The HCD approach is based on the use of techniques that communicate and empathize with the people involved, gaining a deep understanding of their needs, desires, and experiences that often transcend what the people themselves accomplish.
Methods have been developed to improve product design through understanding and/or predicting human/product interaction (Stanton, 2014). For example, the development of contextual design techniques (Holtzblatt et al., 2004) facilitated the analysis, classification, and description of human-environment interactions. The increasing use of scenarios and personas has provided a basis for describing people and contexts (Carroll, 2000). The focus on emotional engagement during design (Chapman, 2005; Norman, 2005) has caused HCD methodologies to move away permanently from the initial engineering approach.
The methodologies available to designers today increase and develop significantly, sometimes borrowing methods from other fields, such as psychology or sociology. Methods can be classified according to their purpose or intended use: some allow for the collection of information about people (anthropometric, cognitive, emotional, sociological, or psychological data); others consist of techniques for interacting with people in order to facilitate the exploration of meanings, desires, and needs using both verbal and nonverbal techniques (an example is ethnographic interviews or focus groups); others involve the analysis of those mental processes that are not always directly accessible (e.g., body language analysis, direct observation, or facial expression analysis); finally, many methods rely on reflection and discussion to simulate insights, opportunities, and possible future scenarios (e.g., co-design or the use of working prototypes).