The<unk> , one of the most historically influential<unk> es was developed by Jean Piaget, a Swiss Philosopher (1896–1980). His genetic epistemological<unk>  provided many central concepts in the field of<unk> al psychology and concerned the growth of intelligence, which for Piaget, meant the ability to more accurately represent the world and perform logical operations on representations of concepts grounded in interactions with the world. The<unk>  concerns the emergence and construction of schemata — schemes of how one perceives the world — in<unk> al stages", times when children are acquiring new ways of mentally representing information. The<unk>  is considered "constructivist", meaning that, unlike nativist<unk> es (which describe<unk><unk>  as the unfolding of innate knowledge and abilities) or empiricist<unk> es (which describe<unk><unk>  as the gradual acquisition of knowledge through experience), it asserts that we construct our<unk>  abilities through self-motivated action in the world. For his<unk>  of the<unk> , Piaget was awarded the Erasmus Prize.
Piaget divided schemes that children use to understand the world through four main periods, roughly correlated with and becoming increasingly sophisticated with age:
Sensorimotor period (years 0–2)
Preoperational period (years 2–7)
Concrete operational period (years 7–11)
Formal operational period (years 11 and up)
Theory of cognitive development
Emotional intelligence
Speech communication
Child development
Hearing impairment classification
Theory of mind
Attention-deficit hyperactivity disorder classification
Classification of mental disorders