Francis Galton

Galton attended King Edward's School, Birmingham, but chafed at the narrow classical curriculum and left at 16. His parents pressed him to enter the medical profession, and he studied for two years at Birmingham General Hospital and King's College London Medical School. He followed this up with mathematical studies at Trinity College, University of Cambridge, from 1840 to early 1844.

According to the records of the United Grand Lodge of England, it was in February 1844 that Galton became a freemason at the so-called Scientific lodge, held at the Red Lion Inn in Cambridge, progressing through the three masonic degrees as follows: Apprentice, 5 February 1844; Fellow Craft, 11 March 1844; Master Mason, 13 May 1844. A curious note in the record states: "Francis Galton Trinity College student, gained his certificate 13 March 1845". One of Galton's masonic certificates from Scientific lodge can be found among his papers at University College, London.

In his early years Galton was an enthusiastic traveller, and made a notable solo trip through Eastern Europe to Constantinople, before going up to Cambridge. In 1845 and 1846 he went to Egypt and travelled down the Nile to Khartoum in the Sudan, and from there to Beirut, Damascus and down the Jordan.

In 1846, the French Physicist Auguste Bravais (1811–1863) first developed what would become the correlation coefficient. After examining forearm and height measurements, Galton independently rediscovered the concept of correlation in 1888 and demonstrated its application in the study of heredity, anthropology, and psychology. Galton's later statistical study of the probability of extinction of Surnames led to the concept of Galton–Watson stochastic processes. This is now a core of modern statistics and regression.

A severe nervous breakdown altered Galton's original intention to try for honours. He elected instead to take a "poll" (pass) B.A. degree, like his half-cousin Charles Darwin. (Following the Cambridge custom, he was awarded an M.A. without further study, in 1847.) He then briefly resumed his medical studies. The death of his father in 1844 had left him financially independent but emotionally destitute, and he terminated his medical studies entirely, turning to foreign travel, sport and technical invention.

In 1850 he joined the Royal Geographical Society, and over the next two years mounted a long and difficult expedition into then little-known South West Africa (now Namibia). He wrote a successful book on his experience, "Narrative of an Explorer in Tropical South Africa". He was awarded the Royal Geographical Society's Founder's Gold Medal in 1853 and the Silver Medal of the French Geographical Society for his pioneering cartographic survey of the region. This established his reputation as a geographer and Explorer. He proceeded to write the best-selling The Art of Travel, a handbook of practical advice for the Victorian on the move, which went through many editions and is still in print.

In January 1853, Galton met Louisa Jane Butler (1822–1897) at his neighbour's home and they were married on 1 August 1853. The union of 43 years proved childless.

He became very active in the British Association for the Advancement of Science, presenting many papers on a wide variety of topics at its meetings from 1858 to 1899. He was the general secretary from 1863 to 1867, President of the Geographical section in 1867 and 1872, and President of the Anthropological Section in 1877 and 1885. He was active on the council of the Royal Geographical Society for over forty years, in various committees of the Royal Society, and on the Meteorological Council.

The publication by his cousin Charles Darwin of The Origin of Species in 1859 was an event that changed Galton's life (Forrest 1974, p. 84). He came to be gripped by the work, especially the first chapter on "Variation under Domestication", concerning animal breeding.

The method of identifying Criminals by their fingerprints had been introduced in the 1860s by Sir William James Herschel in India, and their potential use in forensic work was first proposed by Dr Henry Faulds in 1880, but Galton was the first to place the study on a scientific footing, which assisted its acceptance by the courts. Galton pointed out that there were specific types of fingerprint patterns. He described and Classified them into eight broad categories: 1: plain arch, 2: tented arch, 3: simple loop, 4: central pocket loop, 5: double loop, 6: lateral pocket loop, 7: plain whorl, and 8: accidental.

Galton conducted wide-ranging inquiries into heredity which led him to challenge Charles Darwin's hypothesis of pangenesis. Darwin had proposed as part of this model that certain particles, which he called "gemmules" moved throughout the body and were also responsible for the inheritance of acquired characteristics. Galton, in consultation with Darwin, set out to see if they were transported in the blood. In a long series of experiments in 1869 to 1871, he transfused the blood between dissimilar breeds of rabbits, and examined the features of their offspring. He found no evidence of characters transmitted in the transfused blood.

