[1] Duke Univ, Dept Evolutionary Anthropol, Durham, NC 27708 USA
[2] Duke Univ, Dept Neurobiol, Durham, NC 27708 USA
[3] Duke Univ, Dept Psychol & Neurosci, Durham, NC 27708 USA
[4] Duke Univ, Ctr Cognit Neurosci, Durham, NC 27708 USA
[5] Duke Univ, Duke Inst Brain Sci, Durham, NC 27708 USA
[6] CNR, Ist Sci & Tecnol Cogniz, I-00197 Rome, Italy
[7] Max Planck Inst Evolutionary Anthropol, Dept Dev & Comparat Psychol, D-04103 Leipzig, Germany
[8] Duke Univ, Dept Biol, Durham, NC 27704 USA
[9] Univ Veracruzana, Inst Neuroetol, Xalapa 91190, Veracruz, Mexico
[10] Liverpool John Moores Univ, Res Ctr Evolutionary Anthropol & Palaeoecol, Liverpool L3 3AF, Merseyside, England
[11] Stanford Univ, Sch Med, Ctr Interdisciplinary Brain Sci Res, Stanford, CA 94305 USA
[12] Stanford Univ, Sch Med, Dept Psychiat & Behav Sci, Stanford, CA 94305 USA
[13] Smithsonian Natl Zool Pk, Ctr Anim Care Sci, Washington, DC 20008 USA
[14] Univ Rochester, Seneca Pk Zoo, Dept Brain & Cognit Sci, Rochester, NY 14620 USA
[15] Univ Rochester, Seneca Pk Zoo, Dept Comparat Med, Rochester, NY 14620 USA
[16] Univ St Andrews, Dept Psychol & Neurosci, St Andrews KY16 9JP, Scotland
[17] Univ Penn, Dept Psychol, Philadelphia, PA 19104 USA
[18] Univ Zurich, Anthropol Inst & Museum, CH-8057 Zurich, Switzerland
[19] Univ Cambridge, Dept Psychol, Cambridge CB2 3EB, England
[20] Univ Calif Berkeley, Dept Psychol, Berkeley, CA 94720 USA
[21] Univ Calif Berkeley, Helen Wills Neurosci Inst, Berkeley, CA 94720 USA
[22] Kyoto Univ, Grad Sch Letters, Kyoto 6068501, Japan
[23] Utah State Univ, Dept Psychol, Logan, UT 84322 USA
[24] Utah State Univ, Wildland Resources, Logan, UT 84322 USA
[25] Univ Kentucky, Dept Psychol, Lexington, KY 40506 USA
[26] Yale Univ, Dept Psychol, New Haven, CT 06520 USA
[27] Univ Fed Paraiba, Dept Engn & Meio Ambiente, BR-58059900 Joao Pessoa, Paraiba, Brazil
[28] Univ York, Dept Psychol, York YO10 5DD, N Yorkshire, England
[29] Think Elephants Int, Stone Ridge, NY 12484 USA
[30] Univ Vet Med Vienna, Messerli Res Inst, A-1210 Vienna, Austria
[31] Wolf Sci Ctr, A-2115 Ernstbrunn, Austria
[32] McGill Univ, Dept Biol, Montreal, PQ H3A 1B1, Canada
[33] Univ Michigan, Dept Anthropol, Ann Arbor, MI 48109 USA
[34] Peking Univ, Dept Psychol, Beijing 100871, Peoples R China