Which psychologist identified four stages of development in reasoning?

The identification of four stages of cognitive development in reasoning is attributed to Jean Piaget. He proposed a theory that outlines how children's thinking evolves through distinct stages as they grow and engage with the world. These stages are sensory-motor, preoperational, concrete operational, and formal operational. Each stage represents a different level of cognitive maturity, indicating how children understand and interact with their environment.

Piaget's framework emphasizes the qualitative changes in thinking that occur as children age, highlighting that their reasoning abilities progress from concrete, hands-on experiences to more abstract thought processes. This approach has been foundational in developmental psychology and education, showcasing how reasoning develops in a structured way across childhood and adolescence.

The other individuals listed in the options have made significant contributions to psychology but are focused on different aspects. For example, Lev Vygotsky emphasized social interactions and cultural context in cognitive development, Albert Bandura is known for his work on social learning theory, and Harlow is recognized for his research in attachment and caregiving behaviors in primates.