Visual preference procedures were used to investigate development of perceptually based subordinate-level categorization in 3- to 7-month-old infants. Experiments 1 and 2 demonstrated that 3- to 4-month-olds did not form category representations for photographic exemplars of subordinate-level classes of cats and dogs (i.e., Siamese vs. Tabby,…

This research explored the development of one insight about the mind, namely, the belief that people's trains of thought differ even when they see the same stimulus. In Study 1, 5-year-olds, 9-year-olds, and adults heard stories about characters who saw the same object. Although the older groups predicted the object would trigger different trains…