The term metamemory is often used to describe an individual's knowledge of the contents of his or her own memory. The most frequently used example of this is knowing that you don't know something. Researchers have found that when given a two choice test in which subjects can either respond that a) they know the answer to the question or b) they don't know the answer to a question, their reaction times are much shorter for those items they are sure that they don't know (perhaps, for example, What is the name of the largest food market in Kabul?) than those that they might know (e.g. What is the address of the closest coffee shop?).