The scope and limits of reasoning practices in behavioral genetics

Abstract

Although philosophers have engaged with human behavioral genetics and the epistemic role model organisms play in research, little attention has been paid to human behavioral genetics research performed in model organisms. My dissertation, “The Scope and Limits of Reasoning Practices in Behavioral Genetics”, investigates the conceptual and ethical issues that arise when viewing human behavioral genetics in light of behavioral genetics performed in non-human organisms. Chapter 1 motivates the project, arguing that if we accept that non-human model organisms can provide experimental traction for research in human contexts then the same strategy ought to apply to behavioral genetics. Accepting this claim opens new domains of inquiry about behavioral genetics, both practically and philosophically. Chapter 2 examines what counts as a behavioral trait for the purpose of scientific investigation. I develop a cluster of criteria that are neither necessary nor sufficient but provide a reasonable framework for the scientific investigation of behavioral traits. As a result, a basis for normative evaluations emerges that rules some things in (e.g., learning and memory in fruit flies) and other things out (e.g., educational attainment in humans), with attendant consequences for different social and behavioral sciences. In chapter 3, I develop the concept of methodological shortfall from other existing explanations of science behaving counterintuitively. Methodological shortfall occurs when research communities concentrate their research programs around research questions, but their available methods are constrained in their ability to answer these questions unambiguously. In other words, a research community’s reach exceeds its grasp. I use contemporary behavioral genetics as a case study to demonstrate how the concept of methodological shortfall can help us make sense of ongoing complaints about behavioral genetics research undertaken on humans. Analyzing these issues through the lens of methodological shortfall reveals two paths forward for human behavioral genetics research: (1) continuing to use observational studies like Genome Wide Association Studies (GWAS) and Twin Studies, pursuing incremental improvements such as increased sample sizes, or (2) adopting experimental methodologies that can only be used in model organisms, which means approaching their object of study in an indirect way. After characterizing these two paths, I journey down each one to highlight how that choice impacts epistemic progress. Some researchers in behavioral genetics have chosen to work with model organisms to overcome the methodological barriers inherent in observational studies. I show how their work has generated epistemic progress on central research questions that have not been achieved by those working with human populations. I close with some observations about how the concept of methodological shortfall can contribute to broader discussions within philosophy of science. Chapter 4 directly addresses the question of the limits of reasoning practices in behavioral genetics, especially regarding claims that it can help create a more just society. I concentrate my argument on the epistemic merits of the proposed use of behavioral genetics in the context of education. I leverage analyses from my previous chapters to identify two necessary conditions that behavioral genetics would need to meet before the bioethics community could reevaluate whether it should be used to address social inequality. I then consider if a future field of behavioral genetics, one that has implemented these conditions, would have anything to offer. I leave open the possibility that the field may one day have something to contribute toward efforts to mitigate social inequality but highlight the potential harms of discrimination that are currently left unaddressed and may be exacerbated if behavioral genetics is deployed in the interim.