Psychological instruments at the turn of the century.

Psychology at the turn of the last century was primarily a natural science in its approach. Its goals paralleled those of experimental physiology and physics that had been so successful earlier in the 19th century. The use of scientific instruments to produce stimuli and record responses in psychological experiments became the hallmark for this new psychology of the laboratory. The origins, role, and significance of some of these instruments are discussed as well as the role of instrument makers and their patrons.