In the 1870s and 1880s he was a pioneer in the use of normal theory to fit histograms to actual tabulated data, much of which he collected himself: for instance large samples of sibling and parental height. Consideration of the results from these empirical studies led to his further insights into evolution, natural selection, and regression to the mean.

The method used in Hereditary Genius has been described as the first Example of historiometry. To bolster these results, and to attempt to make a distinction between 'nature' and 'nurture' (he was the first to apply this phrase to the topic), he devised a questionnaire that he sent out to 190 Fellows of the Royal Society. He tabulated characteristics of their families, such as birth order and the occupation and race of their parents. He attempted to discover whether their interest in science was 'innate' or due to the encouragements of others. The studies were published as a book, English men of science: their nature and nurture, in 1874. In the end, it promoted the nature versus nurture question, though it did not settle it, and provided some fascinating data on the sociology of Scientists of the time.

Galton recognised the limitations of his methods in these two works, and believed the question could be better studied by comparisons of twins. His method envisaged testing to see if twins who were similar at birth diverged in dissimilar environments, and whether twins dissimilar at birth converged when reared in similar environments. He again used the method of questionnaires to gather various sorts of data, which were tabulated and described in a paper The history of twins in 1875. In so doing he anticipated the modern field of behaviour genetics, which relies heavily on twin studies. He concluded that the evidence favoured nature rather than nurture. He also proposed adoption studies, including trans-racial adoption studies, to separate the effects of heredity and environment.

In 1875, Galton started growing sweet peas and addressed the Royal Institution on his findings on 9 February 1877. He found that each group of progeny seeds followed a normal curve, and the curves were equally disperse. Each group was not centered about the parent's weight, but rather at a weight closer to the population average. Galton called this reversion, as every progeny group was distributed at a value that was closer to the population average than the parent. The deviation from the population average was in the same direction, but the magnitude of the deviation was only one-third as large. In doing so, Galton demonstrated that there was variability among each of the families, yet the families combined to produce a stable, normally distributed population. When Galton addressed the British association for the advancement of science in 1885, he said of his investigation of sweet peas, "I was then blind to what I now perceive to be the simple explanation of the phenomenon."

Galton went beyond measurement and summary to attempt to explain the phenomena he observed. Among such developments, he proposed an early theory of ranges of sound and hearing, and collected large quantities of anthropometric data from the public through his popular and long-running Anthropometric Laboratory, which he established in 1884, and where he studied over 9,000 people. It was not until 1985 that these data were analysed in their entirety.

This work began in the 1880s while the Jewish scholar Joseph Jacobs studied anthropology and statistics with Francis Galton. Jacobs asked Galton to create a composite photograph of a Jewish type. One of Jacobs' first publications that used Galton's composite imagery was "The Jewish Type, and Galton's Composite Photographs," Photographic News, 29, (24 April 1885): 268–269.

In a Royal Institution paper in 1888 and three books (Finger Prints, 1892; Decipherment of Blurred Finger Prints, 1893; and Fingerprint Directories, 1895), Galton estimated the probability of two persons having the same fingerprint and studied the heritability and racial differences in fingerprints. He wrote about the technique (inadvertently sparking a controversy between Herschel and Faulds that was to last until 1917), identifying Common pattern in fingerprints and devising a classification system that survives to this day.

The model for population stability resulted in Galton's formulation of the Law of Ancestral Heredity. This law, which was published in Natural Inheritance, states that the two parents of an offspring jointly contribute one half of an offspring's heritage, while the other, more-removed ancestors constitute a smaller proportion of the offspring's heritage. Galton viewed reversion as a spring, that when stretched, would return the distribution of traits back to the normal distribution. He concluded that evolution would have to occur via discontinuous steps, as reversion would neutralize any incremental steps. When Mendel's principles were rediscovered in 1900, this resulted in a fierce battle between the followers of Galton's Law of Ancestral Heredity, the biometricians, and those who advocated for Mendel's principles.

