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Introduction
Since the 1980s, psychologist Richard Lynn has argued that people of different races differ in their average intelligence, that this racial pattern of intelligence holds internationally, and that it is partly explained by genetic factors (Lynn, 1987, 1991, 2006a, 2006b, 2008). As well as anchoring his claims with data from IQ testing, Lynn has supplemented his case with data on average reaction times, arguing that as reaction times correlate with intelligence, they can be used as indices of intelligence (Lynn, 1991; Lynn & Vanhanen, 2002, p. 66). The reaction time data come from papers from the early 1990s that Lynn and co-authors published to document results from samples of nine-year-old schoolchildren in various countries.
Unfortunately, when summarizing these datasets, Lynn misreports some results, omits others and draws conclusions from them that are too strong to be justified by the original sources. Hence a comprehensive and accurate account of Lynn's results has yet to be published. This paper's purpose is to rectify the situation by achieving three goals: cataloguing the papers by Lynn et al. that contain comparative reaction time data; recording where Lynn has misreported those results or failed to cite them; and explaining why interpreting his results as evidence of racial differences in intelligence is dubious. To do so it is necessary to first explain precisely which measurements Lynn and his co-workers took, and how they took them.
The nature of the data
The measurement apparatus Lynn and his colleagues used in each country enabled them to make several kinds of reaction time measurement. This apparatus was a rigid box with a downward-sloping top face, in which face were embedded the buttons and lights used to test the subject. The subject began each reaction time trial by depressing a central home button. Around that button were eight more buttons arranged in a semicircle 30 cm (12 inches) wide, each of these eight outer buttons being next to a small light. At the start of each reaction time trial all of the lights were off; one or more of the lights would then turn on, indicating to the subject that they should lift their finger off the home button and press a particular outer button. The net...