New Improvements in the Old
The inheritance of behavior has been a subject of debate for many generations, but it is only very recently that the debate became grounded in observation and experiment. Prior to the use of the new tools of molecular biology, the debate about nature and nurture created much more heat than light. But the recent advances in molecular genetics, described briefly in the previous chapter, have now made it possible to address objectively questions that interest virtually everyone. In fact, some of the more pressing questions have even been given a satisfactory answer. This is not to say that any single question has been definitively answered; quite likely it will take another generation to really settle some issues. But scientists have made some real progress.
At the same time that molecular biology was blossoming as an approach to behavioral genetics, there were also some striking advances in the other tools used to study behavioral genetics. Some of these tools have been used for many years, but there have been cumulative improvements that now make the old tools new again. In fact, several of the old tools have improved so much that it is appropriate to think of them as essentially new tools.
The greatest weakness of psychology, and consequently also of behavioral genetics, has been the psychological testing tools