On Sat, 20 Jan 2001, Joanne Gallivan wrote:
> My Sensation & Perception class asked a couple of questions I could
> (at best) only speculate about. Can anyone help?
>
> Here they are:
>
> 1) for sounds with frequencies above the human sensitivity range, are
> the ear structures still able to vibrate or not? That is, is our
> inability to 'hear' them due to the sensorineural or the conductive
> aspects? Related to this, can super-high frequency waves damege
> hearing?
>
> 2) How high are the frequencies that other mammalian species can
> detect?
>
> 3) What are the frequency ranges used in ultrasound technology?
>
(1) is an interesting question, but I have no idea if anyone has
attempted to answer it. (3) seems deceptively simple,
unless I don't understand. "Ultrasound" must be sound above human
hearing, which is usually given as 18K hz to 20K hz. So
ultrasound devices must use frequencies above these values.
But (2) drove me crazy, because I was sure I had some information
on it, but where? I went through every file and every text I
had--physiological psychology, perception, ethology, animal
behaviour--without finding it. I also went through two editions
of Kalat (twice!) because that was where I was sure it was. It
wasn't.
The source is S.S. Stevens' popular Time-Life book _Sound and
Hearing_, way back in 1965. On p. 194, it contains a beautiful
graph comparing the range of sounds produced by various musical
instruments and various animals, plus a similar graph (except no
musical instruments!) for auditory reception. The origin of the
data is unidentified, although it might appear in one of the
sources listed at the end of the book. Since it was S.S. Stevens
and many other eminent individuals listed as responsible for the
content of the book, although aimed at a popular audience, I'm
included to accept the data.
Some data from it (in Hz):
emission reception
horse 320-3,040
bat 10,000-120,000 1,000-120,000
grassshopper 7,000-1000,000 100-15,000
man 85 -1,100 20-20,000
dog 452-1,080 15-50,000
cat 760-1,520 60,65,000
lion 110-1,076
porpoise 7,000-120,000 150-150,000
moth 3,000-150,000
The text notes that "most animals can hear a much larger segment
of the frequency spectrum than they can produce. That is, they
make no sounds they cannot hear...an exception is the
grasshopper" [because it produces its sound mechanically, by
rubbing its legs]
BTW, it seems to have a misprint as well, because it says that
these are under ideal conditions, and than "actually, few human
adults can ordinarily hear tones much above 8,000 cycles". I'm
sure they meant 18,000.
Whew! I'm relieved I was able to dig it up, for my own sanity and
peace of mind.
-Stephen
------------------------------------------------------------------------
Stephen Black, Ph.D. tel: (819) 822-9600 ext 2470
Department of Psychology fax: (819) 822-9661
Bishop's University e-mail: [EMAIL PROTECTED]
Lennoxville, QC
J1M 1Z7
Canada Department web page at http://www.ubishops.ca/ccc/div/soc/psy
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