Eidetic images, on the other hand, can be triggered by what appears to be simple visual inspection of a physical object. No overloading of the retinal tissues appears to occur, since the visual study of the object usually lasts several minutes and eye movements are continuous during the process. Often, it appears to be in the same physical space independent of eye movements. Eidetic imagery is generally reputed to exist in a significant percentage of children between the ages of seven and fourteen. The topic fell out of favor with the advent of behaviorism.
Eidetic imagery tends to disappear with age and is very rare among adults.
Eidetic images are usually generated spontaneously in children and by choice in adults. Maintaining an eidetic image, in either case, requires both interest and effort on the part of the subject. Despite this, eidetic images appear to fade in most cases at rates that are not fully controllable by the subject. It is therefore a judgment call as to whether to list eidetic images as under conscious control or not.