Rhesus monkeys (Macaca mulatta) map number onto space.
Humans map number onto space. However, the origins of this association, and particularly the degree to which it depends upon cultural experience, are not fully understood. Here we provide the first demonstration of a number-space mapping in a non-human primate. We trained four adult male rhesus macaques (Macaca mulatta) to select the fourth position from the bottom of a five-element vertical array. Monkeys maintained a preference to choose the fourth position through changes in the appearance, location, and spacing of the vertical array. We next asked whether monkeys show a spatially-oriented number mapping by testing their responses to the same five-element stimulus array rotated ninety degrees into a horizontal line. In these horizontal probe trials, monkeys preferentially selected the fourth position from the left, but not the fourth position from the right. Our results indicate that rhesus macaques map number onto space, suggesting that the association between number and space in human cognition is not purely a result of cultural experience and instead has deep evolutionary roots.
Department of Neurobiology and Center for Cognitive Neuroscience, Duke University, Box 90999, Durham, NC 27708, United States. Electronic address: caroline.drucker@duke.edu.
Caroline B
CB
Drucker
Department of Psychology and Neuroscience and Center for Cognitive Neuroscience, Duke University, Box 90999, Durham, NC 27708, United States. Electronic address: brannon@duke.edu.
Elizabeth M
EM
Brannon
D000818:Animals; D003071:Cognition / Q000502:physiology*; D003210:Concept Formation / Q000502:physiology*; D008253:Macaca mulatta; D008297:Male; D009949:Orientation / Q000502:physiology*; D012399:Rotation; D013028:Space Perception / Q000502:physiology*
Monkeys; Numbers; Ordinal representation; SNARC effect; Space