Alternative spin on phylogenetically inherited spatial reference frames

People make use of different frames of reference (north-south; left-right) to talk about space. To explore the cognitive capacity that children bring to learning spatial language, Haun, Rapold, Call, Janzen, and Levinson (2006) examined children's ability to notice and abstract invariant frames of references across instances. They found that 4-year-olds and non-human great apes often noticed environment-defined allocentric relations and not body-defined egocentric ones, leading them to conclude that preschoolers are ready to learn environment-defined terms (e.g. "uphill"), but not body-defined ones (e.g., "left"). However, such a conclusion may be premature. In four new experiments we demonstrate that the previous findings could be an artifact of specific task constraints. With minor experiment modifications, similar-aged children readily noticed egocentric relations. Reviewing additional research, we provide an account of what makes acquiring frames of reference easy or difficult, and why full mastery of terms like "left" and "right" may take many years under normal circumstances.