title: ANIMAL COGNITION. Comment on "Number-space mapping in the newborn chick resembles humans' mental number line".
abstract: Rugani et al. (Reports, 30 January 2015, p. 534) presented evidence that domestic chicks employ a "mental number line." I argue that the hypothesis testing used to support this claim unjustifiably assumes that domestic chicks are unbiased when choosing between identical stimuli presented to their left and right.
authors.affiliation: Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405, USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Harshaw
mesh_terms: D000818:Animals; D002645:Chickens / Q000502:physiology*; D003071:Cognition; D006801:Humans; D055641:Mathematical Concepts; D008606:Mental Processes; D065855:Spatial Processing