Vygotsky was a Russian psychologist who developed the social constructivist theory. The theory focuses on how social and cultural aspects influence cognitive development. According to Vygotsky, social interaction plays a fundamental role in developing cognition. He believed that community and social learning precede development. Key concepts in Vygotsky's theory include the zone of proximal development, which is the area where guidance allows children to develop skills they will use independently, and the more knowledgeable other, referring to someone with a higher ability level to help the learner. Vygotsky also viewed language as developing from social interactions and believed thought and language merge around age three when they become interdependent.