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Two studies examined whether infants' category discrimination in an object-examination task was based solely on an ad hoc analysis of perceptual similarities among the experimental stimuli. In Experiment 1A, 11-month-olds examined four different exemplars of one superordinate category (animals or furniture) twice, followed by a new exemplar of the familiar category and an exemplar of the contrasting category. Group A (N = 39) explored natural-looking toy replicas with low between-category similarity, whereas group B (N = 40) explored artificial-looking toy models with high between-category similarity. Experiment 1B (N = 40) tested a group of 10-month-olds with the same design. Experiment 1C (N = 20) reversed the order of test trials. For Experiment 2 (N = 20), the same artificial-looking toy animals as in Experiment 1 (group B) were used for familiarization), but no category change was introduced at the end of the session. Infants' responses varied systematically only with the presence of a category change, and not with the degree of between-category similarity. This supports the hypothesis that performance was knowledge based.

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Recent studies suggest that even infants attend to others' beliefs in order to make sense of their behavior. To warrant the assumption of early belief understanding, corresponding competences need to be demonstrated in a variety of different belief-inducing situations. The present study provides corresponding evidence, using a completely nonverbal object-transfer task based on the general violation-of-expectation paradigm. A total of n = 36 infants (15-montholds) participated in one of three conditions. Infants saw an actor who either observed an object's location change, did not observe it, or performed the location change manually without seeing it (i.e., variations in the actor's information access). Results are in accordance with the assumption that 15-monthold infants master different belief-inducing situations in a highly flexible way, accepting visual as well as manual information access as a proper basis for belief induction.For more than 25 years it has been assumed that children develop an understanding of others' beliefs around 4 years of age and that younger children do not understand that mental states, such as beliefs, are not direct reflections of the reality but representations that may be true or false (e.g., for a meta-analysis see

This study investigates the effects of attention-guiding stimuli on 4-month-old infants' object processing. In the human head condition, infants saw a person turning her head and eye gaze towards or away from objects. When presented with the objects again, infants showed increased attention in terms of longer looking time measured by eye tracking and an increased Nc amplitude measured by event-related potentials (ERP) for the previously uncued objects versus the cued objects. This suggests that the uncued objects were previously processed less effectively and appeared more novel to the infants. In a second condition, a car instead of a human head turned towards or away from objects. Eye-tracking results did not reveal any significant difference in infants' looking time. ERPs indicated only a marginally significant effect in late slow-wave activity associated with memory encoding for the uncued objects. We conclude that human head orientation and gaze direction affect infants' object-directed attention, whereas movement and orientation of a car have only limited influence on infants' object processing.

T his paper investigates whether preverbal children form categories at different levels of abstraction in any speci c sequence. In a longitudinal study, 20 infants were each tested twice, at 8 and 12 months of age. Half of the children solved a global-level task (animals-furniture), followed by a basic-level task (either dogs-birds, or chairs-tables) during each session. T he other half received the basic-level task only. During familiarisation, all infants freely explored a series of four different exemplars from the same category presented one at a time. Infants saw all objects twice, for a total of eight trials. During the test phase, a new exemplar from the familiar category was presented, followed by a different-category exemplar. At 8 months of age, children discriminated between categories in the global-level task, but failed to do so in the basic-level task. At 12 months of age, infants recognised a category change in the basic-level task, but treated both test items as equally new in the global-level task. These ndings support the hypothesis that infants younger than 1 year of age show a global-tobasic-level shift in category formation.

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