William James (1842-1910), US psychologist and philosopher. James stressed the need to study the mind as a useful and functioning part of an organism. After the publication of his ideas in Principles of Psychology (1890), psychology was viewed as an independent science rather than being just a branch of philosophy as it had been previously. James pioneered the use of experimental psychology. This technique allowed the development of intelligence tests for humans and tests to see how quickly animals learnt to solve problems. James also studied moral and religious beliefs and behaviour. Photographed by Alice Boughton (1866-1943).