A main source for the ages
Meta-Analysis of Theory-of-Mind Development: The Truth about False Belief
Henry M. Wellman, David Cross, Julanne King Watson · 2001 · Child Development
- Children
- Children from 178 studies
- Where
- Several countries
- Ages
- Preschool years
- How
- A study that pulled together lots of studies
- What it found
- Across 178 studies and several countries, children went from mostly wrong to mostly right answers during the preschool years, whatever version of the task was used.
- Limits
- We have only read the summary; the ages by year are in the paper's figures, which we haven't yet read.