Spatial scaling is an integral aspect of many spatial tasks that involve symbol-to-referent correspondences (e.g., map reading, drawing). In this study, we asked 3-6-year-olds and adults to locate objects in a two-dimensional spatial layout using information from a second spatial representation (map). We examined how scaling factor and reference…

We investigated whether success in number-conservation and class-inclusion tasks relies on a general ability to inhibit misleading strategies. Two groups of 10-year-olds performed inter-task priming between computerized versions of class-inclusion and number-conservation tasks (Experiment 1). In one group, the class-inclusion task served as a…

The goal of this study was to investigate children's descriptions and evaluations of their reasons for leaving others out of a peer group. A total of 84 children (divided into 7-, 11-, and 17-year-old age groups) provided a narrative account of a time they excluded a peer and were subsequently asked to evaluate their reasons for exclusion. With…

Errors differ in degree of seriousness. We asked whether preschoolers would use the magnitude of an informant's errors to decide if that informant would be a good source of information later. Four- and 5-year-olds observed two informants incorrectly label familiar objects, but one informant's errors were closer to the correct answer than the…

An experimental study investigated the effect of the type of mental verb input (i.e., input with "think", "know", and "remember") on preschoolers' theory of mind development. Preschoolers (n = 72) heard 128 mental verb utterances presented in video format across four sessions over two weeks. The training conditions differed only in the way the…

Children's acquisition of tool use abilities is an important part of development but is not yet well understood. This study compares two modes of tool-use learning, observation and individual haptic experience. Two- and 3-year-olds had haptic experience with tools, observed tool use by others, had both haptic and observational experience, or no…

Humans gather most of their knowledge about the world, including objectively true facts and specific cultural norms, by observing and being taught by others. Some individuals are worthy teachers and objects of imitation, having knowledge of cultural practices and positive intentions to inform. Others are better ignored because they are ignorant,…

Previous research has demonstrated that visual properties of objects can affect shape-based categorization in a novel-name extension task; however, we still do not know how a relationship between visual properties of objects affects judgments in a novel-name extension task. We examined effects of increased visual similarity among the target and…

This study explored factors underlying preschoolers' ability to make future-oriented choices. In a delay-of-gratification choice task, quantity and visibility of the reward was systematically varied. Participants included 90 typically developing children aged 2-4 years. Children made more choices to delay gratification as the quantity of the…

We compared the performance of 3- and 5-year-old children with that of chimpanzees in two tasks requiring collaboration via complementary roles. In both tasks, children and chimpanzees were able to coordinate two complementary roles with peers and solve the problem cooperatively. This is the first experimental demonstration of the coordination of…

This study investigates the relationship between mental-state language and theory of mind in primary school children. The participants were 110 primary school students (mean age = 9 years and 7 months; SD = 12.7 months). They were evenly divided by gender and belonged to two age groups (8- and 10-year-olds). Linguistic, metacognitive and cognitive…

Considerable evidence indicates that shape similarity plays a major role in object recognition, identification and categorization. However, little is known about shape processing and its development. Across four experiments, we addressed two related questions. First, what makes objects similar in shape? Second, how does the processing of shape…

Language plays a critical role in theory of mind (ToM) development, particularly the understanding of false beliefs (FB). Further, there is some evidence that the development of FB is important for metalinguistic development, such as the understanding of homonyms and synonyms. However, there is debate regarding the nature of this relationship.…

We investigated how 3-7-year-olds weigh and coordinate information about specific mental states with social norms in the domain of contextually conventional rules. With increasing age, participants increasingly took into account an actor's mental state to predict that actor's behavior. In a criticism judgment task, 7-year-olds could assign…

Three experiments examined 3- and 5-year-olds' recognition of faces in constant and varied emotional expressions. Children were asked to identify repeatedly presented target faces, distinguishing them from distractor faces, during an immediate recognition test and during delayed assessments after 10 min and one week. Emotional facial expression…