Are judgements of circularity local or global?
Related Experiment Videos
R F Hess1, Y Z Wang, S C Dakin
1McGill Vision Research, Department of Ophthalmology, McGill University, Montreal, Québec, Canada. rhess@bradman.vision.mcgill.ca
Abstract:
We assessed, in a task where subjects had to detect smooth deviations from circularity, whether the underlying mechanisms were localised in space to the size of the individual perturbations or whether they computed global shape. By manipulating the phase, the number of cycles of modulation and the spatial arrangement of the perturbations we argue that although either aspect can be detected, performance is ultimately limited by a global shape detecting mechanism. We show that this global mechanism receives input from spatially coarse, crossed orientationally tuned filters whose peak position in orientation depends on the overall shape to be detected.
Related Concept Videos
Woodward–Hoffmann Selection Rules and Microscopic Reversibility
Circular Orbits and Critical Velocity for Satellites
Nicolaus Copernicus (1473-1543) first suggested that the Earth and all other planets orbit the Sun in...
Dynamics Of Circular Motion: Applications
Green’s Theorem
Vector Forms of Green’s Theorem
Dynamics of Circular Motion
Any acceleration must be produced by some force. Therefore, any force or combination of forces can cause centripetal acceleration. A few examples include the tension in the rope on a...