One of the things that young children need to learn as they grow up is the concept of ‘Theory of Mind’. This is understanding that other people or children will have different opinions, thoughts, experiences, beliefs, imagination and perceptions than our own. Robert Seyfarth explains a classic ‘Theory of Mind’ experiment in this Youtube video here.
By about 4 years old, children will start to realise that not everyone thinks the same way they do, or that they have the same ideas or motivations. They will be able to understand that they may be hungry, but their friend isn’t. Or that their friends all have different favourite colours.