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Abstract:
Abstract: Purpose: The vestibular system is known to measure
accelerations for linear forward movements. Can humans integrate
these vestibular signals to derive reliably distance and velocity
estimates? Methods: Blindfolded naive volunteers participated in a
psychophysical experiment using a Stewart-Platform motion
simulator. The vestibular stimuli consisted of Gaussian-shaped
translatory velocity profiles with a duration of less than 4
seconds. The full two-factorial design covered 6 peak accelerations
above threshold and 5 distances up to 25cm with 4 repetitions. In
three separate blocks, the subjects were asked to verbally judge on
a scale from 1 to 100 traveled distance, maximum velocity and
maximum acceleration. Results: Subjects perceived distance,
velocity and acceleration quite consistently, but with systematic
errors. The distance estimates showed a linear scaling towards the
mean and were independent of accelerations. The correlation of
perceived and real velocity was linear and showed no systematic
influence of distances or accelerations. High accelerations were
drastically underestimated and accelerations close to threshold
were overestimated, showing a logarithmic dependency. Conclusions:
Despite the fact that the vestibular system measures acceleration
only, one can derive peak velocity and traveled distance from it.
Interestingly, even though maximum acceleration was perceived non
linear, velocity and distance was judged consistently
linear.
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