A main source for the ages
Effortful control in early childhood: Continuity and change, antecedents, and implications for social development.
Grazyna Kochanska, Kathleen T. Murray, Elena T. Harlan · 2000 · Developmental Psychology
- Children
- About 100 toddlers
- Where
- Iowa, United States
- Ages
- About 2 to 3 years
- How
- Researchers tested the same toddlers twice
- What it found
- Toddlers got much better at waiting and holding back between about 2 years and nearly 3.
- Limits
- We have only read the summary, which doesn't give the shares of children at each age.