Zwillingsstudien in der Verhaltensforschung und Kultur / Gesellschaft

Ein Artikel von Turkheimer zur Verhaltensforschung, der auch das Zusammenspiel von Natur und Gesellschaft behandelt:

Zunächst relativ generell:

The presence of genetic influences does not mean that genes “cause” behavior in any preordained way. Rather, it means that genes predispose toward some (tacit or active) ongoing series of individual behavioral choices. These choices have effects on later circumstances that affect later options for genetically influenced behavioral choices, and so on. This causal chain is captured in the behavior-genetic literature through the concept of gene–environment correlation, or genetically influenced differences in environmental exposure. Gene–environment correlation may be passive, active, or evocative (Plomin, De-Fries, McClearn, & McGuffin, 2008). It is passive when, for example, children receive both genes influencing antisocial behavior and abusive treatment from their parents and model the behavior they receive. It is active when people genetically inclined to be social seek social groups in which to participate and avoid spending long periods of time alone. It is evocative when children with genetically influenced difficulties with emotional control throw temper tantrums that generate angry responses from their parents. Gene–environment correlation is described in the developmental psychopathology literature as social selection, in which the association between risk and outcome reflects origin of risk in the individual rather than the effects of risk. For example, poverty may be a risk factor for schizophrenia because people at genetic risk for schizophrenia tend to drift into poverty because of inability to maintain educational and occupational performance, as well as because poverty provides the disease-triggering stress. In the epidemiological literature, gene–environment correlation is described as reverse causation or confounding, in which some to all of the association between an experience and an outcome reflects the effects of people on their environments rather than the effects of their environments on them.

Eine interessante Darstellung, aus der man sehen kann, wie sich die beiden Faktoren gegenseitig beeinflussen können und wie schnell auch  biologische Ursachen mit sozialen Ursachen verwechselt werden können.

Die Zusammenfassung dort finde ich auch noch ganz interessant:

The discovery that all behavior is partially heritable transformed psychology, but, ironically, it also transformed behavior genetics. Once we accept that basically everything—not only schizophrenia and intelligence, but also marital status and television watching—is heritable, it becomes clear that specific estimates of heritability are not very important. The omnipresence of genetic influences does not demonstrate that behavior is “less psychological” or “more biologically determined” than had originally been thought; rather it shows that behavior arises from factors intrinsic as well as extrinsic to the individual. The real implications of heritability lie not in questions of relative biological determinism but in revealing the need to understand both the mechanisms through which the individual, whether consciously or not, directs his or her own life course and his or her power to do so. In psychology, where it is not ethically possible to conduct randomized experiments on life outcomes, the natural experiment provided by the twin study can be most helpful in addressing these issues.

Er hat in dem Bericht einige interessante Beispiele für Zwillingsstudien. Lesenswert.