The process of learning in which the learner assumes primary responsibility for planning, implementing, and evaluating a learning project. The learner chooses what to learn and how to learn, and also decides when to continue and when to end the learning project.
By studying these individuals, the researcher can "isolate the influence of the formal teaching environments on learning and thus permit the adult to be studied when he/she learns in a naturalistic and spontaneous fashion." (Danis & Tremblay)
Mezirow: “…there is probably no such thing as a self-directed learner, except in the sense that there is a learner who can participate fully and freely in the dialogue through which we test our interests and perspectives against those of others and accordingly modify them and our learning goals.”