The four development stages are described in Piaget's theory as:
Sensorimotor stage: from birth to age 2 years (children experience the world through movement and senses and learn object permanence)
Preoperational stage: from ages 2 to 7 (acquisition of motor skills and language)
Concrete operational stage: from ages 7 to 11 (children begin to think logically about concrete events)
Formal operational stage: after age 11 (development of abstract reasoning).
For further information -> http://en.wikipedia.org/wiki/Jean_Piaget
According to Piaget these stages can not be skipped, although some researchers disagree with this. But Piaget does say that the time schedule for passing through the stages can be facilitated by experience. Piaget also notes that there is no guarantee that an individual will pass through all the stages. In most cases (not all) it takes formal instruction in high school and college to break into the highest stage.