Einfluss der Eltern, der Gene bzw. der Peer-Group

Ich habe gerade Matt Ridley „Genome: The Autobiography of a Species in 23 Chapters“ durchgelesen und kann es empfehlen.


Im letzten Absatz fand ich die folgende Passage interessant (S. 304):

Besides we now know that virtually all the evidence purporting to show how parental influences shape our charakter is deeply flawed, Besides, we now know that all evidence purporting to show how parental influences shape our character is deeply flawed. There is indeed a correlation between abusing children and having been abused as a child, but it can be entirely accounted for by inherited personality traits. The children of abusers inherit their persecutor’s characteristics. Properly controlled for this effect, studies leave no room for nurture determinism at all. The step-children of abusers, for instance, do not become abusers. (…)

Hudith Rich Harris suddenly began questioning them a few years ago. What she discovered appalled her. Because virtually no studies had controlled for heritability, there was no proof of causation at all in any study. Not even lip service was being paid to this omission: correlation was routinely presented as causation. Yet in each case, from behaviour genetic studies, there was new, strong evidence against what Rich Harris called „The nurture assumption“. Studies of the divorce rate of twins, for exempel, reveal that genetics accounts for about half of the variation in divorce rate, non shared enviromental factors for another half and shard home environment for nothing at all. In other words, you are no more likely to divorce if reared in a brocken home than the average – unless your biological parents divorced. Studies of criminal records of adoptees in Denmark revealed a strong correlation with the criminal record of the biological parent and a very small correlation with the cirminal record of the adopting parent – and even that vanished when controlled for peer group effects, whereby the adopting parents were found to live in more, or less, criminal neighbourhoods according to whether they themselves were criminals

Indeed, it is now clear that children probably now have more nongenetic affect on parents than vice versa. As I argued in the chapter on chromosomes X and Y, it used to be conventional wisdom that distant fathers and over-protective mothers turn sons gay. It is now considered much more likely to be the reverse: perceiving that a son is not fully interested in masculine concerns, the father retreats; the mother compensates by being over-protective.

Es ist zum einen ein schönes Beispiel dafür, dass Biologie gerne übersehen wird und das Erziehungseinflüsse gerne zugunsten von Vererbbarkeit überbewertet werden. Das dürfte einige Beweise betreffen, die in den Sozialwissenschaften gerne präsentiert werden. Studien über adoptierte Kinder und getrennte Zwillinge sind da ein interessanter Studienbereich um weitere Klarheiten zu schaffen.

Zum anderen aber auch in der Sache interessant. Die Erziehung der Eltern hat einen relativ geringen Einfluss, die Gene und auch die Peer-Group dagegen einen höheren.