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Babies look for faces as soon as they are born, and now it seems they can do this while still a fetus inside the uterus.

“We already know that fetuses can see,” says of Lancaster University, UK. “But until now, no one has displayed visual information to the fetus and triggered a response.”

Reid’s team has done it by shining three red dots through the skin of women in the final trimester of their pregnancies. When the dots were configured to look something like two eyes above a mouth, the team captured 40 occasions where a fetus seemed to track this pattern when it moved.

To watch how the fetus’s head moved, Reid’s team used high-definition ultrasound. The team shone the red lights in a pattern to one side of the fetus’s head, and moved them slowly, to see if the fetus turned to track it. “We were focusing on peripheral vision,” says Reid.

Three little dots

The group used red light because it is the best at getting through to the uterus. As a control, the team inverted the three dots – one dot sitting above two dots, instead of two dots sitting above one. This experiment replicates those conducted in the 1990s that identified what newborn babies preferentially look at, says Reid.

The team tested both patterns on 39 healthy fetuses during the final third of pregnancy, five times each. Out of 195 tests of each configuration, fetuses turned to follow the “face” shape 40 times, and the inverted image only 14 times. “It’s definitely a robust finding. What matters is the difference between the conditions,” says Reid.

“We know that fetuses receive a lot of sensory stimulation from the outside world,” says at the University of New Mexico, Albuquerque. In 2011, Del Giudice’s team showed that on a bright summer’s day, with no clothing in the way, a fetus receives the same amount of light you get in a typically lit house.

Womb with a view

“This brilliant new study demonstrates how we can use these windows to learn how the remarkable skills of human infants begin to develop before birth,” says Del Giudice. “I’ve suggested, for example, that fetuses might develop some visual and coordination skills by observing the movements of their own hands and feet.”

The study doesn’t tell us much about how a fetus naturally develops, says at Birkbeck College, London, whose team demonstrated in 1991 that newborns preferentially turn to look at faces. “The circumstances are very much unlike anything that would happen in the real world.”

“But it’s interesting that these predispositions might be there from earlier on to prepare the infant for birth,” Johnson says.