ABSTRACT
Induced visual motion is the name assigned to a group of phenomena which can be described with more or less the same words: “illusory motion of stationary contours opposite the direction of moving ones”. As Dr. Howard has pointed out, it is possible that oculocentric, headcentric and exocentric mechanisms generate experiences which may be described by the words “induced visual motion”. We have found Dr. Howard’s framework very helpful in organizing our thoughts about the multiple sources of these apparently similar phenomena. We also accept that some forms of induced visual motion may depend on vection and cannot be explained by suppression of nystagmus (e.g., phenomenal tilt of a stationary stimulus during roll vection induced by a contoured disc rotating in a frontal plane). We are less certain than Dr. Howard, however, that there is only one mechanism for induced visual motion.
