According to the text the most widely studied psycho-social need is the need for "achievement".
Need for achievement alludes to a person's want for noteworthy achievement, mastering of aptitudes, control, or exclusive expectations. The term was first utilized by Henry Murray and related with a scope of activities. These include: "extreme, drawn out and rehashed endeavors to achieve something troublesome. To work with singleness of reason towards a high and far off objective. To have the assurance to win". The idea of Need for achievement was hence promoted by the psychologist David McClelland.