sinks immediately, you feel devastated, crushed, and also—deeply ashamed. You realize you’ve misinterpreted the relationship between the two of you. You mistook their friendliness for romantic interest. Meanwhile, your friend—confused and saddened by what’s happening—feels their own sting of guilt and embarrassment. How could they not have seen that your invitation might have meant something more?

In evolutionary psychology, these two errors of inference are referred to as sexual overperception and sexual underperception. Sexual overperception involves mistaking someone’s friendliness for romantic interest, whereas sexual underperception involves mistaking romantic interest for mere friendliness.

If people were always completely transparent about their romantic interest—“Hey, I fancy you as a long-term romantic partner. Want to go see a movie together?”—errors in sexual perception wouldn’t occur. But for some reason humans are highly anxious and cautious about revealing their non-platonic interest. Instead, we engage in a subtle dance, gradually signaling that we want “something more,” while trying to infer whether the other person is spending time with us for the same reason. And because humans are imperfect mind readers, errors in sexual inference are inevitable.

It also turns out that men and women are not equally likely to sexually over- or underperceive one another. A large body of research shows that men are more likely to overperceive women’s interest than to underperceive it, whereas women are more likely to underperceive men’s interest than to overperceive it. The magnitude and consistency of these sex differences have led researchers to label them the male sexual overperception bias and the female sexual underperception bias.

Put simply, men tend to overestimate how keen women are on them, while women tend to underestimate how keen men are on them. These sexual misperception biases have been identified consistently in adults across a wide range of methods. But an important question remains: When do these biases emerge in development? At what age do males begin to overperceive female’s interest—19, 17, or perhaps as early as 14? And when do females begin to underperceive male’s interest?

We wanted to find out. Studying topics related to sex among those under 18, however, is—for good reason—highly sensitive and requires great caution. For cultural, practical, and ethical reasons, it is not feasible to ask very young individuals directly about their socio-sexual inference making.

This means there is a lower age limit for what can reasonably be studied. For us, that limit was 16. Using a Norwegian high-school sample of adolescents aged 16 to 19 (N = 1 290), we asked participants to report how often, over the past 12 months, their friendliness had been mistaken for sexual interest—and how often their sexual interest had been mistaken for friendliness.

The results showed that from ages 16 to 19, girls were increasingly—and seemingly linearly—more likely to be overperceived. From age 17 onward, they reported that males exhibited an overperception bias. Boys, on the other hand, were consistently underperceived from age 16, and the frequency of these reports did not change with age. Taken together, these findings suggest that male’s sexual overperception bias strengthens throughout mid-to-late adolescence and may first emerge around age 17. In contrast, female’s sexual underperception bias appears to be activated and relatively stable already by age 16.

In sum, the findings suggest that from age 16 onward, males and females are already heavily engaged in inferring one another’s romantic interest. Like adults, they are frequently exposed both to misinterpreting others and to being misinterpreted themselves—boys more often ending up disappointed and ashamed for overestimating others’ interest, and girls more often confused, embarrassed, and even guilty for feeling they should have noticed that others wanted something more.

Thus, unless someone makes it trendy to disclose romantic interest upfront, the “likes me, likes me not” guessing game will forever remain a classic.

Stavang, Marius, Bendixen, Mons, & Kennair, Leif Edward Ottesen. (2025) Adolescent development of sexual misperception biases: females increasingly overperceived, males consistently underperceived. Evolution and Human Behavior, 46, 106758.

Hot hand thinking in children

– by Andreas Wilke

People often see patterns in completely random data sets, expecting streaks and clumps where none exist. Maybe you’ve recently felt like you’re “on a roll,” or spotted an interesting pattern that later turned out to be non-existent. Here’s the fascinating twist: This tendency isn’t just found in adults. Our new research shows that children as young as three share this propensity—and often even more strongly than adults.

Our recent study published in Evolution and Human Behavior explores how these misperceptions of randomness develop in early childhood. Our findings confirmed something profound about human cognition: Our brains are essentially “wired” to expect streaks and clumps, because, for most of our evolutionary history, resources in nature that we foraged for weren’t random—they were patchy, where a resource encounter often predicted another encounter. If you cast your line and catch a fish, you’re actually pretty smart in thinking more fish may be nearby as well. Similarly, if the first person you encounter in a village speaks your language you will assume others will too. But while we evolved in a world filled full of positively auto-correlated patterns, there are many modern-day settings where events are completely independent leading us to make poor inferences.

Our research reminds us that what sometimes looks like a cognitive fallacy—such as the well-researched hot hand phenomenon—may actually be a design feature, a mental shortcut tuned for survival and resource search in patchy environments. Our brains evolved to expect clumps because, in nature, pure randomness was (and still is) quite rare. This evolved adaptation now still colors how we see the world, from interpreting sequential events to predicting spatial arrangements in various life domains.

