Human Biological and Psychological Diversity

Evolutionary Psychology and Normal Science: in Search of a Unifying Research Program

Why are there so many controversies in evolutionary psychology? Using a couple of concepts from philosophy of science, this paper argues that evolutionary psychology has not reached the stage of mature, normal science, since it does not currently have a unifying research program that guides individual scientists working in the discipline. The argument goes against claims made by certain proponents and opponents of evolutionary psychology, and it is supported by discussion of several examples. The paper notes that just because evolutionary psychology has not reached the stage of normal science, the discipline is nevertheless a source of many progressive theoretical developments and interesting empirical discoveries.

No support for the hereditarian hypothesis of the Black-White achievement gap using polygenic scores and tests for divergent selection

OBJECTIVES

Debate about the cause of IQ score gaps between Black and White populations has persisted within genetics, anthropology, and psychology. Recently, authors claimed polygenic scores provide evidence that a significant portion of differences in cognitive performance between Black and White populations are caused by genetic differences due to natural selection, the "hereditarian hypothesis." This study aims to show conceptual and methodological flaws of past studies supporting the hereditarian hypothesis.

MATERIALS AND METHODS

Polygenic scores for educational attainment were constructed for African and European samples of the 1000 Genomes Project. Evidence for selection was evaluated using an excess variance test. Education associated variants were further evaluated for signals of selection by testing for excess genetic differentiation (F_st ). Expected mean difference in IQ for populations was calculated under a neutral evolutionary scenario and contrasted to hereditarian claims.

RESULTS

Tests for selection using polygenic scores failed to find evidence of natural selection when the less biased within-family GWAS effect sizes were used. Tests for selection using F_st values did not find evidence of natural selection. Expected mean difference in IQ was substantially smaller than postulated by hereditarians, even under unrealistic assumptions that overestimate genetic contribution.

CONCLUSION

Given these results, hereditarian claims are not supported in the least. Cognitive performance does not appear to have been under diversifying selection in Europeans and Africans. In the absence of diversifying selection, the best case estimate for genetic contributions to group differences in cognitive performance is substantially smaller than hereditarians claim and is consistent with genetic differences contributing little to the Black-White gap.

The Fallacy of Equating the Hereditarian Hypothesis with Racism

There is a large amount of evidence that groups differ in average cognitive ability. The hereditarian hypothesis states that these differences are partly or substantially explained by genetics. Despite being a positive claim about the world, this hypothesis is frequently equated with racism, and scholars who defend it are frequently denounced as racists. Yet equating the hereditarian hypothesis with racism is a logical fallacy. The present article identifies ten common arguments for why the hereditarian hypothesis is racist and demonstrates that each one is fallacious. The article concludes that society will be better served if the hereditarian hypothesis is treated the same way as any other scientific claim—critically, but dispassionately.

Are Whites and minorities more similar than different? Testing the cultural similarities hypothesis on psychopathology with a second-order meta-analysis

The cultural differences hypothesis is the assertion that there are large differences between Whites and racial/ethnic minorities in the United States, while there are small differences between- (e.g., African Americans and Latinos) and within- (e.g., Latinos: Mexican Americans and Cuban Americans) minority groups. Conversely, the cultural similarities hypothesis argues that there are small differences between Whites and minorities, and these differences are equal or smaller in magnitude than differences between and within minorities. In this study, we conducted a second-order meta-analysis focused on psychopathology, to (a) test these hypotheses by estimating the absolute average difference between Whites and minorities, as well as between and within minorities, on levels of psychopathology, and (b) determine if general and meta-analytic method moderators account for these differences. A systematic search in PsycINFO, Web of Science, and ProQuest Dissertations identified 16 meta-analyses (13% unpublished) on 493 primary studies (N = 3,036,749). Differences between Whites and minorities (d+ = 0.23, 95% confidence interval [0.18, 0.28]), and between minorities (d+ = 0.30, 95% confidence interval [0.12, 0.48]) were small in magnitude. White–minority differences remained small across moderators. These findings support the cultural similarities hypothesis. We discuss their implications and future research directions.

How Universal Is the General Factor of Personality? An Analysis of the Big Five in Forager Farmers of the Bolivian Amazon

In various personality models, such as the Big Five, a consistent higher order general factor of personality (GFP) can be identified. One view in the literature is that the GFP reflects general social effectiveness. Most GFP studies, however, have been conducted in Western, educated, industrialized, and rich democracies (WEIRD). Therefore, to address the question of the universality of the GFP, we test whether the GFP can also be identified in a preliterate indigenous sample of Tsimane by using self-reports, spouse reports, and interviewer ratings. In the Tsimane, a viable GFP could be identified and the intercorrelations between personality traits were significantly stronger than in samples from industrial countries. The GFP correlated with the ratings of social engagement. In addition, self and spouse ratings of the GFP overlapped. Overall, the findings are in line with the notion that the GFP is a human universal and a substantive personality factor reflecting social effectiveness.

Race Research and the Ethics of Belief

On most accounts, beliefs are supposed to fit the world rather than change it. But believing can have social consequences, since the beliefs we form underwrite our actions and impact our character. Because our beliefs affect how we live our lives and how we treat other people, it is surprising how little attention is usually given to the moral status of believing apart from its epistemic justification. In what follows, I develop a version of the harm principle that applies to beliefs as well as actions. In doing so, I challenge the often exaggerated distinction between forming beliefs and acting on them.¹ After developing this view, I consider what it might imply about controversial research the goal of which is to yield true beliefs but the outcome of which might include negative social consequences. In particular, I focus on the implications of research into biological differences between racial groups.