Math fears subtract from memory, learning.

By about age 12, students who feel threatened by mathematics start to avoid math courses, do poorly in the few math classes they do take, and earn low scores on math-achievement tests. Some scientists have theorized that kids having little math aptitude in the first place justifiably dread grappling with numbers.

That conclusion doesn't add up, at least for college students, according to a study in the June JOURNAL OF EXPERIMENTAL PSYCHOLOGY: GENERAL. On the contrary, people's intrusive worries about math temporarily disrupt mental processes needed for doing arithmetic and drag down math competence, report Mark H. Ashcraft and Elizabeth P. Kirk, both psychologists at Cleveland (Ohio) State University.

Math anxiety exerts this effect by making it difficult to hold new information in mind while simultaneously manipulating it, the researchers hold. Psychologists regard this capacity, known as working memory, as crucial for dealing with numbers.

"Math anxiety soaks up working-memory resources and makes it harder to learn mathematics, probably beginning in middle school," Ashcraft says.

He and Kirk ran three experiments, each with 50 to 60 college students. Experiments included roughly equal numbers of male and female students who cited low, moderate, or high levels of math anxiety on a questionnaire.

In the first experiment, Ashcraft and Kirk found that students with a high level of math anxiety enrolled in fewer math courses, received lower math grades, and scored worse on working-memory tests involving numbers than their peers did.

Math anxiety's disruptive effects on working memory appeared in the next experiment. In a series of trials, students first saw a set of letters to be remembered. They were then timed as they performed a mental addition problem. After solving it, volunteers tried to recall the letters they had seen.

High-math-anxiety students scored poorly on both tasks but especially on the mental addition. Their performance hit bottom on problems that involved carrying numbers, such as 47 + 18. However, when permitted to use pencil and paper during trials, they did as well as students without math worries did, indicating an underlying math competence.

The third experiment found that high math anxiety translates into poorer performance on an unconventional number-manipulation task that also taxed working memory. In some trials, for instance, students had to add 7 to each of four numbers that they briefly viewed, one at a time, and then verbally report the transformations in the proper order.

Earlier studies have found that math anxiety temporarily boosts heart rate and other physical indicators of worry, notes psychologist David C. Geary of the University of Missouri in Columbia. Psychological therapies that reduce math worries improve math performance, he adds.

"Ashcraft's study is the first solid evidence that math-anxious people have working-memory problems as they do math," Geary says.