1. Leimgruber KL, Ward AF, Widness J, Norton MI, Olson KR, et al. (2014) Give What You Get: Capuchin Monkeys (Cebus apella) and 4-Year-Old Children Pay Forward Positive and Negative Outcomes to Conspecifics. PLoS ONE 9(1): e87035. doi:10.1371/journal.pone.0087035 Figure 3: Percentage of total trials in which monkeys and children paid forward positive and negative outcomes after receiving positi...