Francis Galton

Sir Francis Galton (; 16 February 1822 – 17 January 1911) was an English polymath and the originator of eugenics during the Victorian era; his ideas later became the basis of behavioural genetics.

Galton produced over 340 papers and books. He also developed the statistical concept of correlation and widely promoted regression toward the mean. He was the first to apply statistical methods to the study of human differences and inheritance of intelligence, and introduced the use of questionnaires and surveys for collecting data on human communities, which he needed for genealogical and biographical works and for his anthropometric studies. He popularised the phrase "nature versus nurture". His book Hereditary Genius (1869) was the first social scientific attempt to study genius and greatness.

As an investigator of the human mind, he founded psychometrics and differential psychology, as well as the lexical hypothesis of personality. He devised a method for classifying fingerprints that proved useful in forensic science. He also conducted research on the power of prayer, concluding it had none due to its null effects on the longevity of those prayed for. His quest for the scientific principles of diverse phenomena extended even to the optimal method for making tea. As the initiator of scientific meteorology, he devised the first weather map, proposed a theory of anticyclones, and was the first to establish a complete record of short-term climatic phenomena on a European scale. He was Charles Darwin's half-cousin.

In recent years, he has received significant criticism for being a proponent of social Darwinism, eugenics, and biological racism; indeed he was a pioneer of eugenics, coining the term itself in 1883.

Galton is credited with popularizing the phrase "nature versus nurture" to frame the academic discussion regarding the relative influence of heredity and environment on human ability and social advancement.

Early life

Galton was born at "The Larches", a large house in the Sparkbrook area of Birmingham, England, built on the site of "Fair Hill", the former home of Joseph Priestley, which the botanist William Withering had renamed. He was Charles Darwin's half-cousin, sharing the common grandparent Erasmus Darwin. His father was Samuel Tertius Galton, son of Samuel Galton Jr. He was also a cousin of Douglas Strutt Galton. The Galtons were Quaker gun-manufacturers and bankers, while the Darwins were involved in medicine and science.

Both the Galton and Darwin families included Fellows of the Royal Society and members who loved to invent in their spare time. Both Erasmus Darwin and Samuel Galton were founding members of the Lunar Society of Birmingham, which included Matthew Boulton, James Watt, Josiah Wedgwood, Joseph Priestley and Richard Lovell Edgeworth. Both families were known for their literary talent. Erasmus Darwin composed lengthy technical treatises in verse. Galton's aunt Mary Anne Galton wrote on aesthetics and religion, and her autobiography detailed the environment of her childhood populated by Lunar Society members.

thumb|upright|Portrait of Galton by [[Octavius Oakley, 1840]]

Galton was 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. 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, Cambridge, from 1840 to early 1844. and he terminated his medical studies entirely, turning to foreign travel, sport and technical invention.

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

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 book on his experience, Narrative of an Explorer in Tropical South Africa. He was awarded the Royal Geographical Society's Founder's 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.

Career

Early scientific career

Galton was a polymath who made important contributions in many fields, including meteorology (the anticyclone and the first popular weather maps), statistics (regression and correlation), psychology (synaesthesia), biology (the nature and mechanism of heredity), and criminology (fingerprints). Much of this was influenced by his penchant for counting and measuring. Galton prepared the first weather map published in The Times (1 April 1875, showing the weather from the previous day, 31 March), now a standard feature in newspapers worldwide. Galton established a research program which embraced multiple aspects of human variation, from mental characteristics to height; from facial images to fingerprint patterns. This required inventing novel measures of traits, devising large-scale collection of data using those measures, and in the end, the discovery of new statistical techniques for describing and understanding the data.

Galton was interested at first in the question of whether human ability was hereditary, and proposed to count the number of the relatives of various degrees of eminent men. The address was published in Nature, and Galton further developed the theory in "Regression toward mediocrity in hereditary stature" and "Hereditary Stature". An elaboration of this theory was published in 1889 in Natural Inheritance. There were three key developments that helped Galton develop this theory: the development of the law of error in 1874–1875, the formulation of an empirical law of reversion in 1877, and the development of a mathematical framework encompassing regression using human population data during 1885.

Galton's development of the law of regression to the mean, or reversion, was due to insights from the Galton board ('bean machine') and his studies of sweet peas. While Galton had previously invented the quincunx prior to February 1874, the 1877 version of the quincunx had a new feature that helped Galton demonstrate that a normal mixture of normal distributions is also normal. Galton demonstrated this using a new version of quincunx, adding chutes to the apparatus to represent reversion. When the pellets passed through the curved chutes (representing reversion) and then the pins (representing family variability), the result was a stable population. On Friday 19 February 1877, Galton gave a lecture entitled Typical Laws of Heredity at the Royal Institution in London. In this lecture, he posited that there must be a counteracting force to maintain population stability. However, this model required a much larger degree of intergenerational natural selection than was plausible.

