Why is Intelligence Negatively Associated with Religiousness?

Do conservatives really have an advantage in mental health? An examination of measurement invariance

Many studies have found that conservatives show an advantage in mental health and happiness and various causes of this have been debated (e.g., religiousness, ideology, or genetics). However, not much attention has been given to examining whether this advantage is psychometrically real, or whether it is due to test bias. We analyzed data from two large Finnish surveys of adults (Ns = 848 and 4,978) from Lahtinen (2024), that measured general anxiety and depression symptoms, as well as a new wokeness scale. Using differential item functioning tests, we found no evidence for measurement bias in these scales. The correlation between index scores of wokeness and mental health (internalizing) was -0.36, which increased to -0.41 when measurement error was removed. The association between wokeness and anxiety (r = -0.33, adjusted r = 0.37) was stronger than wokeness and depression (r = 0.20, adjusted r = 0.22).

The Relationship Between Religiousness/Spirituality and Psychometric Intelligence in the United States

An inverse relationship between religiousness/spirituality (R/S) and psychometric intelligence (IQ) is well-documented in previous literature. However, the studies that have examined group differences on IQ regarding R/S have limited generalizability. The present study contributed to the literature by evaluating IQ among participants identifying as differentially religious/spiritual (i.e., religious only, spiritual only, both religious and spiritual, or neither religious nor spiritual) and among those classified as either Christian/Catholic, Atheist, or Agnostic. Four hundred and thirty-two participants (M age = 37.9; 36% men) participated online via Amazon's Mechanical Turk as part of a larger study and completed a brief measure of IQ, a scale of religiousness and spirituality, and a demographics questionnaire. Correlations between IQ and self-reported religiousness/spirituality were small and negative (Mean r = -0.17), consistent with previous literature. Multivariate analyses of covariance (MANCOVAs) controlling for age, gender, education, and socioeconomic status (operationalized by estimated annual household income) indicated that IQ scores tended to be lowest (p < 0.001) for "religious only" participants (estimated marginal mean [EMM] = 93.0) and highest for "neither religious nor spiritual" participants (EMM = 103.7). Furthermore, IQ scores were significantly lower (ps < 0.001) for Christian/Catholic participants (EMM = 96.7) compared to both Atheist (EMM = 104.9) and Agnostic participants (EMM = 107.5). Discussion of these findings, relationships to previous theoretical and empirical work, limitations of the present study, and directions for future inquiry are provided.

The Negative Religiousness-IQ Nexus is a Jensen Effect on Individual-Level Data: A Refutation of Dutton et al.'s 'The Myth of the Stupid Believer'

A recent study by Dutton et al. (J Relig Health 59:1567-1579. https://doi.org/10.1007/s10943-019-00926-3 , 2020) found that the religiousness-IQ nexus is not on g when comparing different groups with various degrees of religiosity and the non-religious. It suggested, accordingly, that the nexus related to the relationship between specialized analytic abilities on the IQ test and autism traits, with the latter predicting atheism. The study was limited by the fact that it was on group-level data, it used only one measure of religiosity that measure may have been confounded by the social element to church membership and it involved relatively few items via which a Jensen effect could be calculated. Here, we test whether the religiousness-IQ nexus is on g with individual-level data using archival data from the Vietnam Experience Study, in which 4462 US veterans were subjected to detailed psychological tests. We used multiple measures of religiosity-which we factor-analysed to a religion-factor-and a large number of items. We found, contrary to the findings of Dutton et al. (2020), that the IQ differences with regard to whether or not subjects believed in God are indeed a Jensen effect. We also uncovered a number of anomalies, which we explore.

The Interplay Between Cognitive Intelligence, Ability Emotional Intelligence, and Religiosity

The negative association between cognitive intelligence (CI) and religiosity has been widely studied and is now well documented. In contrast, the role of emotional intelligence (EI) in this context has been poorly investigated thus far. Some available data indicate that EI, unlike CI, correlates positively with religiosity. To date, however, no study has explored the relationship between religiosity and both intelligences simultaneously. In current studies (Ns = 301 and 200), we examined the interplay between all three constructs. The results showed that CI was positively correlated with ability EI and negatively with some measures of religiosity. EI, on the other hand, revealed no direct, significant relationship with religiosity. However, when combined into a single regression model with CI, EI became a significant positive predictor of religiosity. Moreover, Study 2 revealed that the link between EI and religiosity was mediated by empathy. Interestingly, we also found a reciprocal suppression between CI and EI, since both predictors increased their influence on religiosity when analyzed together. Although the suppression was present in both studies, it was observed for different religiosity measures in each case, indicating that this effect is probably dependent on various factors, such as sample structure or type of religiosity.

The Myth of the Stupid Believer: The Negative Religiousness-IQ Nexus is Not on General Intelligence (g) and is Likely a Product of the Relations Between IQ and Autism Spectrum Traits

Numerous studies have found a negative relationship between religiousness and IQ. It is in the region of - 0.2, according to meta-analyses. The reasons for this relationship are, however, unknown. It has been suggested that higher intelligence leads to greater attraction to science, or that it helps to override evolved cognitive dispositions such as for religiousness. Either way, such explanations assume that the religion-IQ nexus is on general intelligence (g), rather than some subset of specialized cognitive abilities. In other words, they assume it is a Jensen effect. Two large datasets comparing groups with different levels of religiousness show that their IQ differences are not on g and must, therefore, be attributed to specialized abilities. An analysis of the specialized abilities on which the religious and non-religious groups differ reveals no clear pattern. We cautiously suggest that this may be explicable in terms of autism spectrum disorder traits among people with high IQ scores, because such traits are negatively associated with religiousness.

The Negative Intelligence-Religiosity Relation: New and Confirming Evidence

Zuckerman et al. (2013) conducted a meta-analysis of 63 studies that showed a negative intelligence-religiosity relation (IRR). As more studies have become available and because some of Zuckerman et al.'s (2013) conclusions have been challenged, we conducted a new meta-analysis with an updated data set of 83 studies. Confirming previous conclusions, the new analysis showed that the correlation between intelligence and religious beliefs in college and noncollege samples ranged from -.20 to -.23. There was no support for mediation of the IRR by education but there was support for partial mediation by analytic cognitive style. Thus, one possible interpretation for the IRR is that intelligent people are more likely to use analytic style (i.e., approach problems more rationally). An alternative (and less interesting) reason for the mediation is that tests of both intelligence and analytic style assess cognitive ability. Additional empirical and theoretical work is needed to resolve this issue.