Humans - while still fetuses in the womb - explore their bodies as part of their development and even learn how to anticipate touch, according to new research.
High tech 4-dimensional scanning made the discovery possible. The findings are published in the journal Developmental Psychobiology.
"What we have observed are sequential events, which show maturation in the development of fetuses, which is the basis for life after birth," lead author Nadja Reissland, of the Department of Psychology at Durham University, said in a press release. "The findings could provide more information about when babies are ready to engage with their environment, especially if born prematurely."
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Reissland and her team conducted a total of 60 scans of 15 healthy fetuses at monthly intervals between 24-36 weeks of gestation.
During the earlier part of that developmental period, fetuses frequently touched the upper part and sides of their heads.
As time went on, the fetuses began to increasingly touch the lower, more sensitive, part of their faces, including their mouths.
At 36 weeks of gestation, a significantly higher proportion of fetuses were observed opening their mouths before touching them. This suggests, according to the researchers, that later in pregnancy the fetuses were able to anticipate that their hands were about to touch their mouths, rather than reacting to the touch of their hands.
"Increased touching of the lower part of the face and mouth in fetuses could be an indicator of brain development necessary for healthy development, including preparedness for social interaction, self-soothing and feeding," Reissland explained.
This is also likely the origin of thumb or finger sucking, done to promote calmness.
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The sequence of events appears to have been programmed into us, via genetics, as part of the growth process.
As co-author Brian Francis, Professor of Social Statistics at Lancaster, said: "This effect is likely to be evolutionarily determined, preparing the child for life outside the womb."
He continued, "Building on these findings, future research could lead to more understanding about how the child is prepared prenatally for life, including their ability to engage with their social environment, regulate stimulation and being ready to take a breast or bottle."
Premature babies miss some of the later developmental stages in the womb, giving them a much harder start in life.
Prior studies have found that unborn babies yawn in the womb. They also practice facial expressions there, thought to be in preparation for communicating after birth.
(Image: Nadja Reissland, Durham University)