Edmund Gettier is Professor Emeritus at the University of Massachusetts, Amherst. This short piece, published in 1963, seemed to many decisively to refute an otherwise attractive analysis of knowledge. It stimulated a renewed effort, still ongoing, to clarify exactly what knowledge comprises.

It has been found that children appreciate the limited substitutability of co-referential terms in opaque contexts a year or two after they pass false belief tasks (e.g. Apperly and Robinson, 1998, 2001, 2003). This paper aims to explain this delay. Three- to six-year-old children were tested with stories where a protagonist was either only partially informed or had a false belief about a particular object. Only a few children had problems predicting the protagonist’s action based on his partial knowledge, when (...) he was only partially informed about a property of the desired object (e.g. he knew that it was a Lego® block, but not that it was a red Lego® block). But many had problems making the correct action prediction when he was only partially informed about dual identities (e.g. he knew it was a dog, but not that it was also an eraser). About as many children made an incorrect action prediction for partial knowledge problems involving dual identity as answered higher-order belief questions incorrectly. In contrast many more children answered first-order false belief questions correctly, as many as correct action predictions when the protagonist was partially informed about a property of an object. The results support the claim that children have a specific problem with dual identity, rather than a broader problem representing partial knowledge. (shrink)

We provide a cognitive analysis of how children represent belief using mental files. We explain why children who pass the false belief test are not aware of the intensionality of belief. Fifty-one 3½- to 7-year old children were familiarized with a dual object, e.g., a ball that rattles and is described as a rattle. They observed how a puppet agent witnessed the ball being put into box 1. In the agent’s absence the ball was taken from box 1, the child (...) was reminded of it being a rattle, and emphasising its being a rattle it was put back into box 1. Then the agent returned, the object was hidden in the experimenter’s hands and removed from box 1, described as a ‘‘rattle,” and transferred to box 2. Children who passed false belief had no problem saying where the puppet would look for the ball. However, in a different condition in which the agent was also shown that the ball was a rattle they erroneously said that the agent would look for the ball in box 1, ignoring the agent’s knowledge of the identity of rattle and ball. Their problems cease with their mastery of second-order beliefs. Problems also vanish when the ball is described not as a rattle but as a thing that rattles. We describe how our theory can account for these data as well as all other relevant data in the literature. (shrink)

Mental-content verbs such as think, believe, imagine and hope seem to pose special problems for the young language learner. One possible explanation for these diYculties is that the concepts that these verbs express are hard to grasp and therefore their acquisition must await relevant conceptual development. According to a diVerent, perhaps complementary, proposal, a major contributor to the diYculty of these items lies with the informational requirements for identifying them from the contexts in which they appear. The experiments reported here (...) explore the implications of these proposals by investigating the contribution of observational and linguistic cues to the acquisition of mental predicate vocabulary. We Wrst demonstrate that particular observed situations can be helpful in prompting reference to mental contents, speciWcally, contexts that include a salient and/or unusual mental state such as a false belief. We then compare the potency of such observational support to the reliability of alternate or concomitant syntactic information (e.g., sentential complementation) in tasks where both children and adults are asked to hypothesize the meaning of novel verbs. The Wndings support the eYcacy of false belief situations for increasing the saliency of mental state descriptions, but also show that.. (shrink)

Developmental psychology currently faces a deep puzzle: most children before 4 years of age fail elicited-response false-belief tasks, but preverbal infants demonstrate spontaneous false-belief understanding. Two main strategies are available: cultural constructivism and early-belief understanding. The latter view assumes that failure at elicited-response false-belief tasks need not reflect the inability to understand false beliefs. The burden of early-belief understanding is to explain why elicited-response false-belief tasks are so challenging for most children under 4 years of age. The goal of this (...) article is to offer a pragmatic framework whose purpose is to discharge this burden. (shrink)

False belief tasks have enjoyed a monopoly in the research on children’s development of a theory of mind. They have been granted this status because they promise to deliver an unambiguous assessment of children’s understanding of the representational nature of mental states. Their poor cousins, true belief tasks, have been relegated to occasional service as control tasks. That this is their only role has been due to the universal assumption that correct answers on true belief tasks are inherently ambiguous regarding (...) the level of the child’s understanding of mental states. It has also been due to the universal assumption that nothing in the child’s developing theory of mind would lead to systematically incorrect answers on true belief tasks. We review new findings that 4- and 5-year-olds do err, systematically and profoundly, on the true belief versions of all the extant belief tasks. This reveals an intermediate level of understanding in the development of children’s theory of mind. Researchers have been unaware of this intermediate level because it produces correct answers in false belief tasks. A simple two-task battery—one true belief task and one false belief task—is sufficient to remove the ambiguity from each task. The new findings show that children do not acquire an understanding of beliefs, and hence a representational theory of mind, until after 6 years of age, or 2 years later than most developmental psychologists have concluded. This raises the question of how to interpret other new findings that infants are able to pass false belief tasks. We review these new infant studies, as well as recent studies on chimpanzees, in light of older children’s failure on true belief tasks, and end with some speculation about how all of these new findings might be reconciled. (shrink)

Russian translation of Gettier E. L. Is Justified True Belief Knowledge? // Analysis, vol. 23, 1963. Translated by Lev Lamberov with kind permission of the author.