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Fingerprints as a System of Personal Identification
Galton is perhaps best known for his development of the fingerprint system as a means of personal identification, an achievement rooted in his interest in classifying and comparing human traits. The need for a reliable means of personal identification had become a pressing one in the nineteenth century with the increasing mobility and anonymity of European populations, the institutionalization of law enforcement, and colonialist expansion into Asia and Africa. This need had given rise to Alphonse Bertillon’s elaborate system of criminal identification, which used precise measurements of several body parts coupled with photography; however, Galton was critical of the system’s shortcomings. In the early 1880s Galton learned of the independent fingerprint studies of Henry Faulds and Sir William Herschel (a descendant of the astronomer), both of whom had suggested the use of fingerprints in criminal identification. Faulds had classified fingerprints into the basic categories of whorl, loop and arch (still used today), and had proposed their use in studies of heredity, while Herschel had pointed out the crucial fact that fingerprints do not alter with age. After collecting and studying massive amounts of fingerprint data, Galton read his first paper on the subject in 1890, following it with additional articles and three books. The most important of these was Finger Prints (75), which established the importance of fingerprints in both biological and criminological investigation. “This masterful work of 13 chapters began with the history of fingerprinting, gave detailed descriptions of the various features of fingerprints, their classification, their persistence, evidential value, peculiarities, indexing, inheritance, and their relationship to race and class. . . . The book also set forth detailed instructions for those who wished to apply the technique, as well as recommending equipment and materials such as rollers, dyes, and the best methods for rendering accurate fingerprint impressions photographically” (Gillham, p. 241) and 71-83). But his contributions to science were certainly not limited to fingerprints.
Galton, a first cousin of Charles Darwin, also “made significant contributions to both genetics and psychology. An early proponent of statistical analysis as applied to mental and behavioral phenomena, he developed the correlation method in statistics. He was also an indefatigable explorer and an inquirer into human intelligence, and he made important contributions to the fields of meteorology, anthropometry, and physical anthropology as well.
“Galton, convinced that preeminence in various fields resulted principally from hereditary factors, was inclined to oppose those who stressed environmental determination of either intelligence or character. Interest in the role of heredity led him to introduce the method of twin studies to examine the different contributions of nature and nurture. He also inquired into racial differences and was one of the first to employ questionnaire and survey methods, which he used to investigate mental imagery in different groups. He coined the word eugenics, and his work laid the foundation for the modern eugenics movement” (http://www.cwrl.utexas.edu/~tonya/309m/class/ paper4/bowser/sfg.htm).
Galton was one of the intellectual giants of his time, despite a desultory education that ended at the age of 22, when the death of his father left him a wealthy man. He was mechanically minded and had considerable skill as an inventor—his first publication (1) describes his design for a printing electric telegraph, and he invented a heliostat that was manufactured commercially as “Galton’s Sun Signal”. (2) He also designed several scientific devices to aid him in his anthropometric and statistical researches. (3-5)
Travel and Exploration
Galton first achieved fame as a traveler and an explorer of southwestern Africa, a region then little known to Europeans. Galton’s reports of his first South African journey (1850-52) earned him the gold medal of the Royal Geographical Society in 1853, and later reports led to his election as a Fellow of the Royal Society in 1860. Besides accounts of his travels, Galton also published works containing useful information for travelers. (6-14)
In the 1860s Galton became interested in meteorology, particularly in weather forecasting. It was here that his statistical interests and abilities first made themselves manifest. (15-16)
Heredity and Eugenics
The main focus of Galton’s long career, however, was in the fields of heredity and eugenics, a term Galton introduced in 1883 in his Inquiries into Human Faculty and its Development (60). His interest in these fields was crystallized by the publication in 1859 of Darwin’s Origin of Species, which, as Galton stated in his autobiographical Memories of my Life (84) “made a marked epoch in my own mental development, as it did in human thought generally.” The use of statistical methods was fundamental to Galton’s work in these areas: believing that virtually anything can be quantified, he approached his investigations from that angle, and devised ingenious ways to analyze data in both numeric and graphic form. In so doing, he helped usher in the “statistical revolution” of the 1880s, in which “a series of remarkable men [Galton among them] constructed an empirical and conceptual methodology that provided a surrogate for experimental control and in effect dissipated the fog that had impeded progress [in the social sciences] for a century” (Stigler, Hist. Statistics, p. 265) and (17).
