Biomedical subjects

Alan M Leslie

Publications and source records attributed to Alan M Leslie.

11 recordsLinked to original sources

PubMed2006

15-month-old infants detect violations in pretend scenarios.

Are 15-month-old infants able to detect a violation in the consistency of an event sequence that involves pretense? In Experiment 1, infants detected a violation when an actor pretended to pour liquid into one cup and then pretended to drink from another cup. In Experiment 2, infants no longer detected a violation when the cups were replaced with objects not typically used in the context of drinking actions, either shoes or tubes. Experiment 3 showed that infants' difficulty in Experiment 2 was not due to the use of atypical objects per se, but arose from the novelty of seeing an actor appearing to drink from these objects. After receiving a single familiarization trial in which they observed the actor pretend to drink from either a shoe or a tube, infants now detected a violation when the actor pretended to pour into and to drink from different shoes or tubes. Thus, at an age (or just before the age) when infants are beginning to engage in pretend play, they are able to show comprehension of at least one aspect of pretense in a violation-of-expectation task: specifically, they are able to detect violations in the consistency of pretend action sequences.

Analysis of Variance↗

PubMed2006

The conceptual underpinnings of pretense: pretending is not 'behaving-as-if'.

The ability to engage in and recognize pretend play begins around 18 months. A major challenge for theories of pretense is explaining how children are able to engage in pretense, and how they are able to recognize pretense in others. According to one major account, the metarepresentational theory, young children possess both production and recognition abilities because they possess the mental state concept, pretend. According to a more recent rival account, the Behavioral theory, young children are behaviorists about pretense, and only produce and recognize pretense as a sort of behavior - namely, behaving 'as-if'. We review both the metarepresentational and Behavioral accounts and argue that the Behavioral theory fails to characterize very young children's abilities to produce and to recognize pretense. Among other problems, the Behavioral theory implies that children should frequently mis-recognize regular behavior as pretense, while certain regular forms of pretend play should neither be produced nor recognized. Like other mental states, pretense eludes purely behavioral description. The metarepresentational theory does not suffer these problems and provides a better account of children's pretense.

Child↗

PubMed2006

A new method for calibrating perceptual salience across dimensions in infants: the case of color vs. luminance.

We report a new method for calibrating differences in perceptual salience across feature dimensions, in infants. The problem of inter-dimensional salience arises in many areas of infant studies, but a general method for addressing the problem has not previously been described. Our method is based on a preferential looking paradigm, adapted to determine the relative salience of two stimuli. We report here on the case of stimuli differing in color and luminance, though the method has wider potential. We were able to determine on a psychophysical curve the point at which a color contrast was equally salient to infants as a given luminance contrast. We then used these calibrated, 'iso-salient' stimuli in an object memory study. Results showed that 6.5-month-old infants noticed a color, but not a luminance, change while tracking an occluded object. Our method should have numerous applications in the study of bottom-up effects on infant attention and visual working memory.

Calibration↗

PubMed2006

Acting intentionally and the side-effect effect.

The concept of acting intentionally is an important nexus where theory of mind and moral judgment meet. Preschool children's judgments of intentional action show a valence-driven asymmetry. Children say that a foreseen but disavowed side effect is brought about "on purpose" when the side effect itself is morally bad, but not when it is morally good. This is the first demonstration in preschoolers that moral judgment influences judgments of whether something was done on purpose (as opposed to judgments of purpose influencing moral judgment). Judgments of intentionality are usually assumed to be purely factual. That these judgments are sometimes partly normative-even in preschoolers-challenges current understanding. Young children's judgments regarding foreseen side effects depend on whether the children process the idea that the character does not care about the side effect. As soon as preschoolers effectively process the theory-of-mind concept "not care that P," children show the side-effect effect.

Affect↗

PubMed2005

A memory span of one? Object identification in 6.5-month-old infants.

Infants' abilities to identify objects based on their perceptual features develop gradually during the first year and possibly beyond. Earlier we reported [Káldy, Z., & Leslie, A. M. (2003). Identification of objects in 9-month-old infants: Integrating 'what' and 'where' information. Developmental Science, 6, 360-373] that infants at 9 months of age are able to use shape information to identify two objects and follow their spatiotemporal trajectories behind occlusion. On the other hand, another recent study suggests that infants at 4-5 months of age cannot identify objects by features and bind them to locations [Mareschal, D., & Johnson, M. H. (2003). The "what" and "where" of object representations in infancy. Cognition, 88, 259-276]. In the current study, we investigated the developmental steps between these two benchmark ages by testing 6.5-month-old infants. Experiment 1 and 2 adapted the paradigm used in our previous studies with 9-month-olds that involves two objects hidden sequentially behind separate occluders. This technique allows us to address object identification and to examine whether only one or both object identities are being tracked. Results of experiment 1 showed that 6.5-month-old infants could identify at least one of two objects based on shape and experiment 2 found that this ability holds for only one, the last object hidden. We propose that at this age, infants' working memory capacity is limited to one occluded object if there is a second intervening hiding. If their attention is distracted by an intervening object during the memory maintenance period, the memory of the first object identity appears to be lost. Results of experiment 3 supported this hypothesis with a simpler one-screen setup. Finally, results of experiment 4 show that temporal decay of the memory trace (without an intervening hiding) by itself cannot explain the observed pattern of results. Taken together, our findings suggest that at six months of age infants can store but a single object representation with bound shape information, most likely in the ventral stream. The memory span of one may be due to immaturity of the neural structures underlying working memory such that intervening items overwrite the existing storage.

