Question: who developed the zone of proximal development theory
[{'answer': 'by psychologist Lev Vygotsky', 'provenance': [{'wikipedia_id': '3714452', 'title': 'Zone of proximal development', 'start_paragraph_id': 1, 'start_character': 566, 'end_paragraph_id': 1, 'end_character': 594, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '3714452', 'title': 'Zone of proximal development', 'start_paragraph_id': 1, 'start_character': 401, 'end_paragraph_id': 1, 'end_character': 1155, 'bleu_score': 0.599494373828341, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 3333030584332912372}, 'section': 'Section::::Abstract.'}]}]