performance on IQ tests, now known as the Flynn effect slightly before James Flynn's publications documenting the same phenomenon. A few researchers have called the phenomenon the "Lynn–Flynn effect" as a way of recognizing both their contributions. In a 2013 paper, James Flynn offered his comments on this aspect of the effect's naming: Dysgenics and eugenics, 1996 In Dysgenics: Genetic Deterioration in Modern Populations (1996), Lynn reviewed the history of eugenics and dysgenics, from the early writings of Bénédict Morel and Francis Galton through the rise of eugenics in the early 20th century and its subsequent collapse. As a eugenicist himself, Lynn lists three concerns: deterioration in health, intelligence and conscientiousness. Lynn claims that, unlike modern societies, natural selection in pre-industrial societies favoured traits such as intelligence and "character". According to Lynn, those with greater educational achievement have fewer children, while children with lower IQs come from larger families. Lynn claimed that twin studies provide evidence of a genetic basis for these differences. Lynn proposes that conscientiousness is heritable, and that criminals tend to have more offspring. Lynn agreed with Lewis Terman's comment in 1922 that "children of successful and cultivated parents test higher than children from wretched and ignorant homes for the simple reason that their heredity is better". A review of Dysgenics by W. D. Hamilton, Royal Society research professor in evolutionary biology at the University of Oxford, was published posthumously in 2000. Hamilton wrote a lengthy review stating that Lynn, "discussing the large bank of evidence that still accumulates on heritability of aptitudes and differentials of fertility, shows in this book that almost all of the worries of the early eugenicists were well-founded, in spite of the relative paucity of their evidence at the time". Another review of Dysgenics was written in 2002 by Nicholas Mackintosh, emeritus professor of experimental psychology in the University of Cambridge. Mackintosh wrote that "with a cavalier disregard for political correctness, he argues that the ideas of the eugenicists were correct and that we ignore them at our peril". While recognising that the book provides a valuable and accurate source of information, he criticised Lynn for "not fully acknowledg[ing] the negative relationship between social class and education on the one hand, and infant mortality and life expectancy on the other". He questioned Lynn's interpretation of data. He also points out that according to Lynn's reading of the theory of natural selection, "if