A study on human behavior has revealed that 90% of the population can be classified into four basic personality types: Optimistic, Pessimistic, Trusting and Envious. However, the latter of the four types, Envious, is the most common, with 30% compared to 20% for each of the other groups. This is one of the main conclusions of a study recently published in the journal, Science Advances by researchers from Universidad Carlos III de Madrid, together with colleagues from the universities of Barcelona, Rovira i Virgili and Zaragoza. The study analyzed the responses of 541 volunteers to hundreds of social dilemmas, with options leading to collaboration or conflict with others, based on individual or collective interests. The research results shed light in relation to what moves the collective or individual interest in the processes of negotiation, and as such, it is useful for the management of business, organizations or for political reformulation.