the human species through selective breeding of gifted individuals.Between 1884 and 1890 Galton operated a laboratory at the South Kensington Museum in London (now the Victoria and Albert Museum) where, for a small fee, people could have themselves measured on a number of physical and psychological attributes. He tried to relate intellectual ability to skills such as reaction time, sensitivity to physical stimuli, and body proportions. For example, he measured the highest and lowest pitch a person could hear and how well a person could detect minute differences between weights, colors, smells, and other physical stimuli. Despite the crude nature of his measurements, Galton was a pioneer in the study of individual differences. His work helped develop statistical concepts and techniques still in use today. He also was the first to advance the idea that intelligence can be quantitatively measured.In the 1890s American psychologist, James Cattell who worked with Galton in England, developed a battery of 50 tests that attempted to measure basic mental ability. Like Galton, Cattell focused on measurements of sensory discrimination and reaction times. Cattell's work—and by association, Galton's—was unsupported in 1901, when a study showed that the measurements had no correlation with academic achievement in college. Later researchers, however, pointed out that Cattell's test subjects were limited to Columbia University students, whose high academic performance was not representative of the general population. Better-designed tests given to broader samples have shown that reaction time and processing speed on perceptual tasks do correlate with academic achievement.Mental age IQ and Deviation IQIn an effort to convert the Mental age Scores into a uniform index of the individual’s status, the Ratio IQ was introduced in early intelligence tests.This IQ was basically the ratio of the mental age to the chronological age multiplied...
