The game show that asks "Are You Smarter Than a Fifth Grader" taps into the natural curiosity many have about how they measure up, intellectually. As it turns out, it's possible to make an educated guess on whether a co-worker or friend might be smarter than you. Taller people are often more successful in school and jobs, and this was initially thought to be related to societal perceptions about height, a bias against shorter people and other intangible factors, but a study showed that taller people perform better on cognitive tests. Birth order is a factor as well. Firstborn children have been shown in studies to have higher IQs than their younger siblings, but this is likely related to increased parental attention.
Other aspects of parenting impact intelligence as well. Babies who were breastfed have higher test scores than those who were bottle-fed with infant formula and tended to go further with their education and make more money in their careers. Staying away from alcohol, smoking, drug use and other unhealthy habits will also result in higher levels of creativity and better performance on mental tasks. Teens who put off their first sexual encounter are more likely to be high achievers academically, as are left-handed people and those who take steps to be less stressed. So, if you know a few facts about someone, you might be able to tell if you could outsmart them.