In 1875, Galton began 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 centred on 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, he demonstrated that there was variability among each of the families, yet the families combined to produce a stable, normally distributed population. When he 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 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.

The same year, Galton suggested in a letter to the journal Nature a better method of cutting a round cake by avoiding making radial incisions.

Experimental derivation of the normal distribution

thumb|Galton's 1889 illustration of the quincunx or [[Galton board]]

Studying variation, Galton invented the Galton board, a pachinko-like device also known as the bean machine, as a tool for demonstrating the law of error and the normal distribution.

Bivariate normal distribution

He also discovered the properties of the bivariate normal distribution and its relationship to correlation and regression analysis.

Correlation and regression

thumb|Galton's correlation diagram 1886

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.

Galton invented the use of the regression line and for the choice of r (for reversion or regression) to represent the correlation coefficient.

In the 1870s and 1880s he was a pioneer in the use of normal theory to fit histograms and ogives 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.

Regression toward the mean

Galton was the first to describe and explain the common phenomenon of regression toward the mean, which he first observed in his experiments on the size of the seeds of successive generations of sweet peas.

The conditions under which regression toward the mean occurs depend on the way the term is mathematically defined. Galton first observed the phenomenon in the context of simple linear regression of data points. Galton developed the following model: pellets fall through a quincunx or "bean machine" forming a normal distribution centred directly under their entrance point. These pellets could then be released down into a second gallery (corresponding to a second measurement occasion). Galton then asked the reverse question "from where did these pellets come?"

Theories of perception

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.

He made a beauty map of Britain, based on a secret grading of the local women on a scale from attractive to repulsive. The lowest point was in Aberdeen.

Differential psychology

Galton's study of human abilities ultimately led to the foundation of differential psychology and the formulation of the first mental tests. He was interested in measuring humans in every way possible. This included measuring their ability to make sensory discrimination which he assumed was linked to intellectual prowess. Galton suggested that individual differences in general ability are reflected in performance on relatively simple sensory capacities and in speed of reaction to a stimulus, variables that could be objectively measured by tests of sensory discrimination and reaction

time. He also measured how quickly people reacted which he later linked to internal wiring which ultimately limited intelligence ability. Throughout his research Galton assumed that people who reacted faster were more intelligent than others.

Composite photography

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).

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.

Galton hoped his technique would aid medical diagnosis, and even criminology through the identification of typical criminal faces. However, his technique did not prove useful and fell into disuse, although after much work on it including by photographers Lewis Hine, John L. Lovell and Arthur Batut.

Fingerprints

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. Galton was introduced to the field by his half-cousin Charles Darwin, who was a friend of Faulds, and he went on to create the first scientific footing for the study (which assisted its acceptance by the courts) although Galton did not ever give credit that the original idea was not his. According to the Encyclopedia of Genocide, Galton bordered on the justification of genocide when he stated: "There exists a sentiment, for the most part quite unreasonable, against the gradual extinction of an inferior race."

In an effort to reach a wider audience, Galton worked on a novel entitled Kantsaywhere from May until December 1910. The novel described a utopia organised by a eugenic religion, designed to breed fitter and smarter humans. His unpublished notebooks show that this was an expansion of material he had been composing since at least 1901. He offered it to Methuen for publication, but they showed little enthusiasm. Galton wrote to his niece that it should be either "smothered or superseded". His niece appears to have burnt most of the novel, offended by the love scenes, but large fragments survived, and it was published online by University College, London.

Personal life

In January 1853, Galton met Louisa Jane Butler (1822–1897); they married on 1 August 1853. Their marriage of 43 years ended with the death of Galton's wife. They had no children. He also corresponded with Beatrix Lucia Catherine Tollemache.

Galton is buried in the family tomb in the churchyard of St Michael and All Angels, in the village of Claverdon, Warwickshire.

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.

The flowering plant genus Galtonia was named after Galton.

University College London has in the twenty-first century been involved in a historical inquiry into its role as the institutional birthplace of eugenics. Galton established a laboratory at UCL in 1904. Some students and staff have called on the university to rename its Galton lecture theatre, with journalist Angela Saini stating, "Galton's seductive promise was of a bold new world filled only with beautiful, intelligent, productive people. The scientists in its thrall claimed this could be achieved by controlling reproduction, policing borders to prevent certain types of immigrants, and locking away "undesirables", including disabled people."

In June 2020, University College London (UCL) announced the renaming of a lecture theatre named after Galton because of his connection with eugenics.

Published works

Collections

After Galton's death in 1911, his archive donated to University College London by his executors. The Galton Papers include material about Galton's personal life and family, correspondence, and papers relating to his scientific work.

University College London also holds the papers of Galton's protégé Karl Pearson, the records of the Galton Laboratory, and successors to the Galton Professor role including J.B.S. Haldane and L.S. Penrose.

The Royal Geographical Society holds material relating to Galton including photographs, correspondence and a telescope he used in expeditions.