For the study, researchers from the University of London "included volunteers who took part in several experiments designed to assess the effects of anxiety on their ability to perform such tasks as avoiding distractions when reading a story or solving a series of simple math problems."

In one experiment, the team found that "anxious people took longer to read" a "story because they tended to dwell on the irrelevant words, especially when they believed they would be evaluated on their reading comprehension." In another "experiment, volunteers alternated between multiplication and division problems. Anxious participants took longer to complete the task."

The authors also discovered that "anxious people often perform at a level comparable to those who aren't anxious, but at a greater cost in terms of effort and perhaps long-term stress."