Fig. 3.
Mean percentage correct on the object-choice task for each group in each declarative condition. Performance was evaluated relative to chance (μ = 50%) using one-sample t tests, *p < .05, **p < .01, ***p < .001. Error bars represent standard errors. YNPRC = Yerkes National Primate Research Center of Emory University; GATI = Great Ape Trust of Iowa; LRC=Language Research Center of Georgia State University.