Question: who introduced the term in group and out group
[{'answer': 'Henri Tajfel', 'provenance': [{'wikipedia_id': '2533750', 'title': 'Ingroups and outgroups', 'start_paragraph_id': 2, 'start_character': 36, 'end_paragraph_id': 2, 'end_character': 48, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '2533750', 'title': 'Ingroups and outgroups', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 501, 'bleu_score': 0.910106621472026, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 921433982727068461}, 'section': 'Section::::Abstract.'}]}]