Cookies on this website
We use cookies to ensure that we give you the best experience on our website. If you click 'Continue' we will assume that you are happy to receive all cookies and you will not see this message again. Click 'Find out more' for information on how to change your cookie settings.

Evidence is presented that two distinct effects are generated when a sine-wave grating is temporally modulated. These effects may differentiated on the grounds of different responses with different forms of temporal modulation (drift or phase reversal), different behaviour with changes of visual eccentricity and with changes of contrast. One effect is roughly equivalent to spatial-frequency doubling, as described by Kelly. The other is seen as a fractional increase in apparent spatial frequency ie 1.2 X 1.4 X the original. Earlier papers are reviewed to lend support to these conclusions. The results obtained for spatial-frequency doubling are consistent with Kelly's model of a nonlinearity followed by a temporal integration. Spatial-frequency doubling emerges under conditions where a fractional increase in apparent spatial frequency would generally be expected but the particular spatiotemporal conditions are such that a breakdown in the motion-correspondence process may be suspected. Reasons for the existence of fractional shifts are not entirely clear, but it is argued that the similarity of the shifts induced by various manipulations (decreases of luminance, decreases of contrast, temporal modulation) are such that a general explanation must be sought, rather than one specific to temporal modulation alone.

Type

Journal article

Journal

Perception

Publication Date

1983

Volume

12

Pages

663 - 682

Keywords

Adult, Discrimination Learning, Female, Form Perception, Humans, Male, Pattern Recognition, Visual, Psychophysics, Space Perception, Visual Fields