Laboratoire Psychologie de la Perception Institut Neurosciences Cognition Université Paris Descartes Centre National de Recherche Scientifique
Home
Research
vision Vision
action Action
speech Speech
avoc AVoC
support support staff
People
Former Staff
Teaching
Publications
Ethics
Events
Practical

Calendar
Opportunities
Internships
Contracts
Platforms
Links

Baby Lab

Intranet
Position displacement, not velocity, is the cue to motion detections of second-order stimuli.

Explored the detection of 1st-order (luminance-based) and various 2nd-order (texture- and stereo-based) motion using a procedure to dissociate the target's velocity and position provided by K. Nakayama and C. W. Tyler (1981). In Exp 1, 6 observers viewed annular gratings oscillating in rotational motion at various rates. For 1st-order motion, these motion detection thresholds decreased with increasing temporal frequency and were determined by a minimum velocity. Motion detection thresholds for 2nd-order motion remained roughly constant across temporal frequency. In Exp 2, luminance-based gratings of different contrasts were tested to show that the velocity-dependence was not an artifact of pattern visibility. In Exps 3 and 4, results similar to Exp 1 were obtained with a central presentation of a linear grating, instead of an annular grating, and with a motion discrimination rather than motion detection task. It is concluded that, within the ranges tested here, 2nd-order motion is more readily detected with a mechanism which tracks the change of position of features over time. (PsycINFO Database Record (c) 2007 APA, all rights reserved)



PDF Link