Media type: E-Article Title: Observational learning of discrimination problems by chimpanzees Contributor: Crawford, Meredith P.; Spence, Kenneth W. Published: American Psychological Association (APA), 1939 Published in: Journal of Comparative Psychology, 27 (1939) 1, Seite 133-147 Language: English DOI: 10.1037/h0061696 ISSN: 0093-4127 Origination: Footnote: