Researchers have long known that going to school boosts IQ. The question is whether it makes people smarter by building mental horsepower, by adding to students’ database of knowledge and skills, or some of each component. Recent research published in Psychology and Aging shows that people who stay in school for a longer part of their lives are no faster at simple mental judgements (like line comparison) than their less-schooled counterparts. Other research published in Psychological Science shows that high-performing schools do little to boost kids’ mental horsepower. Instead, schooling makes students smarter largely by increasing what they know, both factual knowledge and specific mental skills like analyzing historical documents and learning procedures in mathematics.
This view of schooling carries two implications. If the benefit of schooling comes from the content learned, then it’s important to get a better understanding of what content will be most valuable to students later on in their lives. The answers may seem intuitive, but they’re also subjective and complex. A student may not use plane geometry, solid geometry, or trigonometry, but studying them may improve her ability to mentally visualize spatial relationships among objects, and that may prove useful for decades in a variety of tasks.
The aforementioned research also implies that the sequence of learning is as important as content. Revisiting subjects can protect against forgetting, and sustained study over several years can help make certain knowledge permanent. Thus, when thinking about what expect students to learn, it’s not enough that content be “covered.” Evidence suggests that a student must use such content in his or her thinking over several years in order to remember it for a lifetime.
Traditionally, some educators subscribed to the notion that it doesn’t much matter what students study, as long as it’s hard and they don’t like it. Through the early 20th century, educational theorists believed students should study Latin not because it was a useful language, but because studying it trained the brain to think logically. Although this theory was discarded in the 1920s, the 21st-century version arguably holds that technology has rendered memory unnecessary; what matters is learning to think. Both depict the mind as an all-purpose muscle that gains strength irrespective of the tasks used to exercise it. And both theories, it seems, are flawed.
Education-policy debates tend to focus on structural issues—things like teacher quality, licensure requirements, and laws governing charter schools. But research on human memory indicates that academic content and the way it is sequenced—i.e., curriculum—are vital determinants of educational outcomes, and they’re aspects that receive insufficient attention. In other words, perhaps what matters most after all isn’t mental exercise.