Semantic studies on diagrammatic notations (Barwise & Etchemendy,; Shimojima,; Stenning & Lemon, ) have revealed that the "non-deductive," "emergent," or "perceptual" effects of diagrams (Chandrasekaran, Kurup, Banerjee, Josephson, & Winkler,; Kulpa,; Larkin & Simon,; Lindsay, ) are all rooted in the…

In this article, 41 models of covariation detection from 2 x 2 contingency tables were evaluated against past data in the literature and against data from new experiments. A new model was also included based on a limiting case of the normative phi-coefficient under an extreme rarity assumption, which has been shown to be an important factor in…