Background Reading on Behavioral Genetics

The author discusses how the availability of genetic modification services may affect social equality. People have different standards of normality, excellence, and well-being. While some may value traits like stamina and strength, others may value certain thinking abilities. It is difficult to create a universal standard for equality. The author suggests that we should strive towards a genetic "decent minimum" because it is not ethically, conceptually, or politically feasible to equalize people's natural assets against fluctuating social standards and values. The author poses no objection to enhancement technologies but rather to the possible ways in which selective access might deepen economic, moral, and social inequalities.

Geneticists must be careful not to overstate their research findings because many behaviors are both biologically and socially produced. When reporting research findings, scientists must be aware of the social power that their "scientific results" carry. As scientists strive to understand the genetic basis for behavior, we need to ask whether research questions are framing behavior as variations of normality or in terms of mental illness.

The author claims that fruitless is the first gene to have been identified as necessary and sufficient for determining a higher-level organism's complex behavior. He also speculates about whether such findings may be applicable to humans and help us understand human sexual orientation. While acknowledging that human behavior is extremely complex and subject to cultural factors, he notes that one or a few genes may also possibly determine the instinctive components of human sexuality.

Ehrlich and Feldman take on the reductionist claims of evolutionary psychology and behavioral genetics in a critique of the many assumptions embedded in these fields. Behavioral genetics has also misunderstood the relationship between genes and behavior through its use of twin studies that show the heritability of behavior. Scientists misinterpret statistical correlation, conflating it with the forces of genetic causation when in fact scientists have no idea how some set of genes might actually produce the behaviors being studied.The authors suggest that we shift our focus of attention from genes to plastic brains that are shaped by culture in the production of human behavior.

In several recent court cases, criminal defendants have brought behavioral genetics testimony to bear on their crimes, arguing that their criminal acts can be explained not as a result of "bad character" but as a result of "bad genes." The use of such evidence has been hampered by the difficulty of establishing a reliable claim about specific genetic traits affecting behavior. Court use of behavioral genetics evidence depends upon the strength of the link between genetic explanation and behavioral outcome. As scientists develop more precise explanations of genetic contributors like MAOA and SLC6A4 to behavior, the strength of behavioral genetic claims in the criminal court system will strengthen and likely become more useful to both defendants and prosecutors.

Although there is a strong genetic basis for most psychiatric disorders, the underlying genes have for the most part not been identified due to the small sample sizes and dense genotypes used in research. Some new studies seek to overcome these problems by using a larger number of psychiatric cases and more controls. One day these large samples may be fully assayed for thousands of genetic polymorphisms using chip-based detection. Even as we consider these future possibilities, the field has learned much about the interaction between genes and psychiatric disorders. For the most part, diseases will not be accounted for by genetic loci that have major gene effects. Also, genes rarely act in isolation so we should not expect to find single genes to explain psychiatric disorders. Some genes like modifier genes will be important to account for, but at the same time, many of the disease-causing alleles discovered will have a low frequency and not make significant contributions to disorders being studied. Rare alleles will more likely be implicated in disorders if they have a large effect size than rare alleles with small effect sizes. Basic science will benefit much from a more nuanced understanding of the genetic contributions to psychiatric disorders. Clinical medicine will benefit if study designs can be modeled to account for the great genetic complexity of these disorders.

The biological model in which specific genes cause particular behaviors is an oversimplified way for thinking about the complex interactions among genes, the brain, and the environment that more likely result in the realization of human behavior. Studies like Hariri et al (2002) and Caspi et al (2002) suggest that genes alone do not directly regulate behavior but rather that the regulation of gene expression by environmental variables affects behavior via the conduit of the brain. For studies of complex behaviors that involve many genes, the development of technologies like microarray analysis will become crucial.

Although we may take the phrase, "a gene for", for granted as a necessary dimension of "gene talk," this paper carefully evaluates the conceptual framework posed by this phrase and whether it is adequate to talk about "a gene for" psychiatric illnesses. Much evidence suggests that single genes are not implicated in complex psychiatric disorders but rather multiple genes that interact together in complex ways and with environmental factors. There is much contingency of psychiatric disorders upon factors other than genes and so the causal mechanisms of disease are not straightforward. The author explains that the role of genes in psychiatry will probably be best explained at a level that is not the same as the level of the very disorders themselves.

This article argues that social considerations do not displace the methodological principles of science but incorporate themselves into the day-to-day work of scientific investigators. The very project of scientific observation is social in that it involves negotiation among and within interested parties. Certainly sensory observation is important to data collection, but in the actual process of knowledge production, organized bodies of investigators determine what is meaningful. Also, the practice of scientific reasoning only happens in regard to considerations that are deemed relevant by a particular group. There is no total truth claim that can be made because all perspectives cannot be accounted for in any project of scientific reasoning. Although the partiality of knowledge means that grand theories of truth are problematic, it also suggests that more local claims to truth possess merit and robustness as a result of their specificity.

This article argues for the heritability of behavioral dispositions although specific genes have not yet been identified for complex behaviors like intelligence and anxiety. The authors believe that further research in molecular genetics holds the promise of drawing upon current behavioral-genetic leads to achieve real progress in identifying behaviorally relevant genes. They make a careful point to emphasize that they are arguing for the heritability of behavior and not for genetic determinism.

Researchers within the discipline of behavioral genetics risk perpetuating ideas about racial inferiority by glossing over the social inequalities that cause some communities to perform poorly on the sorts of IQ tests that are important to studies of behaviors like intelligence. We must consider as a society how we are going to understand human agency and also determine whether genetic studies of personality will allow for greater individual freedom by relieving individuals of responsibility for their actions or whether such studies will hold individuals to be more accountable because of the genetic essentiality of their behavior. Understanding the genetic influences on complex behavioral traits is challenging because several genes must be considered that interact with various environmental factors over a gradient of time. An approach to studying complex traits has been for behavioral geneticists to identify endophenotypes, which are the component dimensions of complex behaviors.

Drawing upon concepts of social constructionism and medicalization, the author discusses the importance of applying a critical perspective to genetic studies of behavior that take culturally produced categories to be natural and that reify pathological classifications, socially inscribed by the gaze of medicine. The social constructionist perspective applies a critical lens to categories and facts that have been made to appear as inevitable aspects of a universal nature. Medicalization refers to the processes by which medical discourses have come to scrutinize and discipline aspects of people's everyday lives like food consumption and use of leisure time. This phenomenon can be dangerous by taking social categories and understandings and reifying them as genetically defined aspects of human behavior. Reductionist projects to understand complex behaviors can lose sight of the ways in which human cognition and self-reflection impact life choices.

Sternberg argues that intelligence does have certain universal dimensions but that these universal dimensions become meaningful through culture. Currently there is no neutral assessment of intelligence that can be applied to all cultures that have their own ways of thinking and their own values about what it means to be intelligent. The goal of researchers should be to locate intelligence tests in their culturally specific contexts rather than generalizing across populations.

This article discusses the future possibility of preventative policing of criminals in light of the Caspi study which showed a relationship between criminality and one's combination of MAOA gene expression and history of maltreatment. The implication of the Caspi study is that the facility for an individual to adopt a life of non-violence has a genetic component which may potentially be screened by the State in the future. The author argues that information from genetic testing must only be used to interpret past events in an individual's life and not to make predictions about future behavior. This stance is part of an "equality approach" that assumes that no child will be violent.