Similarly, the ability of the child to selectively attend to other than spoken language displays implies a cognitive goal, and a means of determining when the goal has been achieved. The goal may be fairly simple, such as scanning a figure to produce a recognition response, or fairly complex, such as following a conversation in a crowded room. However, regardless of complexity, it is necessary that the child be able to focus attention to limited aspects of the information in SIS, and to ignore or filter out task-irrelevant information. Thus, the efficient, goal-oriented processing of information from SIS requires the ability to ignore non-task-relevant information, as well as the selective processes mentioned above.

Inasmuch as listening and looking are simply names for attending to structural information in the auditory or visual modality, they exhibit the developmental trends described by E. Gibson (1969) and discussed earlier. There are, however, two other aspects of attention which should be noted. One is the distinction between the focus and margin of attention (Blumenthal, 1972); the other is the concept of automaticity of information processing (La Berge and Samuels, 1973).

Attending to informational displays may be considered as analogous to searching a display with a spotlight. The point of focus of the spotlight is bright and clear, while the area surrounding the spot of light fades from brightness to dimness to darkness. The bright spot represents the focus of attention, while the dim area represents the margin of attention. In attending to one aspect of an internal display, we are also vaguely aware of non-attended information in the margin of consciousness or awareness. Blumenthal (1972) characterizes differences between information processing in the two components of attention: