When reading contemporary manuals and protocols from socially hegemonic areas focused on childhood, it is clear how a notion of child development has become a standard of normality. Central to pedagogy, psychology and pediatrics, this notion suggests that good child development depends on a very specific relation between cognitive and bodily evolution. According to it, body and cognition feed back into each other in a process of progress that, at the age of six, should result in body control and, also, in the ability to construct abstract mental representations. It is precisely this notion that allows these areas to place many children in a category that means a developmental disorder. Drawing on ethnographic research with autistic children, I argue that this notion of child development is not only obviously ableist, but also supported by a reductionist conception of cognition. To do so, I write about an autistic boy who, at four and a half years old, has an infinite abstract memory combined with an unstoppable body. His cognition depends on a body in constant movement or, more than that, running, for him, is a form of cognition. He controls his body, and precisely because of that, he runs to represent the world on his own fashion. By thinking about this boy, or better yet, as I like to understand it, by ethnographically running along with him, I would like to stress some ideas about how anthropology can contribute to an even more inclusive science of mind and cognition by thinking about two questions. I would like to ask how far the notion of child development is based upon the idea of a resting body? And also, how our anthropological perspectives change when we run along with our interlocutors?