So why do we do this? Evolutionary cognitive psychologists argue that this propensity is actually rational from an ecological and evolutionary perspective. For millions of years, humans foraged in environments where resources—plants, animals, water—were clumped together. If you found berries in one spot, chances were good you’d find more nearby. Assuming clumpiness was adaptive for survival, and using any other search strategy in truly random environments would not have lead to lower payoffs. Today, that same mental shortcut misfires in domains like sports, gambling and finance, where outcomes can be truly random.

Until now, research on the hot hand phenomenon focused on adults. Our team wanted to know: When does this bias emerge developmentally? Is it learned through experience, or is it an evolved default present from birth?

To find out, we tested more than 300 children aged 3 to 10 in the U.S. and Germany, using three playful, tablet-based decision-making tasks:

  1. The animal foraging task: Children helped a cartoon rabbit guess whether a carrot was hidden under each spot along a path. The resource sequence path was random, but we measured whether they expected to find clumps of carrots.
  2. The raindrop task: Young participants tapped where they thought raindrops would fall on a basketball court, revealing their mental model of randomness also in two-dimensional space.
  3. The tree task: Children placed apples (which “like to grow close together”) and bird nests (which “like to be spaced out”) on a tree, testing their grasp of positive and negative spatial dependency.

Across all three tasks, children showed a strong bias toward streaks and clumps.

In the animal foraging task, younger children (ages 3–7) consistently predicted streaks, with subjective alternation probabilities well below the objective random benchmark. Older children (ages 8–10) were somewhat better in the task, but often reverted to seeing more clumps in the sequence the longer they played the game.

In the raindrop task, nearly every child produced a pattern that was highly aggregated, as if raindrops fall in clusters. Very few children—often only of older age— created actual random distributions.

In the tree task, kids were better at grouping apples together than spreading bird nests apart, suggesting an earlier readiness for reasoning with positive spatial dependency (clumping) and a delayed grasp of negative dependency (dispersion).

Overall, these assumptions of clumpiness weakened with increased age, but even 10-year-olds still lacked a sound understanding of randomness. Adults, tested in comparison benchmark samples, were more accurate—but also far from perfect.

These findings suggest that hot hand thinking isn’t just a cultural artifact or learned disposition. It appears early in life, likely reflecting an evolved cognitive default shaped by our species’ foraging past. For most of human history, assuming clumps was a smart bet. Today, that same bias can lead us astray.

There are intriguing possibilities for future research. On the one hand, we believe it would be informative to look for ways to identify hot hand thinking even earlier in life—including during infancy, to see what expectations of clumpiness look like, with the most minimal experience and exposure to socio-cultural context. On the other hand, further investigations could look at the effects in later life, say during adolescence, and develop educational trainings to help young people learn what truly random patterns look like.

Understanding this developmental trajectory has practical implications. Teaching statistical literacy early on could help children distinguish real patterns from random noise. This is crucial for science education and decision-making under uncertainty. Since stronger misperceptions of randomness are linked to increased gambling risk, interventions targeting these biases in youth could help reduce problem or pathological gambling later on in life.

So the next time you catch yourself seeing a streak or a pattern in the world out there, remember that it might not be real. It’s a deeply human tendency—one that starts in childhood and tells a story about our evolutionary past.

Wilke, A., DeLaBruere, G., Garcia, Y., Spilman, H., Pedersen, S., Han, B.-H., Barrett, H. C., Todd, P. M., & Wertz, A. E. (2025). Hot hand thinking in children. Evolution and Human Behavior, 46, 106743.

 

Royal Society – Philosophical Transactions – Special Issue on Cultural Evoultion

HBES Members,

A new issue of Philosophical Transactions B expands the field of cultural evolution and shows why it matters for today’s biggest challenges – from inequality and cooperation to conservation and education. Transforming cultural evolution research and its application to global futures (compiled and edited by Adam H Boyette, Sarah Mathew, Stephen Asatsa, Michael Chimento and Rachel L Kendal) can be accessed for free at https://royalsocietypublishing.org/rstb/issue/380/1940

Also recently published from Philosophical Transactions B is A solid base for scaling up: the structure of numeration systems (compiled and edited by Andrea Bender, Jean-Charles Pelland, Simon J Greenhill and Mary Walworth) can be accessed at https://royalsocietypublishing.org/rstb/issue/380/1937.

Post Doctoral Associate: Evolutionary Medicine & Human Behavior

The evolve-D lab, under the direction of Siobhán Cully in the Department of Anthropology seeks a postdoctoral researcher to join interdisciplinary projects addressing evolutionary medicine and human behavior. This is a calendar year position. Candidates with experience in quantitative, laboratory, or field-based methods and/or theoretical expertise in the evolution of kinship, gendered labor divisions, or disability are encouraged to apply. A Ph.D. in anthropology, biology, demography, statistics, or a related field is required. The position offers a flexible start date, competitive salary, and full benefits. Hybrid appointments will be considered.

To apply, please submit a CV, cover letter, and names of three references. The priority screening date will be January 3, 2026.

Click here for more information.