Using short vignettes to disentangle perceived capability from motivation: a test using walking and resistance training behaviors

Self-efficacy is arguably the strongest correlate of physical activity, yet some researchers suggest this is because the construct confounds ability with motivation. We examine a more circumscribed construct, called perceived capability (PC), meant to measure ability but not motivation and propose that the construct will not be related to unskilled physical activities but may be linked to skilled behaviors. The purpose of this paper was to examine whether a PC construct can be stripped of motivation using a vignette approach in both walking and resistance training behaviors. Participants were a random sample of 248 university students, who were then randomly assigned to either answer resistance training or walking behavior questions. Both groups completed a PC measure and reasons for their answer before and after reading a vignette that clarified the phrasing of capability to a literal use of the term. PC was significantly (p < .01) higher post- compared to pre-vignette and the differences were greater (p < .01) for walking than for resistance training. PC had significantly (p < .01) smaller correlations with intention and self-reported behavior post-disambiguation, which resulted in a null relationship with walking but a small correlation with resistance training behavior. When PC was combined with intention to predict behavior, however, there was no significant (p > .05) difference in the amount of variance explained pre- to post-vignette. Thought listing showed that participants did not report capability barriers to walking and over half of the sample construed capability as motivation/other priorities pre-vignette. The findings support use of a vignette approach for researchers who wish to disentangle the assessment of PC from motivation while creating no overall loss in explained variance of physical activity.