Galton’s conclusion raised a fascinating possibility: selective breeding. If intelligence is inherited, could not the general intelligence of a people be improved by encouraging the mating of bright people and discouraging the mating of people who were less bright? Galton’s answer was yes. He called the improvement of living organisms through selective breeding eugenics and advocated its practice:
I propose to show in this book that a man’s natural abilities are derived by inheritance, under exactly the same limitations as are the form and physical features of the whole organic world. Consequently, as it is easy, notwithstanding those limitations, to obtain by careful selection a permanent breed of dogs or horses gifted with peculiar powers of running, or of doing anything else, so it would be quite practicable to produce a highly-gifted race of men by judicious marriages during several consecutive generations. I shall show that social agencies of an ordinary character, whose influences are little suspected, are at this moment working towards the degradation of human nature, and that others are working towards its improvement. I conclude that each generation has suggested that climate, religious tolerance, democratic government, and a thriving economy were at least as important as inherited capacity in producing scientists.
Such criticism prompted Galton’s next book, English Men of Science: Their Nature and Nurture (1874). To gather information for this book, Galton sent a questionnaire to 200 of his fellow scientists at the Royal Society. This was the first use of the questionnaire in psychology. The participants were asked many factual questions, ranging from their political and religious backgrounds to their hat sizes. In addition, they were asked to explain why they had become interested in science in general as well as in their particular branches of science. Finally, the scientists were asked whether they thought that their interest in science was innate.