Cognition↗

PubMed2005

Belief-desire reasoning as a process of selection.

Human learning may depend upon domain specialized mechanisms. A plausible example is rapid, early learning about the thoughts and feelings of other people. A major achievement in this domain, at about age four in the typically developing child, is the ability to solve problems in which the child attributes false beliefs to other people and predicts their actions. The main focus of theorizing has been why 3-year-olds fail, and only recently have there been any models of how success is achieved in false-belief tasks. Leslie and Polizzi (Inhibitory processing in the false-belief task: Two conjectures. Developmental Science, 1, 247-254, 1998) proposed two competing models of success, which are the focus of the current paper. The models assume that belief-desire reasoning is a process which selects a content for an agent's belief and an action for the agent's desire. In false belief tasks, the theory of mind mechanism (ToMM) provides plausible candidate belief contents, among which will be a 'true-belief.' A second process reviews these candidates and by default will select the true-belief content for attribution. To succeed in a false-belief task, the default content must be inhibited so that attention shifts to another candidate belief. In traditional false-belief tasks, the protagonist's desire is to approach an object. Here we make use of tasks in which the protagonist has a desire to avoid an object, about which she has a false-belief. Children find such tasks much more difficult than traditional tasks. Our models explain the additional difficulty by assuming that predicting action from an avoidance desire also requires an inhibition. The two processing models differ in the way that belief and desire inhibitory processes combine to achieve successful action prediction. In six experiments we obtain evidence favoring one model, in which parallel inhibitory processes cancel out, over the other model, in which serial inhibitions force attention to a previously inhibited location. These results are discussed in terms of a set of simple proposals for the modus operandi of a domain specific learning mechanism. The learning mechanism is in part modular--the ToMM--and in part penetrable--the Selection Processor (SP). We show how ToMM-SP can account both for competence and for successful and unsuccessful performance on a wide range of belief-desire tasks across the preschool period. Together, ToMM and SP attend to and learn about mental states.

Choice Behavior↗

PubMed2005

Developmental parallels in understanding minds and bodies.

A recent article by Onishi and Baillargeon presents evidence that 15-month-old infants attribute false beliefs (FBs) to other people. If correct, it lends dramatic new support to the idea that mental state concepts ("theory of mind") emerge from a specialized neurocognitive mechanism that matures during the second year of life. But it also raises new puzzles concerning the FB task--puzzles that have intriguing parallels in results from infants' reasoning about solid bodies.

Brain↗

PubMed2005

Processing demands in belief-desire reasoning: inhibition or general difficulty?

Most 4-year-olds can predict the behavior of a person who wants an object but is mistaken about its location. More difficult is predicting behavior when the person is mistaken about location and wants to avoid the object. We tested between two explanations for children's difficulties with avoidance false belief: the Selection Processing model of inhibitory processing and a General Difficulty account. Children were presented with a false belief task and a control task, in which belief attribution was as difficult as in the false belief task. Predicting behavior in light of the character's desire to avoid the object added more difficulty in the false belief task. This finding is consistent with the Selection Processing model, but not with the General Difficulty account.

Chi-Square Distribution↗

PubMed2004

Core mechanisms in "theory of mind".

Our ability to understand the thoughts and feelings of other people does not initially develop as a theory but as a mechanism. The "theory of mind" mechanism (ToMM) is part of the core architecture of the human brain, and is specialized for learning about mental states. Impaired development of this mechanism can have drastic effects on social learning, seen most strikingly in the autistic spectrum disorders. ToMM kick-starts belief-desire attribution but effective reasoning about belief contents depends on a process of selection by inhibition. This selection process (SP) develops slowly through the preschool period and well beyond. By modeling the ToMM-SP as mechanisms of selective attention, we have uncovered new empirical phenomena. We propose that early "theory of mind" is a modular-heuristic process of domain-specific learning.

Brain↗

PubMed2004

Mechanisms of belief-desire reasoning. Inhibition and bias.

Biases in reasoning can provide insight into underlying processing mechanisms. We demonstrate a new bias in children's belief-desire reasoning. Children between 4 and 8 years of age were told a story in which a character was mistaken about which of three boxes contained some object. The character wanted to go to one of the boxes, but only if it did not contain the object. In this scenario, the character would be expected to avoid the box where she falsely believed the object to be, but might go to either of the remaining boxes. Though the character was equally likely to go to either box, children were biased to predict that the character would go to the box that contained the object. In a control task, the character had the same desire but did not have a false belief; in this case, children showed no bias, choosing the two correct answers equally often. The observed pattern of bias was predicted by a developmental model of belief-desire reasoning. Competent belief-desire reasoning depends on a process of selection by inhibition in which the best belief content emerges from a set of candidates.

Bias↗

PubMed2004

Who's for learning?

Explore the source record for details and available documents.

Child Development↗