INVESTIGADORES
MARTIN Andres
congresos y reuniones científicas
Título:
Apparent Size Biases The Perception Of Speed In Rotational Motion
Autor/es:
MARTÍN, A.; CHAMBEAUD, J. G.; BARRAZA, J. F.
Lugar:
Florida, USA
Reunión:
Congreso; 10th Annual Meeting, Vision Science Society; 2010
Resumen:
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Velocity
constancy is the ability to equate physical speeds of objects placed
at different depths, despite objects angular speeds on the retina
changes proportionally with depth. Multiple studies have shown that
size cues play a central role in the achievement of velocity
constancy. On the other hand, some studies have provided evidence
showing that depth cues are unnecessary for velocity constancy.
However, since retinal size is linearly related to depth, it is
reasonable to hypothesize that both cues should affect the perception
of speed. We present here results of two experiments in which we
measure the bias of perceived speed and size as a function of depth
for rotational motion. We use this type of motion to avoid the effect
of the frame on the perceived speed since the reference in rotational
motion is its own center. We introduce binocular disparity to produce
depth perception. The stimulus consisted of 16 dots (0.15 deg size)
located 2 deg away from the center of rotation, undergoing rotational
motion. 6 observers, the authors and 3 others naives as to the
purpose of this study took part in the experiment. Results show that
observers overestimate dot speed and pattern size of further stimuli
but perceiving angular velocity as invariant. This result shows that
the visual system would re-scale dot speed when the apparent radius
increases so as to maintain angular velocity constant. However, the
bias in perceived size is much larger than that of speed, which
suggests that such re-scaling is not linear.