Although empirical investigations strongly support the use of motivational interviewing (MI), there is no theory to clearly explain how or why MI works. The authors propose that MI is efficacious because it mobilizes clients' inherent resources for motivation, learning, creativity, problem solving, and goal-driven activity. Examining MI from a client agency perspective reveals new ways of conceptualizing several critical issues, including MI's fundamental "spirit," the function of resolving ambivalence, the importance of change talk, MI's ability to combine well with other approaches, and the success of brief MI interventions. Implications for the science and practice of MI are discussed from the standpoint that clients are primarily responsible for driving therapeutic gains.

Previous research indicates that brief motivational interventions for college student drinkers may be less effective in group settings than individual settings. Social psychological theories about counterproductive group dynamics may partially explain this finding. The present study examined potential problems with group motivational interventions by comparing outcomes from a standard group motivational intervention (SGMI; n = 25), an enhanced group motivational intervention (EGMI; n = 27) designed to suppress counterproductive processes, and a no intervention control (n = 23). SGMI and EGMI participants reported disruptive group dynamics as evidenced by low elaboration likelihood, production blocking, and social loafing, though the level of disturbance was significantly lower for EGMI individuals (p = .001). Despite counteracting group dynamics in the EGMI condition, participants in the two interventions were statistically similar in post-intervention problem recognition and future drinking intentions. The results raise concerns over implementing individually-based interventions in group settings without making necessary adjustments.