Perception of numerical invariance in neonates.

40 healthy, normal newborn infants were evaluated with reference to their ability to discriminate among visual stimulus arrays consisting of 2 versus 3 or 4 versus 6 black dots. Infants made this discrimination within a habituation/dishabituation paradigm for the small number sets (2 to 3 and 3 to 2) but not for the larger sets (4 to 6 and 6 to 4). We argue that this suggests the ability to abstract numerical invariance from small-set visual arrays and may be evidence for complex information processing during the first week of life.