Why does Motivational Interviewing work?

While in Ireland last month for the MI forum Bill Miller gave a talk on “MI and Social Dominance.” He begged the question “why does MI work at all? How is it that a relatively brief conversation can trigger change in behavior that has sometimes persisted for decades?”

He offered an explanation by Bill Neto, an Australian psychologist – that how MI influences behavior may lie in our evolutionary past.  “When faced with a dominance challenge, an individual may counter-attack, yield or withdraw…and these behavioral routines serve to promote survival of a species.”

He went on to say that “when directed or advised what to do, exerting the freedom not to comply signals a higher position in social dominance while submission represents subservience.”  Because our clients are the ultimate decision makers in their behavior, being noncompliant is a simple way to exert their freedom.

In contrast, Neto describes MI as “adaptively significant, signaling to an individual that they are social-hierarchically and physically safe, allowing the human cortex to process information and engage in decision-making.”  Since MI is person-centered it is practiced with empathy, collaborative partnership and accepting each person’s autonomy. This spirit allows clients to visibly relax within the first few minutes of a conversation, thus promoting conversation that can lead to change talk and subsequent behavior change.

There are now over 800 controlled clinical interventions involving MI in some way, including examples of its use as a brief effective treatment.  Since MI is still in its early infancy there is no exact answer about why it works.

We may not know for years the exact answer to this question but we do know MI works by its evoking quality to each individual about what it is that makes them successful. That quality may be the wisdom in MI – giving each person the autonomy of what it is they want, what helps them with behavior change, and affirming them in their individual journeys towards change.