The first question is what the fetus can hear of such musical
selections. This depends upon a number of factors including
sensitivity of the auditory system, the baseline noise intensity
in the body, the extent to which the musical signal is filtered
by the mother's body, and the intensity (loudness) of the
original signal.
Robert Abrams and Kenneth Gerhardt at the Univerity of Florida
have summarized what is known about the acoustic environment of
the fetus in several publications. It appears that sounds below
60 Hz are unlikely to be heard because the internal noise is
around 80 dB at such low frequencies. The mother's body
filters frequencies above 500 Hz such that they are unlikely to
be heard unless the original music was played at a very high
intensity (over 100 dB). Thus there is only a narrow range
(from about 60 Hz to 250 Hz, i.e. Middle C and 2 octaves below
on the piano) that a fetus is likely to hear of the outside
world. The intensity of these sounds would need to be above 80
dB.
The fetus is unlikely to hear much more than a few of the
fundamental frequencies of the lower notes of a musical
selection.
References
Abrams, R M, & Gerhardt, K J (2000). The acoustic environment
and physiological responses of the fetus. J. of Perinatology,
20, 31-36.
Abrams, R M, & Gerhardt K J (1997). Some aspects of the foetal
sound environment. In I Deliege and J Sloboda (Ed.) Perception
and Cognition of Music. UK: Psychology Press.
Ken
----------------------
Kenneth M. Steele, Ph.D. [EMAIL PROTECTED]
Associate Professor
Dept. of Psychology
Appalachian State University
Boone, NC 28608
USA
