most sensitive sense in humans?
marvit at psych.upenn.edu
Wed Oct 6 13:30:46 EST 1999
[[ What's the most sensitive sense? ]]
While this is a fun question for cocktail party chatter, there are
actually at least two ways of answering it empirically.
1) Weber fraction. That is, the smallest just detectable difference (jnd)
along some parameter of a stimulus divided by the magnitude of the base
stimulus. With this measure, hearing (with its frequency differences)
may be a candidate at 0.1% or better. Smell (at least intensity
differences) is something like 30-40%. This is a way of characterizing
the organismic (system) sensitivity.
2) Absolute detection of stimuli by a single receptor. As someone
previously mentioned, the rods in the retina will react to a single
photon. However, olfactory cells will also react to a single
molecule. Hair cells (in hearing and vestibular system) have a
threshold that is just slightly above the Brownian motion of the
surrounding fluid. This is a way of characterizing the mechanistic
(underlying neural/receptor) sensitivity.
Have fun testing!
: Dr. Peter Marvit <marvit at psych.upenn.edu>, Psychology Dept, Univ. of Penn :
: 3815 Walnut St., Philadelphia, PA 19104 w:215/898-3460 fax:215/898-3460 :
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