Figure 2.

Schematic framework for the relationship between attention and task performance. (A) Performance-resource functions, which show psychophysical performance for a given amount of allocated attention. Each curve describes this relationship for different types of discrimination tasks; some discrimination tasks require a lot of attentional resources (lower diagonal line), others require little (middle diagonal line) or no (top line) attentional resources. Note that each of the four corners in this plot depicts one of the quadrants in Table 1 (here A = attention, and C = consciousness). (B) Let us assume that when observers can consciously discriminate two stimuli at 75% correct, they are conscious of the difference to a certain degree. If we accept this, we can measure an attention threshold for a given aspect of visual attribute: how much attention is required to achieve a certain level of conscious discrimination. For example, the attentional threshold for natural scene discrimination (top line) is much lower than those for discriminating red/green bisected discs or rotated letters (bottom line).