Online research in philosophy

Three experiments with preschool- and young school-aged children (N = 75 and 53) explored the kinds of relations children detect in samples of instances (descriptive problem) and how they generalize those relations to new instances (inferential problem). Each experiment initially presented a perfect biconditional relation between two features (e.g., all and only frogs are blue). Additional examples undermined one of the component conditional relations (not all frogs are blue) but supported another (only frogs are blue). Preschool-aged children did not distinguish (...) between supported and undermined relations. Older children did show the distinction, at least when the test instances were clearly drawn from the same population as the training instances. Results suggest that younger children’s difficulties may stem from the demands of using imperfect correlations for predictions. Older children seemed sensitive to the inferential problem of using samples to make predictions about populations. (shrink)

How do people use past experience to generalise to novel cases? This paper reports four experiments exploring the significance on one class of past experiences: encounters with negative or contrasting cases. In trying to decide whether all ravens are black, what is the effect of learning about a non-raven that is not black? Two experiments with preschool-aged, young school-aged, and adult participants revealed that providing a negative example in addition to a positive example supports generalisation. Two additional experiments went on (...) to ask which kinds of negative examples offer the most support for generalisations. These studies contrasted similarity-based and category-based accounts of inductive generalisation. Results supported category-based predictions, but only for preschool-aged children. Overall, the younger children showed a greater reliance on negative evidence than did older children and adults. Most things we encounter in the world are negative evidence for our generalisations. Understanding the role of negative evidence is central for psychological theories of inductive generalisation. (shrink)