Operational momentum and size ordering in preverbal infants

Psychol Res. 2016 May;80(3):360-7. doi: 10.1007/s00426-016-0750-9. Epub 2016 Feb 22.


Recent evidence has shown that, like adults and children, 9-month-old infants manifest an operational momentum (OM) effect during non-symbolic arithmetic, whereby they overestimate the outcomes to addition problems, and underestimate the outcomes to subtraction problems. Here we provide the first evidence that OM occurs for transformations of non-numerical magnitudes (i.e., spatial extent) during ordering operations. Twelve-month-old infants were tested in an ordinal task in which they detected and represented ascension or descension in physical size, and then responded to ordinal sequences that exhibited greater or lesser sizes. Infants displayed longer looking time to the size change whose direction violated the operational momentum experienced during habituation (i.e., the smaller sequence in the ascension condition and the larger sequence in the descension condition). The presence of momentum for ordering size during infancy suggests that continuous quantities are represented spatially during the first year of life.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Child Development / physiology*
  • Cognition / physiology*
  • Concept Formation*
  • Discrimination Learning*
  • Female
  • Fixation, Ocular
  • Humans
  • Infant
  • Male
  • Pattern Recognition, Visual / physiology*
  • Photic Stimulation / methods