Bulf, H. 1 , Gariboldi, V. 1 , de Hevia, M. D. 2 & Macchi Cassia, V. 1
1 Department of Psychology, University of Milano-Bicocca
2 Laboratoire Psychologie de la Perception, Université Paris-Descartes
Chicks and 7-month-old infants manifest asymmetries in spatial processing when they are required to perform an ordinal task. Chicks showed a leftward bias in locating a target in a series of identical objects on the basis of its ordinal position. Infants showed a preference for left-to-right oriented increasing numerical sequences over the same sequences presented from right-to-left. Here, we investigate whether the infants' mapping between order and left-to-right oriented spatial codes is limited to numerical information, or it holds for non-numerical ordinal information as well. Using a visual habituation paradigm, we tested 7-month-olds' ability to extract an abstract rule (ABB or ABA) from a sequence of shapes presented in a left-to-right or right-to-left spatial orientation. In the test phase, infants were presented with both ABB and ABA sequences, maintaining the same spatial orientation as in the habituation phase. Infants looked longer to the novel sequences only in the left-to-right spatial condition, demonstrating that the extraction of the rule was possible only when sequences were presented from left to right. This finding provides the first evidence of a facilitating effect of oriented spatial codes on infants' rule learning, suggesting that the number-space mapping is not unique to number.