Cognitive processes surely exist, so it can hardly be unscientific to study them. - Ulric Neisser

Attention is not a mysterious concentration of psychic energy; it is simply an allotment of analyzing mechanisms to a limited region of the field. To pay attention to a figure is to make certain analyses of, or certain constructions in, the corresponding part of the icon.

The fact that the span of apprehension averages only four or five... probably results from the high rate of encoding. In a tachistoscopic experiment the subject must read the fading icon as rapidly as possible.

The term "cognition" refers to all processes by which the sensory input is transformed, reduced, elaborated, stored, recovered, and used. It is concerned with these processes even when they operate in the absence of relevant stimulation, as in images and hallucinations. Such terms as sensation, perception, imagery, retention, recall, problem-solving, and thinking, among others, refer to hypothetical stages or aspects of cognition.