A professional practitioner is a specialist who encounters certain types of situations again and again. This is suggested by the way in which professionals use the word “case” or project, account, commission, or deal, depending on the profession. All such terms denote the units which make up a practice, and they denote types of family resembling examples. Thus a physician may encounter many different “cases of measles”; a lawyer, many different “cases of libel.” As a practitioner experiences many variations of a small number of types of cases, he is able to “practice” his practice. He develops a repertoire of expectations, images, and techniques. He learns what to look for and how to respond to what he finds. As long as his practice is stable, in the sense that it brings him the same types of cases, he becomes less and less subject to surprise. His knowing-in-practice tends to become increasingly tacit, spontaneous, and automatic, thereby conferring upon him and his clients the benefits of specialization.
On the other hand, professional specialization can have negative effects. In the individual, a high degree of specialization can lead to a parochial narrowness of vision. When a profession divides into subspecialties, it can break apart an earlier wholeness of experience and understanding. Thus people sometimes yearn for the general practitioner of earlier days who is thought to have concerned himself with the “whole patient,” and they sometimes accuse contemporary specialists of treating particular illnesses in isolation from the rest of the patient’s life experience. Further, as a practice becomes more repetitive and routine, and as knowing-in-practice becomes increasingly tacit and spontaneous, the practitioner may miss important opportunities to think about what he is doing. He may find that he is drawn into patterns of error which he cannot correct. And if he learns, as often happens, to be selectively inattentive to phenomena that do not fit the categories of his knowing-in-action, then he may suffer from boredom or “burn-out” and afflict his clients with the consequences of his narrowness and rigidity. When this happens, the practitioner has “overlearned” what he knows.
A practitioner’s reflection can serve as a corrective to overlearning. Through reflection, he can surface and criticize the tacit understandings that have grown up around the repetitive experiences of a specialized practice, and can make new sense of the situations of uncertainty or uniqueness which he may allow himself to experience […]
When the phenomenon at hand eludes the ordinary categories of knowledge-in-practice, presenting itself as unique or unstable, the practitioner may surface and criticize his initial understanding of the phenomenon, construct a new description of it, and test the new description by an on-the-spot experiment. Sometimes he arrives at a new theory of the phenomenon by articulating a feeling he has about it.
When he finds himself stuck in a problematic situation which he cannot readily convert to a manageable problem, he may construct a new way of setting the problem – a new frame which, in what I shall call a “frame experiment,” he tries to impose on the situation.
When he is confronted with demands that seem incompatible or inconsistent, he may respond by reflecting on the appreciations which he and others have brought to the situation. Conscious of a dilemma, he may attribute it to the way in which he has set his problem, or even to the way in which he has framed his role. He may then find a way of integrating, or choosing among, the values at stake in the situation.
(Schön, 1995, p. 6of & 62f)