Examining the "traditional background hypothesis" for the MMPI-2-RF L-r scores in a muslim faith-based sample

The traditional background hypothesis (TBH) is a long-standing belief associated with the Minnesota Multiphasic Personality Inventory (MMPI) L scale; a validity scale, which appears on every version of the family of MMPI instruments including the soon-to-be released MMPI-3. The L scale was originally designed to assess whether test respondents presented themselves in an unrealistically favorable light. Both researchers and clinicians noted, however, that those from traditional Christian faith-based groups produced elevated L-scale scores. A recent meta-analysis supported this observation, reporting an average L-scale elevation 0.50 SD greater than the MMPI-2 normative sample compared to samples of those with presumptively strong Christian-Judeo faith. Some limitations of this meta-analysis are that (a) the samples used in it included those undergoing an evaluative assessment, which could elevate L-scale scores independent of strength of faith belief, and (b) direct assessments of strength of faith or positive impression management were not included or measured independently. Our primary goal in this study was to examine the TBH addressing these limitations with a sample of those who self-identified as believers in the Muslim faith (N = 267), the examination of which expands the scope beyond those of the Christian-Judeo faith. Consistent with previous results, the mean L-r (MMPI/MMPI-2 L scale counterpart on the MMPI-2-Restructured Form) was 56.41 T. Higher L-r scale scores were associated with increasing strength in the Muslim faith, and although increasing L-r scores were primarily associated with impression management, increasing Muslim-based faith values had a nontrivial influence on L-r scores and especially in the moderate score range of this scale.