Need for cognition
One variable that has been shown to relate to both intelligence and personality traits is the need for cognition (NFC), introduced by Cacioppo and Petty (1982) as a stable personality trait relating to the tendency to engage in and enjoy effortful cognitive activity. Individuals high in NFC tend to seek information when faced with a problem. Such people also think about and reflect on issues, use more rational arguments and are more open to new ideas. Individuals low in NFC, by contrast, tend to use cognitive heuristics and rely on others for information or opinions. NFC is not an ability to think, but an intrinsic motivation to think, and indeed correlates strongly with various measures of intrinsic motivation. Tanaka, Panter and Winborne (1988), for example, identified three factors in the 34-item scale, which they labelled cognitive persistence (enjoyment of engaging in cognitive tasks), cognitive confidence (confidence about engaging in cognitive activities) and cognitive complexity (preference for complex or simple information processing demands).