The ability of babies to recognise faces develops in the womb rather than after birth, new research from the UK shows.
A team of scientists led by Vincent Reid and Kirsty Dunn of Lancaster University used 4D ultrasound imaging to track the reactions of 39 third-trimester foetuses when face-like images were projected into the uterus.
The images comprised face-like arrangements of light shone through the uterine wall. Some were projected upright, and others inverted.
As the lights moved through the foetuses’ fields of vision, the researchers monitored head movements, and found they followed the upright images far more often than the inverted ones. This, says Reid, indicates an active ability to recognise faces.
“There was the possibility that the foetus would find any shape interesting due to the novelty of the stimulus,” he says.
“If this was the case, we would have seen no difference in how they responded to the upright and upside-down versions of the stimuli. But it turned out that they responded in a way that was very similar to infants.”
Until now, it was assumed that a newborn’s ability to fixate on a face was a response learned after birth. The new findings strongly suggest it develops, by a still unknown mechanism, in the womb.
The research also demonstrated that foetuses can and do react to light refracted through maternal tissue. This may influence prenatal perception and cognition.
However, Reid cautioned expecting mothers against shining torches through their bellies.
The study is published in the journal Current Biology.