In problem solving, it is thought that working memory is utilized to process information about the problem and maintains its accessibility during the problem solving process. Since working memory has limited storage capacity, it is possible that information in a problem can exceed this limit (called cognitive overload) and interfere with attempts to seek a solution (Sweller, 1988). For this reason, information about a problem is often stored externally (written down) or processed externally (such as with a calculator or computer) in order to free up space in working memory that can be devoted to the task. Also, some skills involved in problem solving can be practiced until they become automatic, which also minimizes the use of working memory capacity.