Features of graded category structure: Generalizing the family resemblance and polymorphous concept models

The generalized polymorphous concept account of graded structure in abstract categories

“…They combine a relatively weak internal structure with strong links to external categories. Our results resemble those of Dry and Storms (2010), who applied the generalized polymorphous concept model to account for concrete categories' graded structures. They too found that the contribution of external feature information varied from one category to the other.…”

“…Setting θ to low values emphasizes distinctive features, whereas setting θ to high values emphasizes common features. Dry and Storms (2010) noted that the first and third terms in Eq. (3) are collinear.…”

“…Features that the item shares with other categories (i.e., external features) might also be of importance in determining how representative an item is for the target category. This rationale underlies the generalization by Dry and Storms (2010) of the polymorphous concept model (Hampton, 1979(Hampton, , 1981. Dry and Storms demonstrated how the model can be generalized to include both target and external features.…”

“…These are features that the penguin shares with exemplars of the category of fish and might plausibly have an impact on its perceived representativeness as a bird. Dry and Storms (2010) have made the relevance of external features for typicality and membership judgments more salient by casting the polymorphous concept model in terms of exemplar-category similarity. From the work of Tversky (1977), it has become apparent that both common and distinctive features contribute to similarity.…”

A probabilistic threshold model: Analyzing semantic categorization data with the Rasch model

“…If one had specific hypotheses about the measures that determine an item's position along the latent scale one could test these by expressing the β i 's as a linear combination of these predictors. For instance, according to the generalized polymorphous concept model, the similarity between an item and a category can be expressed as a weighted combination of the number of characteristic features shared by item and category, and the number of features that are distinct to the item (Dry & Storms, 2010). Dry and Storms demonstrated how both common and distinctive feature information play a role in the prediction of items' typicality ratings (i.e., item-category-similarity).…”