In 1992, C. Wickens describes a qualitative model of human information processing that incorporates stages which are used to perceive sensations, transform data and choose action. Each stage takes certain time to perform. Time taken for each stage may be extended due to additional considerations (e.g. uncertainty). According to this model attentional resources are finite in nature. Choices on how to distribute or allocate attentional resources have significant implications for workload assessment and work design.

According to this model, receptors help to transduce stimuli into neural signals which are transferred to brain for further processing of information through perceptual and cognitive process. Details of perceptual and cognitive process; and, role of different memory have already discussed in previous paragraphs. Schematic diagram of human information processing is presented in Figure 3.

Figure 3. Information processing model (Adapted from Wickens, 1992)