How Numbers Bias Preschoolers' Spatial Search

Numbers often bias adults' spatial performance. Because the direction of this bias (left-to-right versus right-to-left) is culture-specific, it has been assumed that spatial-numeric associations develop with reading practice or schooling. The authors tested this assumption by examining spatial-numeric associations in pre-reading preschoolers. Preschoolers were shown two boxes (sample and matching boxes) subdivided into seven verbally numbered "rooms" (e.g., "the four room"). A "winner" card was revealed in the sample box, and children searched for the "winner" in the matching box (located in the same-numbered room). Preschoolers were faster and more accurate when rooms increased numerically from left-to-right versus right-to-left. This advantage was apparently caused by numbers influencing preschoolers' encoding of spatial locations: Ordering of numbers in the sample box affected preschoolers' search greatly, whereas ordering of numbers in the matching box did not. The authors conclude that numeric effects on spatial encoding develop far too early to be caused by reading practice or schooling.