Diminished UV radiation enhances national cognitive ability, wealth, and institutions through health and education☆
Introduction
Lynn and Vanhanen, 2002, Lynn and Vanhanen, 2006 posited inherited intelligence as a proximate influence on the wealth of nations. Dark-skinned populations, who reside close to the equator, would be poorer than light-skinned ones, who reside close to the poles, owing to millenary evolutionary processes associated with adaptation to climatological and other environmental conditions which differentiated Homo sapiens intellectually at higher latitudes (Lynn, 2006). Consistent with economic development research, which dismisses geography as a causal variable and emphasizes institutions as determinants of national wealth (Nunn, 2009), Rindermann's cognitive capitalism disregards geography as a relevant force and places institutional strength as a mediator of cognitive ability's influence on nations' income, albeit specifying that cognitive ability is genetically and culturally determined (Rindermann, 2012, Rindermann and Thompson, 2011, Rindermann et al., 2012). Yet, evidence generated over the past few years has produced overwhelming evidence of close relationships existing between geographic and cognitive variables and suggests that it is national wealth that enhances national IQ rather than vice versa.
Complex cognitive ability (CCA), measured by IQ tests and/or standardized student evaluations of math, reading, and/or science (Rindermann, 2007), increases with distance from the equator across countries (Azam, 2017, León and Burga-León, 2015, Lynn and Vanhanen, 2012). The relationship is also significant across states, provinces, or regions within Italy, Japan, Peru, Russia, Spain, Sudan, and the United States, although not in India and Turkey (León & Hassall, 2017). A theory that CCA depends on UV radiation has been proposed considering that radiation decreases from the equator to the poles (León & Burga León, 2014). The theory not only accounts for the observed latitude-CCA correlations but has also generated evidence that populations residing in the western United States, where UV radiation is stronger, present lower cognitive ability than eastern USA populations (León, 2015); that high altitude above sea level, where UV radiation is greater, impairs CCA (León & Avilés, 2016); and that CCA decreases with proximity to the equator in the United States among White children, whose ancestors' skin evolved to grasp scarce UV photons at higher latitudes (Jablonski & Chaplin, 2010), but not among African Americans and Hispanics, whose skin melanin absorbs and dissipates light (León & Hassall, 2017).
This article builds upon the latter study. León and Hassall took into account that UV radiation causes cell oxidative stress (Meng, Zhang, Zhu, Wang, & Lei, 2009) and, through it, fatigue (Kennedy et al., 2005), possibly reducing industriousness cumulatively through age; since this personality aspect (DeYoung, Quilty, & Peterson, 2007) is relevant to the creation of wealth and poverty is known to affect cognitive functioning (e.g., Nisbett et al., 2012), the greater poverty closer to the equator would impair CCA. León and Hassall's (2017) explanation has been upheld by an unpublished study showing that a socioeconomic latent variable defined by wealth, education, and employment mediates the effects of UV radiation on CCA in Italy and, without employment, among White children in the United States (León, 2017).
There is a need for worldwide testing of cognitive capitalism's tenets vis-à-vis UV radiation theory. A number of international studies have upheld the postulates that CCA influences wealth through scientific-technological progress and the quality or strength of institutions (Christainsen, 2013, Coyle et al., 2015, Rindermann et al., 2015). Rindermann and Thompson (2011); Rindermann et al., 2012, Rindermann et al., 2015 presented structural equation models (SEMs) and saturated path models which supported cognitive capitalism's hypotheses worldwide, but only reported standardized root mean square residual (SRMR) and comparative fit index (CFI). Cognitive capitalism lacks evidence based on more demanding indicators of SEM adjustment, such as χ2, “the only substantive test of fit for SEM” (Barrett, 2007; p. 815), and root square error of approximation (RMSEA), one of the most informative fit indices and present in virtually all papers that use SEM. Therefore, we tested Hypothesis 1: CCA → institutional strength (IS) → wealth using such rigorous indicators of model fit, among others. Furthermore, León and Burga-León (2017), utilizing a multiracial sample in the United States, evaluated cognitive capitalism's CCA → wealth linkage in the context of UV radiation theory and reported a radiation → CCA → wealth SEM that emerged well-fitted in contrast with an unsatisfactory radiation → wealth → CCA one. In the present study, we tested the more specific Hypothesis 2: UV radiation → CCA → IS → wealth.
Since León's (2017) findings in Italy and among White children in the United States need replication between nations, we tested here Hypothesis 3: UV radiation → wealth + education → CCA → IS across countries. Moreover, Author's formulation admits alternatives. The free radicals associated with cell oxidative stress have been implicated in the pathology of several human diseases, including atherosclerosis, cancer, malaria, rheumatoid arthritis, and neurodegenerative diseases (Aruoma, 1998). Rate of disease has been shown to impair CCA (Daniele & Ostuni, 2013), assumedly because the immunological system competes for energy with the developing brain of the child (Eppig, Fincher, & Thornhill, 2011). Disease is also likely to cause desertion from school, impoverish educational achievements, and deteriorate worker productivity. Since health + education can be expected to mediate the effects of UV radiation on CCA, institutional strength, and wealth, the study tested Hypothesis 4: (UV radiation → health + education → wealth → IS) + (health + education → CCA → IS).
Section snippets
Countries
The countries or territories selected for the present study are those whose intelligence scores were derived from IQ test scores and/or scores from standardized student evaluations in Rindermann's (2007) standardization in 194 countries. That is, the study ignores the 66 countries or territories for which Rindermann estimated intelligence scores based on national indicators of school attendance. Of the 128 countries with intelligence measurements, 32 lacked UV radiation data. Table S1 in
Results
All the variables of the study were significantly intercorrelated (see Table S2). The SEM in Fig. 1A emerged with significant path coefficients between CCA, the institutional latent variable defined by the three observed institutional variables, and log income; like in the Rindermann studies, a satisfactory SRMR value emerged. However, the model presented inadequate χ2/df, CFI, and RMSEA indices. The results contradicted Hypothesis 2, too: addition of UV radiation to cognitive-capitalism's
Discussion
The study results have various implications. The first major finding exposed cognitive capitalism's empirical weakness. Judging by the RMSEA indicator of model fit, cognitive ability was unable to account for institutional strength and country wealth under any combination of variables tried, which reveals that the cognitive capitalism model is untenable under rigorous scrutiny. The finding not only is relevant to psychology. Since the high-impact Hall and Jones (1999) and Acemoglu, Johnson, and
Acknowledgments
The author appreciates access to the Andersen-Dalgaard-Selaya UV radiation data set provided by Pablo Selaya.
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The study data are available at http://dx.doi.org/10.6084/m9.figshare.5119765.