The Effect of Social Desirability and Social Approval on Self-Reports of Physical Activity

As with many other human behaviors, self-reporting of physical activity is subject to many sources of error and bias. Existing physical activity assessments capture no more than 50 percent of the variance in free-living physical activity levels, and often much less (1). However, because of the efficiency and utility of this approach, self-reports of physical activity are commonly employed in most large-scale epidemiologic studies. Certain personality traits may affect self-reporting of physical activity. The traits of “social desirability” and “social approval” have been found to influence participants’ reports of diet (2–5). “Social desirability” is the defensive tendency of individuals to portray themselves in keeping with perceived cultural norms, whereas “social approval” is the need to obtain a positive response in a testing situation (4). It has been found that people, especially women, who score higher on the social desirability scale are more likely to underreport their fat and total energy intake (2–5). To extend our understanding of systematic errors in self-reports of physical activity, we designed the present investigation to compare three self-reported physical activity assessment approaches commonly used in epidemiologic and clinical studies with objective measures of physical activity and to test for systematic errors that can be ascribed to social desirability and social approval. Our objective criterion measures were physical activity energy expenditure estimated from doubly labeled water and estimated resting energy expenditure, as well as intensity-specific activity duration derived by means of the ActiGraph accelerometer (Manufacturing Technology, Inc., Fort Walton Beach, Florida).