The relationship between intelligence and creativity: On methodology for necessity and sufficiency
Plain English Abstract A classic theory in psychology is that intelligence is necessary but not sufficient for creativity: unintelligent people are only uncreative; but intelligent people may be creative or uncreative. Many other theories in the social sciences invoke the same asymmetric necessary-but-not-sufficient relationship. Whereas the theory is simple enough to state, statistically confirming it—as scientists aim to do with their theories—is a complicated matter, as statistical methods conventional to psychologists are inappropriate for asymmetric relationships. For decades, this methodological problem left researchers stumped, and the present article sheds light on it. In particular, the present article does the following: argues that previous methods purported to statistically confirm the theorized relationship are lacking; proposes a novel model that elucidates the notions of necessity and sufficiency between a pair of variables; and demonstrates this model on a dataset from a published study of intelligence and creativity. Of the two creativity variables analyzed, the classic theory was confirmed for only one of them. It is important that social science researchers carefully think about methodology, as doing so guards against false-positive results in their respective fields.Scientific Abstract On the relationship between intelligence and creativity, a classic theory is that intelligence is necessary but not sufficient for creativity. Graphically, this theory is represented by a triangular shape of bivariate scatter between the two. As conventional linear methods are known to be inappropriate, a long-standing problem has been how to substantiate this theory. One innovation purported to solve this problem is the use of Necessary Condition Analysis (NCA), a method that confirms the relationship on the basis of an empty upper left corner in the scatterplot. The present article elaborates a novel take on this methodological problem. What it takes to account for necessity and sufficiency is tackled, and it is argued that NCA is not an appropriate method. As an alternative, a probability model of creativity as a function of IQ was posited, in particular for double-bounded creativity variables. Using the model proposed, intelligence vs. creativity data from Jauk et al. (2013b) were reanalyzed. A formal hypothesis based on the theorized relationship was supported for one of the two creativity variables analyzed.