The following table shows the various milestones in early childhood with their significance.
| Advance | Significance |
|---|---|
| Use of symbols | Children do not need to be in sensory motor contact with an object, person or event in order to think about it. They can imagine that objects or people have properties other than they actually observe. |
| Understanding of identities | Children are aware that superficial alterations do not change the nature of things. |
| Understanding cause and effect | Children realise that events have causes. |
| Ability to classify | Children organise objects, people and events into meaningful categories. | Understanding of numbers | Children can count and deal with quantities. |
| Empathy | Children become more able to imagine how others might feel. |
| Aware of mind | Children become more aware of mental activity and the functioning of the mind. |