et of images that are shifted from frame to frame. This is called apparent motion and as these shifting sequences are extended beyond two frames the motion percept becomes stronger. Edward Adelson (1991) provides a nice demonstration of how these shifting sequences can be conceived as spatio-temporal orientation by using a flipbook like you might find in a box of cracker-jacks. If you were to use an especially thick flipbook and slice through the middle of it you would see how the third dimension (representing time) extrudes the orientation of the image in the third dimension. Apparent motion is the same technique that is used to create movies, cartoons, and other video images. The changing spatio-temporal orientation is said to create motion energy. At the earliest stages of motion perception detectors specially sensitive to this motion energy are activated. The first such mechanisms proposed, called Reichardt detectors were described after studying the visual system of the fly. Reichardt detectors are tuned to direction and are inhibitory in nature, that is, when a detector is stimulated in its non-preferred direction it sends a signal to the next detector in the line that tells it to ignore the stimulus.Recent Research In the research studies discussed below random dot stimuli were used. A random dot stimulus is composed of a target or targets that use apparent motion to create a coherent motion percept. A single dot traveling in apparent motion in a consistent direction creates a trajectory percept or local motion information. Multiple dots traveling in apparent motion in a consistent similar direction will create a percept of coherent background motion or global flow information. In a random dot display, noise or distractor information, is created by using dots that travel inconsistently over time. This can be done by having the noise dots simply pop up in different places in each frame or by having the dots change the ...
