On Mon, 18 Dec 2000, Stephen Black wrote:
> But it's still an interesting question to ask whether external
> sound can affect fetal movement. The fetus can hear in the last
> trimester of pregnancy. This was demonstrated in an experiment
> (Birnholz & Benacerraf, 1983) involving the application of a loud
> "vibroacoustic device" to the pregnant woman's abdomen and
> observing fetal blink responses, and by an fMRI study (Hykin et
> al, 1999) showing that the fetal auditory cortex lights up to a
> nursery rhyme played loudly to the mother's abdomen.
>
I realize that the discussion is revolving around externally-generated
sounds, but I thought I'd comment on Stephen's statement that "the fetus
can hear in the last trimester of pregnancy." It can do even better than
that. In a fascinating experiment, Decasper and Spence (1986) found
that if mom had read "The Cat in the Hat" (vs. "The King, the Mice, and
the Cheese"; I think I have the stories right) starting around 34 weeks in
the pregnancy, neonates preferred that story to the one she
hadn't read. Here's the abstract:
DeCasper,-Anthony-J.; Spence,-Melanie-J.
Infant-Behavior-and-Development. 1986 Apr-Jun; Vol 9(2): 133-150.
Hypothesized that newborns would prefer the acoustic properties of a
particular speech passage if their mothers repeatedly recited that passage
while they were pregnant. 33 healthy pregnant women recited a particular
speech passage aloud each day during their last 6 wks of pregnancy. 16 of
their newborns were tested with an operant-choice procedure to determine
whether the sounds of the recited passage were more reinforcing than the
sounds of a novel passage. The previously recited passage was more
reinforcing. The reinforcing value of the 2 passages did not differ for a
matched group of control Ss. Results indicate that 3rd-trimester fetuses
experienced their mothers' speech sounds and that prenatal auditory
experience can influence postnatal auditory preferences. Noninvasive,
ethically acceptable methods to further study the effects of prenatal
auditory stimulation on postnatal auditory function and development are
suggested.
-----
Of course I don't think anyone is suggesting that newborns understand the
content, but fetuses are clearly able to recognize patterns in what they
hear.
Jeff
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Jeff Bartel
http://www-personal.ksu.edu/~jbartel
Department of Psychology, Kansas State University
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