ABSTRACT
In 1850, Hermann von Helmholtz (1821–1894) published his measurements concerning the speed of neural conduction. Franciscus Donders (1818–1889) recognized that if neural conduction took a measurable amount of time, then thinking also must take time, and he devised a research program in which tasks were divided into their constituent subtasks and the time required to complete each subtask could then be measured (Donders, 1969). Thus, mental chronometry was born, and now there is not a field in psychology or human performance that does not use response time (RT) measures to evaluate behavior, models of cognition, engineering designs, and even mental and physical health.
