Are Girls Born Paying More Attention Than Boys?

Newborn girls spent about 59 percent of their attention on a human face compared with just 51 percent for newborn boys, according to a new Cambridge study of babies averaging only 33 hours old. Boys, it turns out, split their gaze almost evenly between the face and a swinging Newton’s Cradle toy, while girls clearly leaned toward the face.

This matters because scientists have spent decades arguing over why men and women, on average, tend to behave differently in social situations. Is it because parents, teachers, and society raise boys and girls differently, or is some of it set before birth? Newborns are one of the only ways to get at that question, since they have barely had time to absorb the world around them. A baby who is 33 hours old has not yet learned to copy a parent’s smile or picked up on subtle social cues from a sibling. Whatever preferences show up that early are hard to explain through upbringing alone.

Researchers at Cambridge revisited a controversial and often-criticized study from the year 2000 that first suggested baby boys and girls look at faces differently right out of the gate. That original research was small, used a live human face instead of a controlled video, and other scientists never successfully repeated it. This new version, published in the journal Biology of Sex Differences and involving 130 newborns, was designed to address those problems and test whether the original finding would hold up.

How Researchers Tested Newborn Attention to Faces

Researchers recruited newborns from postnatal wards at the Rosie Hospital in Cambridge, UK, with parents giving written consent. To avoid steering parents’ expectations, the study was described to families as a broader look at how birth factors, family history, and parental traits relate to a baby’s looking habits, rather than a study specifically about differences between girls and boys.

Out of 200 babies originally recruited, the final group used for analysis was 130 healthy, full-term newborns, 67 boys and 63 girls, averaging just 33 hours old. Babies who could not stay awake and attentive during testing, or whose gaze data did not align closely enough between observers reviewing the footage, were dropped from the study, which the researchers describe as a normal and expected loss for this kind of research.

Each baby was held in a caregiver’s lap about eight inches from a laptop screen and shown a 70-second video featuring two things side by side: a filmed human face, played by a woman in her early 20s making pleasant expressions and natural head movements, and a Newton’s Cradle, the desk toy with swinging metal balls that move in a steady, repeating pattern. The two videos matched in size and lighting and broadly in overall motion, though researchers deliberately kept the toy distinct from a face so a newborn’s brain wouldn’t mistake one for the other. The left-right placement of the face and the toy was also switched from baby to baby, to rule out any bias toward one side of the screen.

Trained observers, who did not know each baby’s sex, watched the recordings and timed exactly how long each infant looked at the face versus the toy. To keep the measurements reliable, the final analysis used only footage in which at least two separate observers landed within 10 percent of each other’s numbers.

What the Study Found About Newborn Girls and Boys

When attention was measured as a percentage, meaning how a baby split looking time between the two options, girls spent close to 59 percent of their attention on the face on average, while boys spent closer to 51 percent. That gap held up statistically.

Raw looking time told a slightly different story. Girls clearly looked longer at the face than at the toy. Boys, on the other hand, showed no real preference either way. But comparing boys to girls directly on raw looking time alone did not turn up a real difference. In other words, the two groups differed in how they divided attention between the face and the toy, not in the total time spent looking at the face.

Across the entire group, regardless of sex, babies showed a general preference for the face over the toy, which aligns with a large body of past research showing that even very young infants are drawn to faces. What stood out here was that girls leaned into that preference more heavily than boys did.

Researchers also checked whether things like how the baby was delivered, birth weight, length of pregnancy, or how long it had been since the baby’s last nap or feeding could explain the difference between sexes, and none of those factors changed the results. Girls were also somewhat more likely than boys to finish the test in a single attempt rather than needing repeat trials, though accounting for that did not erase the difference either.

What This Might Mean for Newborn Development

Because these babies were only about a day and a half old on average, the researchers argue that biological factors present before birth are a reasonable candidate for explaining the pattern, pointing specifically to hormones in the womb as one possibility. Male fetuses are exposed to far more testosterone than female fetuses during early pregnancy, and past research has linked higher testosterone exposure before birth to differences in things like eye contact and reading emotions later in childhood. A similar hormonal influence showing up this early in a baby’s visual attention would fit that pattern, though the authors caution that studies linking prenatal testosterone to later behavior have produced inconsistent results and await independent replication.

At the same time, the authors note that hormones are not the only possible explanation. Girls, on average, tend to develop slightly faster than boys in the earliest days of life, and that gap in maturity could make it easier for baby girls to process a moving image as detailed as a face. It is also possible that something about the look of the face video itself, rather than its social meaning, is driving part of the effect. The researchers built the toy video to look and move differently on purpose, so it wouldn’t be mistaken for a face, but they admit that differences in how the two videos appear to a newborn’s eyes can’t be fully ruled out.

Beyond the immediate result, the authors connect their findings to a bigger question. Several conditions, including autism, show up far more often in boys than in girls, and some researchers believe that has roots in early differences in social attention. If differences in how babies divide attention between people and objects are present within the first two days of life, that raises the possibility that these early patterns play some role in later development, though the study stops well short of proving that link.

What this research adds is a large, carefully controlled attempt to retest a finding argued over for 25 years. Girls, on average, gave more attention to a face than to a toy, and that pattern showed up so early that postnatal experience had little time to shape it. Whether the cause is hormones, developmental pace, or something about how a newborn brain processes what it sees, the fact that the difference appears this early is hard to dismiss.