Defining developmental progressions can be an important step in identifying developmental precursors and mechanisms of change, within and across areas of reasoning. In one exploratory study, we examine whether the development of children's thinking about ownership follows a systematic progression wherein some components emerge reliably before…

The frequency and length of games, conflicts, and contingency sequences that took place between toddlers as they got to know one another were studied using archival data. The sample consisted of 28 unfamiliar 20- and 30-month-old toddlers (predominantly White, 16 males) who met separately with each of two other toddlers for 18 play dates. The…

Infants can help and share in the second year of life. However, there is limited knowledge as to variability in these behaviors as a function of target (e.g., caregiver vs. unfamiliar adult) and the influence of caregiver support on infant prosocial behavior. Infants (N = 268, 124 female) at 1-2 years of age (M = 1.47, SD = 0.27) and again at 2-3…

Accurate perception of emotional (facial) expressions is an essential social skill. It is currently debated whether emotion categorization in infancy emerges in a "broad-to-narrow" pattern and the degree to which language influences this process. We used an habituation paradigm to explore (a) whether 14- and 18-month-old infants perceive…

Children who rapidly recognize and interpret familiar words typically have accelerated lexical growth, providing indirect evidence that lexical processing efficiency (LPE) is related to word-learning ability. Here we directly tested whether children with better LPE are better able to learn novel words. In Experiment 1, 17- and 30-month-olds were…

This research examined whether infants tested longitudinally at 10, 14, and 16 months of age (N = 58) showed evidence of perceptual narrowing based on face gender (better discrimination of female than male faces) and whether changes in caregiving experience longitudinally predicted changes in infants' discrimination of male faces. To test face…

Episodic memory involves binding together what-where-when associations. In three experiments, we tested the development of memory for such contextual associations in a naturalistic setting. Children searched for toys in two rooms with two different experimenters; each room contained two identical sets of four containers, but arranged differently.…

This study explored individual variability in the bilingual vocabularies of 65 Maltese children aged 23-27 months (N = 33) and 30-34 months (N = 32). Most of the participants' direct input consisted of Maltese sentences embedding English words. Bilingualism was present at the societal level. Word production was measured through parental report,…

The purpose of this study was to examine the associations between maternal reports of social fear at 24 months and social behaviors with an unfamiliar peer during play at 36 months, using the Actor-Partner Interdependence Model (APIM; Kashy & Kenny, 1999). The APIM model was used to not only replicate previous findings of direct effects of…

This study asked whether children's tendency to imitate selectively (ignore causally unnecessary actions) versus faithfully ("overimitate" causally unnecessary actions) varies across ages and social contexts. In the first experiment, 2-year-olds and 4-year-olds were randomly assigned to play 1 of 3 prior games with a demonstrator: a…

Do infants develop meaningful social preferences among novel individuals based on their social group membership? If so, do these social preferences depend on familiarity on any dimension, or on a more specific focus on particular kinds of categorical information? The present experiments use methods that have previously demonstrated infants' social…

In this article a study is presented of selective affiliation of two- and three-year-old children in the natural situation of Dutch daycare centers. Data of (behavioral) characteristics of 674 pairs of children (dyads) were collected. Multi-level analyses of these dyadic data were conducted and showed that the chance of friendship between two…

The overarching goal of the present study was to trace the development of mirror self-recognition (MSR), as an index of toddlers' sense of themselves and others as autonomous intentional agents, in different sociocultural environments. A total of 276 toddlers participated in the present study. Toddlers were either 16, 17, 18, 19, 20, or 21 months…

Perceptual grouping by luminance similarity and by proximity was investigated in infants with Williams syndrome (WS) aged between 6 and 36 months (visit 1, N=29). WS infants who were still under 36 months old, 8 months later, repeated the testing procedure (visit 2, N=15). Performance was compared to typically developing (TD) infants aged from 2…