What exactly does the term intelligence mean? Intelligence is defined as the ability to acquire and apply knowledge and skills. Does birth order influence intelligence? According to researchers, there is some evidence to show that birth order actually affects intelligence; however, critics remain skeptical about this and argue that the evidence is inconclusive and partial (Carey, 2007). The relationship between birth order and intelligence has been an ongoing scientific debate dating back to the late 1800s. Francis Galton, an English scientist, published a book in 1874 in which he recorded the lives of 180 notable men in science. Galton collected birth order data on 99 subjects and reported that 48% were “firstborn or only children.” Galton eliminated females from his studies because, in theory, the subject could be the firstborn and fifth child if all of his older siblings were females. Studies were carried out on 314 eminent people who supported Galton's theory; these studies confirmed that 46% of them were firstborns and were among the Nobel Prize winners w...