Humans have an extremely flexible ability to categorize regularities in their environment, in part because of attentional systems that allow them to focus on important perceptual information. In formal theories of categorization, attention is typically modeled with weights that selectively bias the processing of stimulus features. These theories…

This paper reports on a study concerned with rapid mental operations of the central processor as it performs tasks such as the comparison of rotated figures, mental arithmetic, sentence verification, and memory scanning. The central processor is the site of most of the symbol manipulation that takes place in the human information processing…

The question of whether pupil diameter indicates information processing load during reading was investigated in three experiments involving 24 college students reading passages of varying difficulty. A TV camera and monitor, together with a video-recorder, were used to measure the diameter of the pupil under a reading condition and under three…