This 6-wave longitudinal study (2014-2018) of 161 German 5- to 10-year-olds from a midsized city and rural area in southern Germany (89 females, 72 males; predominantly White; mostly middle class) found that scientific-reasoning abilities first develop at 6 years. Abilities were highly stable, with the kindergarten score predicting 25% of…

Both theory of mind (ToM) and executive functioning have been related to children's academic abilities. In a longitudinal study with 112 children, we investigated the influence of these two abilities on children's math and reading performance at 7 years of age. We found that math performance was predicted by concurrent working memory as well as by…

This 5-year longitudinal study investigated advanced theory-of-mind (AToM) development in 161 German 5- to 10-year-olds (89 females, 72 males). Core aspects of AToM developed nonlinearly, with children reaching a milestone at the age of 7 years, around when they attained the conceptual insight that mental states can be recursive. In late…

First-order theory of mind (ToM) development has shown to conform to a Guttman scale, with desire reasoning developing before belief reasoning. There have been attempts to test for internal consistency and scalability in advanced ToM, but not over a broad age range and only with a limited set of tasks. This 2-year longitudinal study (N = 155;…

Early scientific thinking in kindergarten (6-year-olds) was investigated in a large study involving 227 participants. We investigated (1) whether individual differences across 3 scientific-thinking components (experimentation, data interpretation, and understanding the nature of science) are stable across children, (2) whether children's increased…

First-order and advanced theory of mind (ToM and AToM), and their structures and relations were investigated in 229 children aged 5-8 years. ToM was assessed using 6 tasks from the first-order ToM scale, while AToM was measured using an 18-item battery (higher-order false-belief understanding; strange stories; faux pas test; eyes test;…

Do social cognition and epistemological understanding promote elementary school children's experimentation skills? To investigate this question, 402 children (ages 8, 9, and 10) in 2nd, 3rd, and 4th grades were assessed for their experimentation skills, social cognition (advanced theory of mind [AToM]), epistemological understanding (understanding…

Advanced theory-of-mind (AToM) development was investigated in three separate studies involving 82, 466, and 402 elementary school children (8-, 9-, and 10-year-olds). Rasch and factor analyses assessed whether common conceptual development underlies higher-order false-belief understanding, social understanding, emotion recognition, and…