Vol. 6, No.1
A good "number sense" in a 14-year-old correlates strongly with high scores in school math all the way back to kindergarten. Assistant professors of psychological and brain sciences Justin Halberda and Lisa Feigenson, working with Michele Mazzoco at the School of Medicine, set out recently to test whether a basic, seemingly innate number sense had any bearing on the formal math children learn in school.
So they asked 64 14-year-olds to look at flashing groups of yellow and blue dots on a computer screen and estimate which dots were more numerous. The results helped the researchers ascertain the accuracy of each teen's individual number sense. It's the same kind of sense people use when they very quickly estimate the number of people in a subway car or bus, Halberda says.
Looking at the teenagers' performance in school math every year back to kindergarten, Halberda and his colleagues found that students with a more acute number sense had performed at a higher level in math than those who showed weaker number sense, even controlling for general intelligence and other factors.
"What this seems to mean is that the very basic number sense that we humans share with animals is related to the formal mathematics that we learn in school," Halberda concludes. "The number sense we share with the animals and the formal math we learn in school may interact and inform each other throughout our lives."
Test your own number sense online at: http://tinyurl.com/numbersense.
You're about to leave work at the end of the day when your cell phone rings: It's your spouse, asking you to pick up a gallon of milk on the way home. Before you get out the door, your spouse calls again and asks you to stop by the hardware store, too. Based on your knowledge of the area and rush hour traffic, you decide to get the milk first and the toilet plunger second. But whoops! The phone rings again. This time it's your boss, asking you to work late. That means another change in plans. How exactly does your brain switch so elegantly and quickly from one well-entrenched plan to a new one in reaction to a sudden change in circumstances? In the milk-plunger-boss scenario, do you simply remember a list of streets and turns, or do you remember a more abstract set of "rules" governing the web of relationships between the items you want to buy, your driving route, and your relationships with your spouse and boss?
The answer: both. Susan Courtney, associate professor of psychological and brain sciences, says two different areas of the brain are responsible for the way human beings handle complex sets of "if-then" rules. Courtney and her research team, including graduate student Caroline Montojo, discovered that the prefrontal cortex—just beneath the forehead—and the parietal cortex—near the back of the brain—store different kinds of memories and information, providing "clues about how the human brain accomplishes complex, goal-directed behaviors that require remembering and changing abstract rules." The new research has implications for better understanding psychiatric diseases such as schizophrenia, obsessive-compulsive disorder, and attention deficit disorder—conditions in which a person's ability to remember and change rules is impaired, Courtney says.