Knowledge and Expertise
Although acquiring knowledge in any domain is an important part of the creative process, not all forms of knowledge are well captured by the tests of cognitive ability reviewed earlier. One significant source of individual differences not assessed by traditional measures of cognitive ability is domain-specific knowledge, defined as knowledge of the particular dominant culture (such as occupational and avoca- tional knowledge). Ackerman refers to this knowledge as the "dark matter" of adult intelligence (Ackerman, 2000), an under-appreciated yet crucial determinant of achievement.
Another term for domain-specific knowledge is "expertise." This knowledge takes two forms: procedural knowledge (knowing how to do something, heavily required for athletic domains such as sports and dancing) and declarative knowledge (factual information stored in long-term memory, necessary for more cognitive domains). K. Anders Ericsson and colleagues have studied the development of expertise in a wide variety of domains, including medicine, surgery, software design, professional writing, music, visual arts, acting, ballet, and chess (Ericsson, Charness, Feltovich, & Hoffman, 2006). They have found that mastering the tradition within a particular domain requires very long hours of learning and practice (Ericsson, Krampe, & Tesch-Romer, 1993; Ericsson & Ward, 2007).
Of course, creativity is not mere expertise. An idea is not typically judged as creative by an audience if it constitutes a reasonable extension of domain-specific knowledge. For example, the U.S. Patent
Office will not award patent protection if the invention represents no more than ordinary expertise in a domain. However, given that no work can be completely original (indeed, elements of tradition must always be present), creativity requires the creator to find the right balance between tradition and originality. The creator must be just the right distance ahead of the tradition: Too short and the idea is banal, too long and the idea is outlandish.
Also, the amount of expertise required to obtain world-class expertise varies dramatically between domains, and people differ dramatically in the rate in which they master the domain (Simonton, 1999). What's more, the success of training depends on many more factors than just time spent on task, including motivation, environment, and cognitive factors, such as working memory (Hambrick et al., 2014; S. B. Kaufman, 2013). For example, access to mentors and role models (Simonton, 1975) as well as family resources (think of Johann Sebastian Bach growing up in a family of musicians) likely have a great influence in determining whether training results in creative achievement.
Finally, the importance of accumulated knowledge for creativity is by no means limited to domain-specific expertise. Creative people often call on what they know from other domains—general knowledge—to penetrate problems. Paul Erdos, the celebrated Hungarian mathematician, for example, viewed mathematics as a social endeavor and published with 511 collaborators across almost the entire range of mathematical issues (Baker & Bollobas, 1999). He had knocked around mathematics long enough to know the entire field well enough to bring methods from one domain to bear on others. So general was his knowledge and his influence that almost all mathematicians have "Erdos numbers" to designate the degree of separation from Erdos himself: Someone who never published with Erdos but published with someone who did publish with Erdos has an Erdos number of 2. It is estimated that 90% of the world's academic mathematicians have an Erdos number below 8.