Vygotsky borrowed the terms spontaneous and non-spontaneous from Piaget; however, he included scientific concepts in non-spontaneous and preferred the term everyday concepts to the term spontaneous.

Russian psychologist L.S. Vygotsky worked in the 1920s and 1930s, and devoted a large portion of his book Thought and Speech (Vygotsky, 1986) to the experimental work carried out by him and his colleagues, its purpose being to investigate the development of concepts in school-age children.

The purpose of the experiment reported by Vygotsky in his book Thought and Speech was to discover the role that a word plays and the character of its functional use in the process of concept development. He emphasized the importance of words for the development of a child’s thought processes and his concept development.

Modeling human sentence-processing can help us both better understand how the brain processes language, and also help improve user interfaces. For example, our systems could compare different (computer-generated) sentences and produce ones that are easiest to understand.