Francis Galton, 1822-1911, was raised in a high-class intellectual environment near Birmingham, England. He was the youngest of nine children in his wealthy family. His father was a banker, one grandfather was a Fellow of the Royal Society, and his other grandfather Erasmus Darwin was the grandfather of Charles Darwin. Galton showed promising math skills at an early age but originally attended college to study medicine. He became frustrated and discontent with studying medicine, much like his first cousin Charles Darwin, and in 1840 went to Cambridge to read mathematics. After suffering through three years of studying at Cambridge he had a nervous breakdown and returned to the field of medicine.
In 1844 Galtonís father died and left him and his brothers a large inheritance. His brothers were landed gentleman, "devoting their lives to hunting and other forms of refined idleness" (from web site). The large inheritance freed Galton fr om the necessity to work, so in 1845 he traveled throughout the world. He went to Egypt, sailed up the Nile, and crossed the desert to Khartoum. Then made his way to Jerusalem and he settled near Damascus. The letters he wrote to his family suggest he may have contracted a venereal disease while in the Middle East. He returned to London in the fall of 1846 but in 1850 went to explore southern Africa. He helped settle wars between various peoples of southern Africa. Throughout his journey he made man y geographical measurements and upon his return to England in 1850 he received a gold medal by the Royal Geographical Society. Shortly after receiving the award he was elected to the Royal Society. Galton married but the marriage produced no children. He diverted his frustration over his own lack of children into an obsession with Eugenics. He associated intellectual capacity to people with "sturdy frames and large physical strength" (from web site).
Galton was heavily influenced by Darwin and became interested in the heritability of human traits. He believed physical characteristics, such as height, weight, and personality traits and abilities were inherited. The eugenics movement was starte d by Galton himself. He thought the human race could be improved through selective mating. In order to prove this he had to observe a father and son and measure the amount of traits passed on from generation to generation. Galton invented the term &quo t;mental test" (Psychometric Theory) and attempted to measure many human attributes. He recognized the need for standardized testing in which all subjects should be presented the same problems under the same conditions. Most of the tests measured s imple sensory discrimination such as the acuteness of vision, the ability to differentiate colors, and a few other sensory functions.
Galton began his first large-scale testing program at his laboratory in the South Kensington Museum in 1884. Fathers and sons paid Galton to measure their height, weight, breathing power, strength of hearing, sight and color sense. After analyzin g the data, he needed a statistical method to measure the correlation between the characteristics of the fathers and sons. Galton supported a younger colleague, Karl Pearson, in the development of statistical methods for the study of individual differenc es. Pearson developed a method to deal with the measurement of human abilities. I didnít find any results dealing with the correlation between a father and sonís sensory functions and mental capacity. These factors were being dealt with by the newly fo unded field of psychology.
In 1876, Galton conducted a sweet pea experiment using seven groups of seeds. He computed the average diameter of 100 seeds produced by each sweet pea plant. He founded that the smallest pea seeds had larger offspring and the largest seeds had sm aller offspring. In another study, Galton bought family records that contained the heights of 205 sets of parents and their adult children. If the parents were short their children were slightly taller, on the other hand, if the parents were tall then t he children were slightly shorter. These two experiments lead Galton to invent the word regression. Regression is defined as the process of returning to the mean. In both experiments the smallest peas and parents had offspring who were bigger and close r to the mean. The largest peas and parents had offspring who were smaller and once again closer to the mean.
Galton was greatly influenced by his cousin Charles Darwin. Darwin is thought to be responsible for getting Galton interested in studying the heritability of human traits. During Galtonís studies and experiments he invented words such as eugenics and regression. Galton first thought that breeding two smart people would produce an even smarter person. He also thought that breeding two tall people would produce an even taller person. The experiments he performed proved that the idea of eugenics wasnít going to work. This is when the idea of "regression to the mean" (Chance) occurred. These two ideas and/or theories are still being debated but their origins can be directly traced to Galton'í studies.
Nunnally, Jum C. Psychometric Theory. McGraw Ė Hill, Inc. 1978.
Smith, Gary. Chance, "Do Statistics Test Scores Regress Toward the Mean?" Vol. 10, No. 4. Fall, 1997.