In industry, human factors (also known as ergonomics) is the study of how humans behave physically and psychologically in relation to particular environments, products, or services. Many large manufacturing companies have a Human Factors department or hire a consulting firm to study how any major new product will be accepted by the users that it is designed for. A human factors specialist typically has an advanced academic degree in Psychology or has special training. The term usability is now sometimes used as an alternative to human factors, although human factors is really a larger area of study, including responses that are unrelated to usability, such as reactions and preferences in relation to visual and other sensory stimuli.
In a typical human factors or usability study, a group of hired or volunteer test subjects that represent future end users is given tasks to do with a working prototype or early version of a product. Typically, a test subject is observed while doing a task, asked to react verbally as any problems occur or as observations are made, and interviewed after each test. (Test subjects have to be assured that it is the product - and not their own skills or capabilities - that is being tested.) Usually, the test is videotaped for later study. In some cases, successive corrections to the product are made during the course of testing.
Human factors study can focus on general human behavior in relation to technology (such as studies of how people react to various type styles and sizes), on a generic type of product (such as wearable computers), on specific environment or product designs as a whole, or on some specific design aspects of a particular environment or product. Depending on objectives, the result of human factors study can include suggestions on how to redesign the object of study or a general guideline for designing such an object.
In addition to relatively formal human factors study, human factors can be said to be underway any time a designer thinks about the effects of the design on the end user, and, in fact, much corrective design work goes on without formal testing. A relatively new object of study is the design of a Web site, either as a general problem or in order to build a specific Web site that meets user needs.