A new research published in the journal Current Biology shows that 34-week old fetuses in the womb can already respond to visual stimulus and are four times more likely to track light that resembles a human face.
The study is a collaborative research by professors from the Lancaster University, Cardiff University, Radboud University, and Ohio State University's Wexner Medical Center.
Thirty-nine women in their third trimester participated in the research, and to determine if fetuses would react to visual stimulus, a high-definition ultrasound was used to track the each fetus' movement during the test.
Stimulating The Fetuses
According to Prof. Vincent Reid from Lancaster University, several studies have already proven that fetuses can already see even in the womb, but none have shown that they actually respond to visual stimulus.
What the team did was to shine a pattern of red lights on the pregnant mother's womb and observe whether it will get any reaction. Two patterns were used during the observation, but only one received better responses.
"We call it face-like. It's not a face, but it has the same sort of parameters as a face, visually," Professor Reid said.
The patterns consisted of three red dots but were shown at different angles. The face-like pattern resembled an inverted triangle wherein the two dots on top would resemble eyes while the one below would look like a mouth. The other pattern showed the three red dots in an upright triangle position.
See the conceptual perception of both patterns below.
Both patterns were flashed from the side of the fetuses' head to determine whether it will pique their interest when something enters their peripheral vision. If it does, the researchers would slowly move the light and monitor whether the fetus would track it. This was done five times for each fetus, for a total of 195 tests.
According to the research findings, the fetuses turned their heads and tracked the face-like pattern 40 times as opposed to the 14 times the other pattern was followed.
"You can actually see the face of the fetus. And then you can actually see them move their face. They would move their heads more to try to track the stimuli when we showed the stimuli in an upright orientation," Reid recounted.
The research does not offer insight with regard to fetal development, but the researchers note that the fetal preference to track the face-like pattern could help scientists further understand the process.