Does Internal or External Locus of Control Have a Stronger Link to Mental and Physical Health?

Abstract

When examining the relationship of locus of control (LOC) with mental and physical health, internal and external loci of control have typically been defined as a single, bipolar construct, despite prior evidence that the two are orthogonal. Across three cross-sectional studies, we hypothesized that internal and external locus of control would each predict unique variance in well-being. Study 1 examined the association of LOC with psychological well-being, Study 2 examined the association between LOC and physical well-being, and Study 3 examined the association of three types of LOC with psychological, subjective, and physical well-being. Study 3 also employed three types of LOC assessments. In all three studies (n = 1181 for Study 1, n = 577 for Study 2, n = 271 for Study 3), undergraduate participants completed self-report surveys through an online data-collection system. Through a series of regression analyses, the results showed that external LOC was a more consistent predictor of well-being than Internal LOC. More specifically, perceived constraints (a form of external LOC) were the strongest LOC predictor over all other types. This suggests that internal and external LOC should be measured as two separate constructs, and that external LOC is more strongly associated with well-being than internal LOC.