Francis Galton (1822 - 1911)

Francis Galton (1822-1911) was an inveterate measurer who embarked on a natural history of human perception and performance. He measured intelligence and mental imagery, and introduced the methods of word association and of the twin studies. In addition, he introduced fingerprinting as a method of identifying individuals; invented the weather map; and assessed both the beauty of women and the boredom of lectures. His impact was most keenly felt in the area of individual differences. Not only did he appreciate that differences could be measured but he also devised a means for comparing them. This was perhaps his most lasting achievement. Rather than comparing the measures themselves they could be related in terms of their variability. This insight arose from his analysis of hereditary genius. Galton was a cousin of Charles Darwin, and was greatly influenced by the theory of evolution. He developed an early interest in personal differences of mental function, linking them both with sensory discrimination and with reaction time. He combined the Darwinian concepts of variability and adaptation with his mathematical learnings to measure individual differences in behavior, culminating in his Anthropometric Laboratory (1884) at which thousands paid to have their physical and mental characteristics measured. Galton proposed that mental abilities were normally distributed in the population after the manner of Quetelet's bell-shaped curves for height and weight, and that they were inherited. He sought support for the importance of nature over nurture (terms he introduced in this context) by asking eminent scientists to complete questionnaries. It was in considering these data in 1888 that Galton "first clearly grasped the important generalization that the laws of heredity were solely concerned with deviations expressed in statistical units." This was supported by the analysis of data collected from earlier laborious measurements of the dimensions of sweet pea seeds over two generations; he found that the offspring mean reverted to the mean of the population and he tried to devise a measure of this reversion (or regression). - page 67