Core Mechanisms of Change in Motivational Interviewing

This experiment used a dismantling approach to examine change mechanisms in motivational interviewing (MI). Seventy-two undergraduate participants who scored in the top 35th percentile on trait anger were randomly assigned to: full MI (FMI), spirit-only MI (SOMI), or psychoeducation. They met individually with an experimenter for one 30- to 45-minute session to discuss their anger. In the FMI condition, the relational and technical elements of MI were both used to elicit change talk. In the SOMI condition, the supportive and relational elements of MI were emphasized. In the psychoeducation condition, the focus was placed on teaching the components of anger episodes. Participants were then asked to launch a daily, online, deep breathing exercise during the following week. Results showed that participants in both MI conditions emitted more change talk than those in the psychoeducation condition. Independent session ratings showed that despite the attempted elimination of technical elements in the SOMI condition, the FMI and SOMI conditions did not differ on the experimenter’s acceptance, empathy, direction, autonomy support, and collaboration. Also, results did not support the main effect on program launches. These results indicate it is challenging to separate relational from technical elements in MI and, thus, to identify core mechanisms of change.