Galton’s first investigations into heredity focused on the heritability of human intelligence, a topic that engrossed him throughout his career. Convinced that human ability depended primarily on inheritance, Galton “hit upon a fairly simple device, the pedigree, one that would remain an analytical mainstay for the rest of his life” (Gillham, p. 155). Galton charted the pedigrees of distinguished men and compared this data to the population of Europe as a whole, noting a much higher frequency of “eminence” in the distinguished families. After publishing some preliminary papers on the subject in Macmillan’s (18), Galton issued his Hereditary Genius (19) in which “he used the same general method of gathering data on a much grander scale and applied the ‘bell curve’ as an evaluative technique for the first time. He had been introduced to ‘the Gaussian Law of Probable Error’ by his old friend William Spottiswoode. . . . Galton now familiarized himself with the work of the Belgian scientist Adolph Quetelet, who first applied the normal distribution to human measurement. . . . Overall Galton’s results in Hereditary Genius seemed to support his thesis that talent and character were largely determined by nature” (Gillham, pp. 157-58, 167). To the Victorian reading public, still trying to absorb the implications of Darwinian theory, this idea was both heretical and shocking: “While most would agree that physical and some mental traits were inherited in animals, they were unprepared to acknowledge this to be true of human beings. The thesis Galton promoted was that human talent and character differed little from the more mundane traits discussed by Darwin to illustrate the selection and breeding of domestic animals and cultivated plants. They should therefore be subject to selection themselves” (Gillham, p. 156).
In English Men of Science (20), published five years later, Galton extended his research on the heritability of talents to include the circumstances under which men of achievement are nurtured. In an attempt to clarify the relative importance of nature and nurture (a phrase Galton is credited with coining; see Gillham, p. 192), he compiled a seven-page questionnaire—a novel data-gathering technique at the time—covering both hereditary and environmental factors. He submitted the questionnaire to 180 select members of the Royal Society; the responses form the basis of further work in this area. (21-26)
As a means of assessing the roles of nature and nurture in the determination of human ability, Galton came up with the idea of studying pairs of identical and non-identical twins, a method still in use today (27).
In 1868 Charles Darwin published Variation of Animals and Plants under Domestication, containing his “pangenesis” theory of heredity: heritable characteristics were passed from parent to offspring via hypothetical particles (“gemmules”) thrown off by an organism’s cells. Galton sought to prove his cousin’s theory by transfusing blood from a mongrel strain of rabbits into a purebred one, hypothesizing that the “gemmules” in the transfused mongrel blood would affect the offspring of the purebred rabbits that received it. This of course proved not to be the case, and Galton reported his negative results in “Experiments in Pangenesis” (28), stating that these “negative[ed], in my opinion, beyond all doubt, the truth of the doctrine of Pangenesis.” Darwin objected to Galton’s interpretation of the pangenesis theory, and Galton responded by writing “On Blood Relationship” and “A Theory of Heredity” (29-30), positing his own theory of inheritance, albeit one heavily influenced by Darwin’s thinking. Galton adopted Darwin’s hypothesis of “patent” and “latent” hereditary elements to explain variation and reversion, but added the important concept of one-way information transfer as a means of ruling out inheritance of acquired characteristics. This paper “represented an important step in the evolution of Galton’s thinking as it meant that mankind could only be improved through selective breeding and not through environmental modifications, since these were not heritable” (Gillham, p. 180).
Galton further discussed heredity in his book Natural Inheritance (51), his greatest scientific work. This book contains “what may be described as the second best theory of heredity. [Galton] came close to deducing several of the fundamental genetic truths arrived at by Mendel. His theory of particulate inheritance with its emphasis on quantitative variation in numbers of different genetic elements actually fitted the metric characters, like stature, he analyzed. . . . On theoretical grounds, Galton had edged close to developing a whole set of important genetic concepts that would emerge early in the twentieth century. But unlike Mendel, he did not know how to test his model and there were no physical structures within the cell on which he could hang his personal and latent [hereditary] elements so far as he knew” (Gillham, pp. 258, 262). The work also contains the beginnings of what Pearson would later name Galton’s Law of Ancestral Heredity (20), as well as a report on the first directional selection experiment (“directional selection” is defined as the natural selection strategy by which one genetic variety in a population is favored while other varieties are reduced or even eliminated from the population because of their lesser fitness).
“Following the publication of Hereditary Genius, Galton’s attack on the human body and mind became two-pronged. The first prong involved the accumulation of quantitative data on easily measurable human physical parameters such as height coupled with the development of methods for their statistical analysis based principally on the properties of the normal distribution. . . . The second prong of Galton’s attack was on human personality and behavior. He wanted to develop methods for characterizing and quantifying human behavior. His desire in this regard led him into explorations as diverse as composite photography, psychology and fingerprinting. The ultimate purpose of these investigations was to establish methods for advancing the quality of the human stock. . .” (Gillham, p. 195).
“To aid his analysis, Galton unveiled a new statistical tool. He wanted a metric that would allow him to arrange any set of measurements on a single statistical scale. He discovered that if he graphed his data in a series of ranks according to the exponential function that describes the normal distribution, he obtained a graceful, sinuous curve that was concave at the bottom and convex at the top. He christened it the ‘ogive’ . . . (Gillham, p. 297). This curve is now known as the inverse normal cumulative distribution function.
