General knowledge has been defined in differential psychology as "culturally valued knowledge communicated by a range of non-specialist media" and encompassing a wide subject range. This definition excludes highly specialized learning that can only be obtained with extensive training and information confined to a single medium. General knowledge is an important component of crystallized intelligence and is associated with openness to experience. Studies have found that people who are highly knowledgeable in a particular domain tend to be knowledgeable in many. General knowledge is thought to be supported by long-term semantic memory ability.