Over the last two decades the concepts of "human factors" and "nontechnical skills", which describe the interaction of physical, psychological, cognitive and social characteristics of people with their environment and which have a significant influence on safe patient care, have become established in anesthesiology. Nevertheless, findings from the social sciences and safety research, particularly with respect to understanding human factors and the development and prevention of incidents, have so far only been partially accepted in medicine. In particular, the contribution of people is often problematized in the sense of a "risk factor". In the first of two articles, the theoretical foundations of nontechnical skills are explained and an awareness of the fact that it is not human deficiencies but rather normal, evolutionarily sensible thought processes and social practices of the people involved that are responsible for adverse events is created.