To gather data for his investigations, Galton established his own Laboratory of Anthropometry, and he also initiated schemes for gathering anthropometric data, such as height and weight measurements, from a wide range of sources including schools. In 1901 he founded the journal Biometrika in conjunction with Karl Pearson and W. F. R. Weldon; the journal was intended to “serve as a means not only of collecting under one title biological data of kind not systematically collected or published in any other periodical, but also of spreading a knowledge of such statistical theory as may be requisite for their scientific treatment” (quoted in Gillham, p. 307).
“It was [Galton’s] basic aim to distinguish between Englishmen, to investigate the differences among them and the inheritance of these differences. . . . To this end, and in the first of his departures from Quetelet, Galton turned Quetelet’s phenomenon [i.e. , method of fitting normal curves to data] to a novel use. If data from the same species arrayed themselves according to this curve and if the unity of the species could be demonstrated by showing that measurable quantities such as stature or examination scores followed the curve, then, once such a species was identified on the basis of measurable quantities, the process could be inverted with respect to qualities that eluded direct measurement! Qualities such as talent or ‘genius’ that were at most susceptible to a simple ordering could, by Galton’s method, be assigned a value on a ‘statistical scale’ . . . Galton later called this method of analysis ‘statistics by intercomparison’  and it was to become the most used (and abused) method of scaling psychological tests” (Stigler, Hist. Statistics, p. 271).
Galton’s two most significant contributions to statistics—correlation and regression to the mean—grew out of his analyses of anthropometric data. Galton came up with the concept of “regression to the mean” in the mid-1880s, while investigating the heritability of height in humans. In plotting the heights of children against their parents, Galton found that if a child’s “mid-parent” (the average of the male and female parents’ heights, with the mother’s height adjusted upwards) was taller than the mean, the child would tend to be shorter than the mid-parent by a certain ratio, whereas the opposite was true if the mid-parent was shorter than the mean. With the assistance of mathematician J. H. Dickson, Galton came up with a full mathematical formulation of this concept, which is discussed in detail in Natural Inheritance (51), his greatest scientific treatise.
The concept of correlation—defined as the measurement of how closely any two series vary relative to one another—was introduced in Galton’s paper “Co-Relations and their Measurements, Chiefly from Anthropomorphic Data” (48). “After Natural Inheritance went to press, Galton was using his anthropometric data to plot forearm length against height one day when he noticed that the problem was intrinsically the same as that of kinship. He summarized these data in one of the tables in his paper. . . . Galton extended correlation to other physical parameters such as head breadth versus head length, head length versus height, etc. He also determined the first set of correlation coefficients, using the now familiar symbol r. . . . Galton’s pathbreaking memoir of 1888 on correlation, together with his greatest scientific book, Natural Inheritance, not only were the stimuli that activated his first disciples, but would form the cornerstone of a new science, biometrics” (Gillham, p. 258) and (31-59).
Galton introduced the word “eugenics”—“a word whose dark connotations have ever since been associated with his name” (Gillman, p. 207)—in his Inquiries into Human Faculty and its Development (60). He defined the term as “the science of improving stock,” encompassing not only judicious selective breeding but all the various factors that give superior traits an improved chance of prevailing over inferior ones. Galton was of course concerned primarily with improving human stock, particularly in Britain: he sorted the British population into various classes based on distribution of ability and health, analyzed the likelihood of each class’s producing socially desirable offspring, and sought to promote the propagation of the “fittest” classes while discouraging the reproduction of the least fit. Critics objected that the adoption of a eugenics program would subvert an individual’s right to choose a mate at will; Galton answered these objections by investigating the restrictions already inherent in various marriage customs. Galton’s ideas were largely well received in the scientific community, and in 1904 he endowed a chair of eugenics at London University. (61-70)
Statistics and Prayer
Galton also used his statistical methods to investigate the power of prayer, concluding that prayer has no power to affect present or future events (82-83).
Autobiography and Miscellaneous Writings
Galton’s other writings include an autobiography (Memories of my Life), published when he was age 86 (84).
Galton and a few other authors also completed miscellaneous writings on anthropological and other scientific subjects (85-101).
More recent works about Galton include a 349 page text by C. Blacker on Galton’s work in Eugenics (102) and V. Hilts “Guide to Francis Galton’s Men of Science.”
References within this narrative were based primarily on two works: Francis Galton: The Life and Work of a Victorian Genius by D. W. Forrest (1974) and A Life of Sir Francis Galton. From African Exploration to the Birth of Eugenics by Nicholas Wright Gillham (2001).
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