Third-trimester fetuses can recognize facelike patterns of light shown to them in the womb, according to a new study.
Researchers say the study indicates that babies are neurologically prepared even before birth to recognize faces. The noninvasive methods used also open the door to further study of cognition in fetuses.
The study was published Thursday in Current Biology. Vincent Reid of Lancaster University in the United Kingdom was the first author. Nadja Reissland of Durham University in the UK was the senior author.
Researchers presented 39 fetuses with a facelike pattern projected through their mothers' abdomen, along with an inverted pattern. Their movements were tracked with high-resolution ultrasound.
The 34-week fetuses preferentially turned in the direction of the facelike stimulus, which corresponded to two eyes and a mouth. When inverted, the pattern failed to evoke that response.
The study also confirmed that human fetuses can receive enough light for perception, something that previously hadn't been clear.
"Recent modeling work has indicated a substantially greater luminance within the uterus than previously thought," the study stated.
"Animal models have demonstrated not only that light penetrates into the uterus but also that light penetration is critical in mice for preparing the eye and light response pathway for postnatal vision. Together, these studies indicate that visual experience starts prenatally."
