Interattribute apparent motion.

Apparent motion can be seen between two alternating stimuli even if they are defined with respect to their background by attributes other than luminance (such as color, or texture). We measured motion strength as the maximum separation between two alternating stimuli which produced an impression of motion, for conditions in which the two stimuli were defined by the same attribute (intra-attribute) as well as conditions in which they were defined by different attributes (interattribute). The attributes used to define the stimuli were luminance, color, texture, relative motion, or stereopsis. The results indicate that motion was seen for all the intra-attribute conditions about equally well. The results also show that interattribute motion could be seen for all combinations studied. The motion strength in these cases was about 80% of that for the intra-attribute conditions. The process responsible for this motion perception must therefore be able to combine information from different attributes.