Although some studies have suggested inverse relationships between psychopathy and intelligence, including with regards to verbal IQ, Hare and Neumann state that a large literature demonstrates at most only a weak association between psychopathy and IQ, noting that the early pioneer Cleckley included good intelligence in his checklist due to selection bias (since many of his patients were "well educated and from middle-class or upper-class backgrounds") and that "there is no obvious theoretical reason why the disorder described by Cleckley or other clinicians should be related to intelligence; some psychopaths are bright, others less so". Studies also indicate that different aspects of the definition of psychopathy (e.g. interpersonal, affective (emotion), behavioral and lifestyle components) can show different links to intelligence, and the result can depend on the type of intelligence assessment (e.g. verbal, creative, practical, analytical).[1][2][3][76]