| Abstract: | Behaviour genetics has developed rapidly in the last two decades and has now gone far beyond the stage of merely measuring the extent to which individual differences on a particular behaviour can be attributed to genetic factors. This paper discusses the uses to which genetics can be put in efficient experimental design, in determining the generality of results and, most importantly, in the simultaneous analysis of several behaviours and their relationship to each other and to physical and biochemical parameters. Because the principles of genetics apply to all organisms, the first animal discussed is Drosophila, the vinegar fly, which is a vital tool in genetics but which has met with scant attention among psychologists. Drosophila has some unique advantages such as the sex mosaic technique for studying sexual behaviour, but most of the discussion concerns learning and the extent to which parallels can be found between Drosophila and the vertebrates, both in terms of process and of genetic control. It is demonstrated how strain differences and the response to artificial selection can distinguish between learning and other components of behaviour. Drosophila are also used to explain how the type of genetic control can suggest the way in which natural selection acts upon the particular behaviour and further examples from rodents are discussed to show that this is a general result across species. There are many inbred strains and selection lines of mice and rats and examples from a wide range of behaviours illustrate the advantages of using such stocks. The concept of the ‘behavioural phenotype’ is explained, where genetic differences on a wide range of behaviours are considered, rather than just focusing on one behaviour or one response to a particular drug or environmental treatment. Many different aspects of open-field behaviour, learning and mother-infant interaction are used as examples of this concept. The extent of genotype-environmental interaction is considered, since the possibility that each genotype will have a unique response to a particular treatment has considerable implications for the generality and replicability of results. The paper concludes with a brief discussion of human behaviour genetics, since here again the concern is not just with the trivial question of measuring ‘heritability’, but rather with how such information can be used to understand behaviour. The final suggestion is that psychology may gain by having more contact not only with geneticists, but also with the ecologists concerned with the significance of behavioural differences in the wild. |
