Final Answer:
The pre-operational phase, according to Jean Piaget's theory of cognitive development, typically occurs in children between the ages of 2 to 7 years.
Step-by-step explanation:
1. **Jean Piaget's Theory:**
 - *Stages of Cognitive Development:* Piaget identified four stages of cognitive development, with the pre-operational phase being the second stage.
2. **Age Range:**
 - *2 to 7 Years:* The pre-operational phase spans from approximately 2 to 7 years of age. During this period, children develop symbolic thinking, language skills, and engage in pretend play.
3. **Characteristics of the Pre-operational Phase:**
 - *Symbolic Representation:* Children in this stage begin to use symbols, such as words and images, to represent objects and ideas.
 - *Egocentrism:* Egocentric thinking is prominent, where children struggle to consider perspectives other than their own.
 - *Centration:* Children may exhibit centration, focusing on one aspect of a situation while neglecting others.
 - *Lack of Conservation:* Conservation tasks, understanding that quantity remains the same despite changes in appearance, are challenging for children in this phase.
Understanding the age range for the pre-operational phase helps educators, parents, and caregivers tailor learning experiences to support children's cognitive development during this critical period.