One train leaves Station A at 6 p.m. traveling at 40 miles per hour toward Station B. A second train leaves Station B at 7 p.m. traveling on parallel tracks at 50 mph toward Station A. The stations are 400 miles apart. When do the trains pass each other?

Entranced, perhaps, by those infamous hypothetical trains, many educators in recent years have incorporated more and more examples from the real world to teach abstract concepts. The idea is that making math more relevant makes it easier to learn.

That idea may be wrong, if researchers at Ohio State University are right. An experiment by the researchers suggests it might be better to let the apples, oranges and locomotives stay in the real world and, in the classroom, to focus on abstract equations, in this case 40 (t+1) = 400 - 50t, where t is the travel time in hours of the second train.

"The motivation behind this research was to examine a very widespread belief about the teaching of mathematics, namely that teaching students multiple concrete examples will benefit learning," said Jennifer Kaminski, a research scientist at the Center for Cognitive Science at Ohio State. "It was really just that, a belief."

Kaminski and her colleagues Vladimir Sloutsky and Andrew Heckler did something relatively rare in education research: They performed a randomized, controlled experiment. Their results appear in today's issue of the journal Science.

Though the experiment tested college students, the researchers suggested their findings might also be true for math education in elementary through high school, the subject of decades of debates about the best teaching methods.

NEW YORK TIMES