Is the action-oriented solution instantiated in human nervous systems?
One especially promising line of evidence concerning whether efference copy based action-oriented representations are employed in human nervous systems comes from research on visual stability during saccadic eye movements. The phenomenon to be explained here is how it is that we dont perceive the world to be jumping around even though our eyes are constantly moving in the short jerky movements known as saccades. Helmholtz (1867) hypothesized that efference copies are used in the following manner. When the eye moves, there is a shift in the array of information transduced at the retina. When the eye movement is caused in the normal waythat is, by self-generated movements due to commands sent to ocular musclesan efference copy is used to compute the amount to compensate for the anticipated shift in the retinal image. The amount of movement estimated based on the character of the efference copy is thus used to offset the actual shift in retinal information giving rise, ultimately, to a pe
