Operational Momentum During Ordering Operations for Size and Number in 4-Month-Old Infants

Authors

  • Viola Macchi Cassia Orcid
    Department of Psychology, University of Milano-Bicocca, Milan, Italy; NeuroMi, Milan Center for Neuroscience, Milan, Italy
  • Hermann Bulf
    Department of Psychology, University of Milano-Bicocca, Milan, Italy; NeuroMi, Milan Center for Neuroscience, Milan, Italy
  • Koleen McCrink
    Department of Psychology, Barnard College, Columbia University, New York, USA
  • Maria Dolores de Hevia
    Université Paris Descartes, Sorbonne Paris Cité, Paris, France; CNRS UMR 8242, Laboratoire Psychologie de la Perception, Paris, France

Abstract

An Operational Momentum (OM) effect is shown by 9-month-old infants during non-symbolic arithmetic, whereby they overestimate the outcomes to addition problems, and underestimate the outcomes to subtraction problems. Recent evidence has shown that this effect extends to ordering operations for size-based sequences in 12-month-olds. Here we provide evidence that OM occurs for ordering operations involving numerical sequences containing multiple quantity cues, but not size-based sequences, already at 4 months of age. Infants were tested in an ordinal task in which they detected and represented increasing or decreasing variations in physical and/or numerical size, and then responded to ordinal sequences that exhibited greater or lesser sizes/numerosities, thus following or violating the OM generated during habituation. Results showed that OM was absent during size ordering (Experiment 1), but was present when infants ordered arrays of discrete elements varying on numerical and non-numerical dimensions, if both number and continuous magnitudes were available cues to discriminate between with-OM and against-OM sequences during test trials (Experiments 2 vs. 3). The presence of momentum for ordering number only when provided with multiple cues of magnitude changes suggests that OM is a complex phenomenon that blends multiple representations of magnitude early in infancy.