Answer: 12 MONTHS OLD.
Explanation: Piagetian refers to any relation to Jean Piaget (1896–1980), Swiss developmental psychologist and philosopher known for his epistemological studies with children. Jean Piaget placed great importance in the education of children.
He described 4 stages of development each with a few subtopics. They are
1) The sensorimotor stage
2) preoperational stage
3) concrete operational stage
4) formal operational stage.
One of the sub stages in the sensorimotor stage is the Tertiary circular reactions, novelty, and curiosity; here children explore new possibilities of objects; they try different things to get different results.