This approach was later taken up enthusiastically by Karl Pearson and W.F.R. Weldon; together, they founded the highly influential journal Biometrika in 1901. (R.A. Fisher would later show how the biometrical approach could be reconciled with the Mendelian approach.) The statistical techniques that Galton invented (correlation, regression—see below) and phenomena he established (regression to the mean) formed the basis of the biometric approach and are now essential tools in all the social sciences.

Galton was a keen observer. In 1906, visiting a livestock fair, he stumbled upon an intriguing contest. An ox was on display, and the villagers were invited to guess the animal's weight after it was slaughtered and dressed. Nearly 800 participated, and Galton was able to study their individual entries after the event. Galton stated that "the middlemost estimate expresses the vox populi, every other estimate being condemned as too low or too high by a majority of the voters", and reported this value (the median, in terminology he himself had introduced, but chose not to use on this occasion) as 1,207 pounds. To his surprise, this was within 0.8% of the weight measured by the judges. Soon afterwards, in response to an enquiry, he reported the mean of the guesses as 1,197 pounds, but did not comment on its improved accuracy. Recent archival research has found some slips in transmitting Galton's calculations to the original article in Nature: the median was actually 1,208 pounds, and the dressed weight of the ox 1,197 pounds, so the mean estimate had zero error. James Surowiecki uses this weight-judging competition as his opening example: had he known the true result, his conclusion on the wisdom of the crowd would no doubt have been more strongly expressed.

Galton was knighted in 1909. His statistical heir Karl Pearson, first holder of the Galton Chair of Eugenics at University College London (now Galton Chair of Genetics), wrote a three-volume biography of Galton, in four parts, after his death (Pearson & 1914, 1924, 1930). In the early days of IQ testing, Lewis Terman estimated that Galton's childhood IQ was about 200, based on the fact that he consistently performed mentally at roughly twice his chronological age (Forrest 1974). (This follows the original definition of IQ as mental age divided by chronological age, rather than the modern definition based on the standard distribution and standard deviation.)

Over the course of his career Galton received many major awards, including the Copley Medal of the Royal Society (1910). He received in 1853 the Founder's Medal, the highest award of the Royal Geographical Society, for his explorations and map-making of southwest Africa. He was elected a member of the prestigious Athenaeum Club in 1855 and made a Fellow of the Royal Society in 1860. His autobiography also lists the following:

Galton also devised a technique called "composite portraiture" (produced by superimposing multiple photographic portraits of individuals' faces registered on their eyes) to create an average face (see averageness). In the 1990s, a hundred years after his discovery, much psychological research has examined the attractiveness of these faces, an aspect that Galton had remarked on in his original lecture. Others, including Sigmund Freud in his work on dreams, picked up Galton's suggestion that these composites might represent a useful metaphor for an Ideal type or a concept of a "natural kind" (see Eleanor Rosch)—such as Jewish men, Criminals, patients with tuberculosis, etc.—onto the same photographic plate, thereby yielding a blended whole, or "composite", that he hoped could generalise the facial appearance of his subject into an "average" or "central type". (See also entry Modern physiognomy under Physiognomy).

Galton was by many accounts a child prodigy – he was reading by the age of two; at age five he knew some Greek, Latin and long division, and by the age of six he had moved on to adult books, including Shakespeare for pleasure, and poetry, which he quoted at length. Later in life, Galton would propose a connection between genius and insanity based on his own experience. He stated:

Galton states that the measurements of human characteristics are useful for two reasons. First, he states that measuring physical characteristics is useful in order to ensure, on a more domestic level, that children are developing properly. A useful Example he gives for the practicality of these domestic measurements is regularly checking a child’s eyesight, in order to correct any deficiencies early on. The second use for the data from his anthropometric laboratory is for statistical studies. He comments on the usefulness of the collected data to compare attributes across occupations, residences, races, etc. The exhibit at the health exhibition allowed Galton to collect a large amount of raw data from which to conduct further comparative studies. He had 9,337 respondents, each measured in 17 categories, creating a rather comprehensive statistical database.