A field experiment on stages of change for smoking cessation: the effects of matched and mismatched information Behaviour change can be described as a process in which people progress through several qualitatively different stages. Stage models predict that people in different stages need different types of information to progress to subsequent stages. In a field experiment we tested this assumption using the Social Cognitive Stage Model (SCSM).Smokers and ex-smokers in five stages received information in three information conditions: information developed to increase positive outcome expectations of quitting or information developed to decrease the positive outcome expectations of smoking or information developed to increase self-efficacy expectations.Two months after participants were provided with the information, the interaction between stage and information condition was significant. In addition, the matchmismatch test in which the matched conditions are compared with the mismatched conditions was also significant. After eight month, the overall match-mismatch test was still significant, although the expected effects within stages were present only in the precontemplation and in the action stage. Gender interacted significantly with matching: especially after eight months the matching effects were present only in men.The results provide scarce evidence on the validity of stage models in general and more specifically on the validity of the SCSM. In a sample that was very similar to staged samples studied before, we showed that people in different stages benefited from different types of information. This implicates that the stages differ qualitatively. In addition, while most descriptions of people in different stages are based on cross-sectional findings, these experimental data give a new perspective on the psychological characteristics of people in different stages.
InleidingDat gedragsverandering tijd kost, soms stokt en niet altijd over rozen gaat mag duidelijk zijn. Zo zijn mensen niet altijd gemotiveerd om te veranderen, blijven ze twijfelen of ze er wel goed aan doen, stellen verandering uit, doen niet wat ze zich hebben voorgenomen of vallen terug in het oude gedrag. De meeste modellen en theoriee¨n over gedragsverandering erkennen deze aspecten van gedragsverandering echter niet. Veranderingsfasemodellen doen dat wel. Veranderingsfasemodellen beschouwen gedragsverandering als een gefaseerd proces waarin mensen verschillende fasen doorlopen.