Galton was one of the first experimental psychologists, and the founder of the field of enquiry now called Differential Psychology, which concerns itself with psychological differences between people, rather than on common traits. He started virtually from scratch, and had to invent the major tools he required, right down to the statistical methods - correlation and regression - which he later developed. These are now the nuts-and-bolts of the empirical human sciences, but were unknown in his time. One of the principal obstacles he had to overcome was the treatment of differences on measures as measurement error, rather than as natural variability.
His influential study Hereditary Genius (1869) was the first systematic attempt to investigate the effect of heredity on intellectual abilities, and was notable for its use of the bell-shaped Normal Distribution, then called the "Law of Errors", to describe differences in intellectual ability, and its use of pedigree analysis to determine hereditary effects.
Later Galton went on to suggest the use of twin studies to disentangle nature from nurture, by comparing identical twins to fraternal twins. The research program that Galton initiated in this regard has developed into the important field of behaviour genetics.
Galton later broadened his study of human traits into general anthropometry, or "measurement of man", trying to find as many measurable traits as possible, so that their distribution and heritability could be determined.
His psychological studies also embraced mental differences in visualization, and he was the first to identify and study "number forms", now called "synaesthesia". He also invented the word-association test, and investigated the operations of the sub-conscious mind. His work in this area was collected into a wide-ranging volume called Inquiries into Human Faculty, which must be read today with Galton's broader research program in mind: to identify and measure variable human traits.
Inheritance of ability
|Facsimile||Paper||1865||'Hereditary talent and character.'||Macmillan's Magazine 12 : 157-66, 318-27|
|Facsimile||Letter||1868||'Hereditary genius.' [Letter]||Notes and Queries on China and Japan 2 (1, January)|
|Facsimile||Paper||1869||Hereditary Genius: the Judges of England between 1660 and 1865.||Macmillan's Magazine : 424-431|
|Facsimile||Paper||1871||Gregariousness in cattle and in men.||Macmillan's Magazine 23 : 353-57|
|Paper||1877||'La psychophysique'||La Revue Scientifique 13 : 494-8|
|Facsimile||Paper||1880||'Mental imagery'||Fortnightly Review 28 : 312-24|
|Facsimile||Paper||1880||'Visualised numerals.'||Nature 21 : 252-6, 494-5|
|Facsimile||Letter||1880||'Visualised numerals.' [Letter]||Nature 21 : 323|
|Facsimile||Paper||1881||'The visions of sane persons.'||Fortnightly Review 29 : 729-40|
|Facsimile||Paper||1881||'Visualised numerals.'||Journal of the Anthropological Institute 10 : 85-102|
|Facsimile||Paper||1881||'The visions of sane persons.' [with slight variations]||Proceedings of the Royal Institution 9 (May 13) : 644-55|
|Facsimile||Paper||1884||'Free-will-observations and inferences.'||Mind 9 : 406-13|
|Facsimile||Paper||1886||Supplementary notes on "Prehension in idiots".||Mind 12 : 79-82|
|Facsimile||Letter||1887||'Thoughts without words.' [Letters]||Nature 36 : 28-9, 100-1|
|Facsimile||Letter||1887||Thoughts without Words [Letters]||Open Court 1 : 441-4, 472-4, 498-50|
|Facsimile||Paper||1891||[Discussion on 'An apparent paradox in mental evolution', Lady Welby]||Journal of the Anthropological Institute 20 : 304-23|
|Facsimile||Review||1894||'Psychology of mental arithmeticians and blindfold chess-players.' [Review of Psychologic des Grands Calculateurs et Joueurs d'Echecs, Alfred Binet]||Nature 51 : 73-4|
|Facsimile||Paper||1894||'Arithmetic by smell.'||Psychological Review 1 : 61-2|
|Facsimile||Review||1895||'Personality,' [Review of The Diseases of Personality, Th. Ribot]||Nature 52 : 517-8|
|Facsimile||Paper||1896||'A curious idiosyncrasy.'||Nature 54 : 76|
|Facsimile||Review||1898||'Evolution of the moral instinct.' [Review of The Origin and Growth of the Moral Instinct, Alexander Sutherland] (Signed F.G.).||Nature 58 : 241-2|
|Facsimile||Paper||1879||'Psychometric experiments.'||Brain 2 : 149-62|
|Facsimile||Paper||1879||'Psychometric facts.'||Nineteenth Century (March) : 425-33|
|Facsimile||Paper||1880||'Statistics of mental imagery.'||Mind 5 : 301-18|
|Facsimile||Paper||1884||'Measurement of character.'||Fortnightly Review 36 : 179-85|
|Facsimile||Report||1884||The Measurement of Human Faculty' (Rede Lecture)||Nature 31|
|Facsimile||Paper||1889||'An instrument for measuring reaction time.'||Report of the British Association for the Advancement of Science 59 : 784-5|
|Facsimile||Paper||1890||'Exhibition of instruments (1) for testing the perception of differences of tint, and (2) for determining reaction-time.'||Journal of the Anthropological Institute 19 : 27-9|
|Facsimile||Paper||1890||[Remarks following 'Mental tests and measurements', J. McK. Cattell]||Mind 15 : 380-1|
|Facsimile||Paper||1893||'Measure of the imagination.'||Nature 47 : 319-21|
|Facsimile||Paper||1893||'The just-perceptible difference.'||Proceedings of the Royal Institution 14 : 13-26|