This article examines eight “gaps” in order to clarify why the quantitative genetics methods of partitioning variation of a trait into heritability and other components has very limited power to show anything clear and useful about genetic and environmental influences, especially for human behaviors and other traits. The first two gaps should be kept open; the others should be bridged or the difficulty of doing so should be acknowledged: 1. Key terms have multiple meanings that are distinct; 2. Statistical patterns (...) are distinct from measurable underlying factors; 3. Translation from statistical analyses to hypotheses about measurable factors is difficult; 4. Predictions based on extrapolations from existing patterns of variation may not match outcomes; 5. The partitioning of variation in human studies does not reliably estimate the intended quantities; 6. Translation from statistical analyses to hypotheses about the measurable factors is even more difficult in light of the possible heterogeneity of underlying genetic or environmental factors; 7. Many steps lie between the analysis of observed traits and interventions based on well-founded claims about the causal influence of genetic or environmental factors; 8. Explanation of variation within groups does not translate to explanation of differences among groups. At the start, I engage readers’ attention with three puzzles that have not been resolved by past debates. The puzzles concern generational increases in IQ test scores, the possibility of underlying heterogeneity, and the translation of methods from selective breeding into human genetics. After discussing the gaps, I present each puzzle in a new light and point to several new puzzles that invite attention from analysts of variation in quantitative genetics and in social science more generally. The article’s critical perspectives on agricultural, laboratory, and human heritability studies are intended to elicit further contributions from readers across the fields of history, philosophy, sociology, and politics of biology and in the sciences. (shrink)

The article explores some of the issues that have arisen in the discourse on pharmaceutical cognitive enhancement (PCE), that is, the use of stimulant drugs such as methylphenidate, amphetamine and modafinil by healthy individuals of various populations with the aim of improving cognitive performance. Specifically, we explore the presumed sizes of existing PCE user populations and the policy actions that have been proposed regarding the trend of PCE. We begin with an introductory examination of the academic stances and philosophical issues (...) involved in defining PCE. We then focus on an examination of the population sizes of presumed current PCE users that have been listed in the academic literature on PCE, on presuppositions, which have been problematized by some authors as based on anecdotal or misinterpreted survey data. We follow this with an empirical examination of a potential PCE user population in a national context (students at the University of Ljubljana in Slovenia). We then proceed to examine the regulatory options proposed in the academic literature to address PCE, finally comparing them with an empirical overview of the policy recommendations on PCE produced in the multinational context of several national ethics advisory bodies (EABs) in Europe. Our main conclusion is that there is still little debate among the national EABs on what type of public policy responses, if any, are needed to address PCE in European countries, and that the issues they do address are similar to those discussed and proposed in the academic articles on PCE. (shrink)

The paper suggests an application of the precautionary principle to the use of genetics in psychiatry focusing on scientific uncertainty. Different levels of uncertainty are taken into consideration—from the acknowledgement that the genetic paradigm is only one of the possible ways to explain psychiatric disorders, via the difficulties related to the diagnostic path and genetic methods, to the value of the results of studies carried out in this field. Considering those uncertainties, some measures for the use of genetics in psychiatry (...) are suggested. Some of those measures are related to the conceptual limits of the genetic paradigm; others are related to present knowledge and should be re-evaluated. (shrink)

Despite the long history of scientific, philosophical, and political debate around heritability studies, certain fundamental conceptual issues have not been recognized or well appreciated. The starting point is that heritability does not measure the degree of influence that genes have on a trait or provide a reliable basis for choosing which traits to investigate further with molecular genetic research. The short argument on this point revolves around two issues: the disconnect between analyzing measurements of a trait and exposing the measurable (...) genetic and environmental factors underlying the trait’s development; and the possibility of heterogeneity in these underlying factors, that is, different factors may lead to the same trait value. The idea of underlying heterogeneity is elaborated through schematic diagrams and distinguished from other senses of heterogeneity. Five conceptually distinct approaches for addressing underlying heterogeneity are identified, corresponding to distinct ways of managing the reciprocal relationship between the degree of knowledge of the dynamics through which the trait develops and the actions that can be reliably be based on what is known . This framework, which extends the interventionist notion of causality, allows the scope and limitations of heritability studies to be clarified in greater detail. It can also inform critical appreciation of newer methods of analysis of genetic and environmental factors. The issues discussed in this article do not centre on empirical data or technical detail and should be accessible to non-specialists as well as challenging active researchers. (shrink)

The vision of legendary criminologist Cesare Lombroso to use scientific theories of individual causes of crime as a basis for screening and prevention programmes targeting individuals at risk for future criminal behaviour has resurfaced, following advances in genetics, neuroscience and psychiatric epidemiology. This article analyses this idea and maps its ethical implications from a public health ethical standpoint. Twenty-seven variants of the new Lombrosian vision of forensic screening and prevention are distinguished, and some scientific and technical limitations are noted. Some (...) lures, biases and structural factors, making the application of the Lombrosian idea likely in spite of weak evidence are pointed out and noted as a specific type of ethical aspect. Many classic and complex ethical challenges for health screening programmes are shown to apply to the identified variants and the choice between them, albeit with peculiar and often provoking variations. These variations are shown to actualize an underlying theoretical conundrum in need of further study, pertaining to the relationship between public health ethics and the ethics and values of criminal law policy. (shrink)

The idea of individual responsibility for action is central to our conception of what it is to be a person. Behavioural genetic research may seem to call into question the idea of individual responsibility with possible implications for the criminal justice system. These implications will depend on the understandings of the various agencies and professional groups involved in responding to violent and anti-social behaviour, and, the result of negotiations between them over resulting practice. The paper considers two kinds of approaches (...) to the question of responsibility and ‘criminal genes’ arising from a sociological and philosophical perspective respectively. One is to consider the social context and possible practical implications of research into ‘criminal genes’ which will later be examined through interviews and discussions with a range of experts including lawyers and social workers. A second and different kind of approach is to ask whether the findings of behavioural genetics ought to have implications for attributions of responsibility. Issues of genetic influence are central to both approaches. (shrink)