%0 Journal Article %A Warneken, Felix %A Tomasello, Michael %+ Department of Developmental and Comparative Psychology, Max Planck Institute for Evolutionary Anthropology, Max Planck Society Department of Developmental and Comparative Psychology, Max Planck Institute for Evolutionary Anthropology, Max Planck Society %T Extrinsic rewards undermine altruistic tendencies in 20-month-olds : %G eng %U https://hdl.handle.net/11858/00-001M-0000-000F-FCAE-5 %F EDOC: 397208 %D 2008 %J Developmental Psychology %V 44 %N 6 %& 1785 %P 1785 - 1788