Washington,
Sep 8 - Babies
develop facial expressions such as parting lips, wrinkling a nose or lowering a
brow much before they are born, a new study has shown.
And as the foetus grows, these facial motions
become increasingly complex, found the study by researchers at the University of Durham
in the UK.
While it was known that foetuses could form
expressions while in the womb, this new study tracked facial movements over
time, LiveScience reported.
By capturing images of two foetuses
periodically from 24 to about 35 weeks of gestation, the Durham team watched individual, unrelated
movements progress to complex combinations, associated with recognisable facial
expressions.
ÒWhat we have found for the first time is you
can look at the progression of the complexity of the movements,Ó lead study
author Nadja Reissland said.
In addition to tracking 19 total facial
movements, the researchers focused on sets of movements associated with two
expressions, one associated with crying, the other laughing.
Over time,
the movements associated with these began to appear in more complex
combinations.
For the study, appeared in the journal PLoS
ONE, the researchers used 4-D ultrasound images, which resemble video, to track
the facial motions of two female foetuses.
At 24 weeks, foetuses were more likely to make
a single movement, like a widening of the lips for example, all by itself.
Then, as the weeks passed, they began combining the movements, putting, say, a
lip widening movement with a nose wrinkle.
By about 35 weeks,
combinations of three and four movements associated with the two expressions
had surpassed single or double movements. A similar trend occurred when the
researchers looked at all 19 movements.
Reissland
pointed out that these facial movements don't mean the foetuses were
experiencing emotion.
ÒWe can see the expressions which we can
recognise; we can't say whether the foetus has emotion,Ó she said. ÒThey
(don't) have yet the cognition necessary to have the emotions.Ó Rather, these
motions are likely a form of practice, as the foetuses prepare to enter the
social world, where they must form bonds with others, she said.
Foetuses also suck their thumbs in the womb
and make breathing motions, both precursors for important activities once they
are born, she added.
The researchers are now
planning to look for other foetal facial expressions associated with anger,
smiling and sadness.
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