Reason 1: Development Focuses on the Machine or System

During design and development of the product, the emphasis and focus may have been on the machine or system, not on the person who is the ultimate end user. The general model of human performance shown in Figure 1-1 helps to clarify this point.

There are three major components to consider in any type of human performance situation as shown in Bailey's Human performance model.

■ The human

■ The context

■ The activity

Because the development of a system or product is an attempt to improve human performance in some area, designers should consider these three components during the design process. All three affect the final outcome of how well humans ultimately perform. Unfortunately, of these three components, designers, engineers, and programmers have traditionally placed the greatest emphasis on the activity component, and much less emphasis on the human and the context components. The relationship of the three components to

each other has also been neglected. There are several explanations for this unbalanced approach:
There has been an underlying assumption that because humans are so inherently flexible and adaptable, it is easier to let them adapt themselves to the machine, rather than vice versa.
Developers traditionally have been more comfortable working with the seemingly "black and white," scientific, concrete issues associated with systems, than with the more gray, muddled, ambiguous issues associated with human beings.
Developers have historically been hired and rewarded not for theater, personal, "people" skills but for their ability to solve techmcal proble
The most important factor leading to the neglect of human needs has been that in the past, designers were developing products for end users who were much like themselves. There was simply no reason to study
such a familiar colleague. That leads us to the next point.