Abstract

Understanding of ordinality refers to the ability to appreciate the inherent «greater than» or «less than» relations between values on a given quantitative dimension. In contrast to quantity matching and discrimination, ordinal knowledge in preverbal infants has received little attention. Although such knowledge is typically regarded as emerging in the course of the first year through observation of transformations in the environment, 4-month-old infants have been found capable to represent ordinal information in size-based and number-based sequences provided that magnitude changes involve increasing relations. Here, we investigated 2-day-old infants' ability to discriminate increasing size-based sequences, using the habituation paradigm. Results show that newborns discriminate between the novel and familiar order at test. Together with evidence from older infants and non-human animals, these findings support the view of a continuity at both ontogenetic and phylogenetic levels of the underlying magnitude representation.