Examining the Role of Body Image Instability in Young Adult Women: Conceptualization, Development, and Psychometric Evaluation of the Vacillating Body Image Scale (VBIS).

The current study conceptualized body image instability as a maladaptive tendency to vacillate between different self-perceptions of one's overall body image and developed a corresponding measure to assess body image instability. Results from a series of studies of young adult women demonstrated the validity, reliability, and utility of the Vacillating Body Image Scale (VBIS) as a meaningful measure of body image instability. In Study 1, we found that body image instability, as assessed by the VBIS, represents a unidimensional and reliable construct. In Study 2, we found evidence for both the convergent and discriminant validity of the VBIS in relation to other individual differences measures (i.e., self-concept schema, broad personality factors). In Study 3, the concurrent criterion validity of the VBIS was supported for young adult women in relation to a range of adjustment measures. Finally, in Study 4, we found consistent evidence for the incremental validity of the VBIS in predicting subsequent variations in eating disturbances, even after controlling for global self-esteem and self-concept instability. Overall, our findings offer promising support for our contention that body image instability, as measured by the VBIS, represents an important construct for understanding eating-related disturbances and other health outcomes in young adult women.