Knowing other people like different things
By about 18 months, toddlers in a lab study gave an adult the food she liked, even when they preferred a different one. Younger toddlers gave her what they liked themselves. Answering a question about it in words comes later, around age 3.
We haven't yet found studies that measured the age when most children start. The sections below say what is known.
How sure are we?
Not sure yet. The studies we've read so far don't give the age when half of children understand this. How we know this
What it’s a sign of
Your child is learning that other people have their own likes and wants, an early step in understanding other minds.
The toddler food game and the story question for preschoolers differ by more than a year, because one needs only a choice of food and the other a spoken answer. In the United States, Australia, China and Turkey, this was the first of these ideas children learned.
We don't yet know the age by which most children understand this. The tables that would show it haven't been read yet.
A classic study on this
Early reasoning about desires: Evidence from 14- and 18-month-olds.
Betty M. Repacholi, Alison Gopnik · 1997 · Developmental Psychology
- Children
- Not given in the summary we read
- Where
- Not given in the summary we read
- Ages
- 14 and 18 months
- How
- Researchers tested toddlers in a lab
- What it found
- When an adult showed she liked broccoli and disliked crackers, 18-month-olds gave her broccoli, even if they preferred crackers. 14-month-olds gave her what they liked themselves.
- Limits
- We have only read the summary, which doesn't give how many toddlers took part or how many did it.
A main source for the ages
Sequential Progressions in a Theory-of-Mind Scale: Longitudinal Perspectives
Henry M. Wellman, Fang Fuxi, Candida C. Peterson · 2011 · Child Development
- Children
- About 400 children
- Where
- The United States, Australia and China
- Ages
- About 3 to 6 years
- How
- Researchers tested children with five short story tasks
- What it found
- Children learned these ideas in the same order. Children whose only success was knowing that people like different things were about 3½ on average; those who also understood untrue beliefs were about 5.
- Limits
- These are average ages of children at each step, not the age when half of children get there. It pools earlier studies by the same research group.
A main source for the ages
Scaling of Theory-of-Mind Understandings in Chinese Children
Henry M. Wellman, Fang Fuxi, David Liu, Liqi Zhu, Guoxiong Liu · 2006 · Psychological Science
- Children
- About 140 children in Beijing, compared with about 135 in the United States and Australia
- Where
- China, the United States and Australia
- Ages
- About 3 to 6 years
- How
- Researchers tested children with short story tasks
- What it found
- Chinese children learned these ideas in nearly the same order, and knowing that people like different things came first in both groups.
- Limits
- We have only read the summary; the ages are in the tables.
A main source for the ages
Sequence of theory‐of‐mind acquisition in Turkish children from diverse social backgrounds
Bilge Selçuk, Kimberly A. Brink, Müge Ekerim-Akbulut, Henry M. Wellman · 2018 · Infant and Child Development
- Children
- About 260 children
- Where
- Five cities in Turkey, from different backgrounds
- Ages
- About 4½ on average
- How
- Researchers tested children with short story tasks
- What it found
- Turkish children learned these ideas in the same order, starting with knowing that people like different things.
- Limits
- We have only read the summary; the ages are in the tables.
If you’re worried about your child, talk to your child and family health nurse or GP.
Last checked 2 November 2026