ABSTRACT
There have been many theories about perception and many visual experiments. Most conclude that perception is instantaneous and not subject to extended judgement. It is an active exploration rather than a passive recording of the visual elements in the field of view and is selective and personal. It is not a simple mechanical process and the eye/brain can often be misled by a visual stimulus. The physiologist E.H. Weber established that a constant change in physical sensation like brightness or sound level becomes less noticeable if the brightness or sound levels increase at a constant rate. The brightness of an object must increase logarithmically for the eye to judge that change of brightness is increasing in equal increments. The same logarithmic scale applies to the ear’s response to changes in sound level (see The nature of sound, page 186).
