Pre-operational

• 2 - 7 years old
• By the age of two, a toddler is mobile and can use language but still lacks reasoning ability
• They understand conservation by the end of this stage, but some pre-operational children didn't understand as much when the counters were pushed together
• Pre-operational children tended to be egocentric, as demonstrated in the three mountains task
• Early in the pre-operational stage children begin to understand class inclusion