In biology class, the topic turns to genetics. The professor describes the “Doogie” mouse, named after a 1990s television show starring Neil Patrick Harris as a child genius named Doogie Howser. Doogie mice have a genetic manipulation that makes them smarter than other, genetically normal mice. Your classmate turns to you. “I knew it,” she said. “There’s a ‘smart gene’ after all—some people have it, and some people don’t, and that’s why some people are intelligent and some people aren’t.” What would you tell her about the role genetics play in intelligence? What other factors, besides genes, play an important role in determining an individual’s intelligence?

One of your friends tells you about his sister. “We’re very competitive,” he says. “But she’s smarter. We both took IQ tests when we were kids, and she scored 104 but I only scored 102.” What would you tell your friend about the relationship between IQ scores and intelligence? What do IQ scores really measure?

A speaker visiting your university notes that there are still gender differences in academia; for example, in mathematics departments across the country, women make up only about 26 percent of assistant professors and 10 percent of full professors. One of your classmates notes that the statistic is not surprising: “Girls don’t do as well as boys at mathematics,” he says. “So it’s not surprising that fewer girls choose mathematics-related careers.” Based on what you have read in the text about group differences in intelligence, why might women perform more poorly then men on tests of mathematics or science, even if the groups actually have similar ability?

One of your female cousins has a young son, and she is very proud of the boy’s accomplishments. “He’s very smart,” she says. “I know this because he has a great memory: He gets 100 percent on all his vocabulary tests.” What kind of skills do vocabulary tests measure? Although these skills are important for intelligence, what other abilities contribute to an individual’s overall intelligence?