Children whose minds wander might have sharper brains, a research suggests. A study has found that people who appear to be often distracted   have more "working memory", giving them the ability to hold a lot of information in their heads and control it cleverly. Children at school need this type of memory on a daily basis for a variety of tasks, such as following teachers' instructions or remembering dictated   sentences. During the study, volunteers were asked to perform one simple task during which researchers kept asking if their minds were wandering. At the end, volunteers measured their working memory capacity   by their ability to remember a series of letters mixed with simple maths questions. Daniel Levinson, a professor at the University of Wisconsin-Madison in the United States, said that those with higher working memory capacity reported "more mind wandering during these simple tasks", but their performance did not _ . The results, published online in the journal Psychological Science, appear to confirm former research that found working memory allows humans to deal with multiple thoughts at the same time. Dr Jonathan Smallwood, of the Max Planck Institute for Human Cognitive and Brain Science in Leipzig, Germany, said, "What this study seems to suggest is that, when surroundings for the task aren't very difficult, people with additional working memory capacity use them effectively to think about other things besides what they're doing." Working memory capacity is also associated with general measures of intelligence, such as reading comprehension and IQ scores. Dr Smallwood added: "Our results suggest the sorts of planning that people do quite often in daily life - when they are on the bus, when they are cycling to work, when they are in the shower - are probably supported by working memory." During the study, the researchers asked the volunteers to   _  .
solve some difficult maths problems retell some dictated sentences follow the teacher's instructions carry out one simple task