to Woodworth, so experiments that claim to demonstrate sharp differences in races ignore overlap within a population. Additionally, Woodworth disagreed with the norm of the time with labeling civilizations as "primitive" or "advanced" because he noted that differences on the evolutionary time scale are likely minute to produce a mental status change . In 1906, the American Psychological Association appointed Woodworth as part of a committee to study psychometrics. With the onset of World War I, APA asked Woodworth to assist them in trying to prevent what was then known as "shell shock". He generated the Woodworth Personal Data Sheet (WPDS), which has been called the first personality test. It was a test of emotional stability to measure a soldier's susceptibility based on existing cases of the disorder. Although the test was designed too late for it to be used operationally, the test was highly influential in the development of later personality inventories with measures of neuroticism. Woodworth published Psychology: A study of mental life, which appeared first in 1921, and Experimental Psychology in 1938, which he worked on for nearly twenty years, and they became the definitive texts for thousands of psychology students. Additionally, Woodworth published Contemporary Schools of Psychology in 1932. He described the history of psychology according to a view that differing schools of psychology are complementary and not incompatible. This tolerant, open-minded view was likely a result of his unique perspective of psychology, being part of the subject for nearly the entire fifty years of its existence. He was renowned for this contribution, later being known as the dean of American Psychology. In 1914, Woodworth was elected president of APA, and in his presidential address, he discussed the question of the existence of imageless thoughts. He spent the summer of 1912 working in Oswald Külpe's lab studying the topic much to Titchener's dismay. According to Titchener, imageless thoughts were not possible. Woodworth disagreed, stating that even if most thoughts have corresponding sensations and/or images, some do not. Woodworth was strongly opposed to "epistemological tables of commandments" such as the strict and narrow approaches of Titchener and Watson, preferring a somewhat eclectic approach. Motivational psychology Woodworth introduced and popularized the expression Stimulus-Organism-Response (S-O-R) to describe his functionalist approach to psychology and to stress its difference from the strictly Stimulus-Response (S-R) approach of the behaviorists in his 1929 second edition of Psychology. He later published the theory in