Taking development and ecology seriously when comparing cognition: reply to Tomasello and Call (2008).

Not all chimpanzees are captive chimpanzees and not all humans are White middle-class Westerners. In other words, ecological differences during upbringing and when tested are essential when making interspecies comparisons. C. Boesch (2007) suggested that this is too often forgotten when chimpanzees and humans are compared to understand "what makes us human." The comments by M. Tomasello and J. Call (2008) on C. Boesch (2007) illustrate nicely the urgency to take development and ecology seriously. The author presents additional data illustrating how the physical and social ecological conditions experienced by an individual during upbringing influence the development of his or her cognitive abilities. Such influences during the ontogeny are very diverse and can express themselves rapidly or much later in life. Luckily, some recent research has shown how increasing the fairness of cross-species tests increases the performance of the apes.