What do we mean by pre-attentive attributes? To define this we’ll go back and first look at a few other terms that relate to the human brain. Iconic memory is a type of sensory memory that stores images for a fraction of a second. This type of perceptual processing is automatic and unconscious. That’s why it is called pre-attentive. Conscious higher-level processing, that occurs later, is called attentive processing. It is sequential, takes more time, and results in learning. Pre-attentive visual processing detects color and position of objects in 2-D space.

Colin Ware has organized pre-attentive attributes into four categories: form, color, spacial position, and motion. Form means length, width, orientation, shape, size, and enclosure. Color is hue and intensity. Hue is the precise term for which we normally think of as color such as red, yellow, and blue. Color is made up of three separate attributes. Hue is one, Intensity applies two the other two attributes of color: saturation and lightness.