Douglas Alexander Spalding (1841–1877) was an English biologist. He was born in Islington in London in 1841, and began life as a manual labourer. Subsequently he lived in Scotland, near Aberdeen; the philosopher Alexander Bain persuaded the University of Aberdeen to allow him to attend courses without charge. He studied philosophy and literature, but after a year left for London. He trained as a lawyer, but also contracted tuberculosis. He travelled in Europe in hopes of finding a cure, and in Avignon met John Stuart Mill and through him Viscount Amberley (son of the former British Prime Minister Lord John Russell, by then 1st Earl Russell). He became tutor to Viscount Amberley's children, including perhaps the very young Bertrand Russell, and also carried on an intermittent affair with Viscountess Amberley. After the viscount's death in 1876, Spalding returned to the continent and remained there until his death the following year.
Spalding carried out some remarkable experiments on animal behaviour, and discovered the phenomenon now known as imprinting, later rediscovered by Oskar Heinroth, then studied at length and popularised by Konrad Lorenz. He was greatly ahead of his time in his recognition of the importance of the interaction between learning and instinct in determining behaviour, and in his use of the experimental method in studying behaviour. Although his work is little known nowadays, its importance is recognised by historians of psychology; the biologist J. B. S. Haldane reprinted Spalding's essay "On Instinct" in 1954 to clarify the history of the subject.[1]