Data from a random cohort of residents in a 2-county area were used to determine the stability in 2 major dimensions of childhood behavior between 2 generations. The 1st generation was assessed at mean age 7, and their offspring were assessed at age 2 years. Measures were used in latent-variable structural equation models to test the hypotheses. Strong stability in these behavior patterns in the 1st generation was shown between early childhood and a reassessment 8 years later. There was a significant stability between generations in the inhibited behavior pattern but not in the difficult pattern. This relationship was stronger when parents had been assessed at an age closer to that of their toddler offspring. Findings are consistent for mother-offspring, father-offspring, and daughter and son subsamples.

Six-month-old infants' ability to form an abstract category of containment was examined using a standard infant categorization task. Infants were habituated to 4 pairs of objects in a containment relation. Following habituation, infants were tested with a novel example of the familiar containment relation and an example of an unfamiliar relation. Results indicate that infants look reliably longer at the unfamiliar versus familiar relation, indicating that they can form a categorical representation of containment. A second experiment demonstrated that infants do not rely on object occlusion to discriminate containment from a support or a behind spatial relation. Together, the results indicate that by 6 months, infants can recognize a containment relation from different angles and across different pairs of objects.

Two experiments examined infant categorization of containment, support or tight-fit spatial relationships. English-learning infants of 10 months (Experiment 1) and 18 months (Experiment 2) were habituated to four pairs of objects in one of these relationships. They were then tested with one event from habituation, one with novel objects in the familiar relationship, one with familiar objects in a novel relationship and one with novel objects in a novel relationship. Infants at both ages generalized their habituation of the containment relationship to novel objects in this relationship. In the support and tight-fit conditions, the younger infants responded only to the novel objects in the test while the older infants responded to the novel relationship, but only with familiar objects. The results indicate that infants learn to categorize containment prior to support or tight-fit relationships and suggest that infants can recognize a relationship between familiar objects prior to novel objects.

Two experiments explored how infants learn to form an abstract categorical representation of support (i.e., on) when habituated to few (i.e., 2) or many (i.e., 6) examples of the relation. When habituated to 2 pairs of objects in a support relation, 14-month-olds, but not 10-month-olds, formed the abstract spatial category (i.e., generalized the relation to novel objects). When habituated to 6 object pairs in a support relation, infants did not attend to the relation. The results indicate that infants learn to form an abstract spatial category of support between 10 and 14 months and that having fewer object pairs depicting this relation facilitates their acquisition of the abstract categorical representation.Learning to form an abstract categorical representation is an important developmental achievement that allows infants to recognize novel instances of a previously experienced category as familiar. In the case of spatial relations between objects (e.g., one object on another), infants' ability to form an abstract categorical representation allows them to recognize a relation as familiar, regardless of the objects depicting it.

Two experiments explored the effect of linguistic input on 18-month-olds' ability to form an abstract categorical representation of support. Infants were habituated to 4 support events (i.e., one object placed on another) and were tested with a novel support and a novel containment event. Infants formed an abstract category of support (i.e., looked significantly longer at the novel than familiar relation) when hearing the word "on" during habituation but not when viewing the events in silence (Experiment 1) or when hearing general phrases or a novel word (Experiment 2). Results indicate that a familiar word can facilitate infants' formation of an abstract spatial category, leading them to form a category that they do not form in the absence of the word.On one side of the long-standing debate on the relation between thought and language has been the view that language can be a strong force in the development of particular concepts (Gopnik & Choi, 1995;Gopnik, Choi, & Baumberger, 1996;Vygotsky, 1962;Xu, 1999). This view has been particularly prominent in discussions of how children acquire the meanings expressed in relational terms, such as verbs and prepositions (Bowerman & Choi, 2001, with some researchers proposing that language may guide the development of relational concepts (e.g., Bowerman, 1996;Bowerman & Choi, 2001;Gentner & Boroditsky, 2001;Talmy, 1983). Language does guide how young children organize spatial events into language-specific semantic spatial categories (Choi & Bowerman, 1991), raising the question of whether experience with a particular spatial morpheme inspires children to form categories of spatial events that they may not otherwise form. However, a lack of experimental evidence has made the feasibility of this argument difficult to measure. Given that a specific word can facilitate infants' ability to form a category of objects (e.g., Balaban & Waxman, 1997;Waxman & Markow, 1995), it is possible that analogous results could be obtained with infants' ability to form an abstract categorical representation of a spatial relation. To explore this possibility, I examined the effect of linguistic input on infants' ability to form an abstract categorical representation of a spatial relation across two experiments.One reason that language is thought to shape the spatial categories that young children form is the myriad ways in which languages organize spatial events, such as placing a cup on the table or a picture on the wall, into the same or many different semantic categories (Bowerman, 1989(Bowerman, , 1996. Perhaps the most well-known example is the difference between English and Korean (Choi & Bowerman, 1991). English speakers linguistically divide events with containment and support relations into two distinct semantic categories: They label containment events as "in" and support events as "on." In contrast, Korean speakers Correspondence concerning this article should be addressed to Marianella Casasola, Department of Human Development, Cornell University, G38 MVR Hall, Ithaca, NY 1...