skip to main content skip to footer

Cognitive Performance in the 12-week-Old Infant: The Effects of Birth Order, Birth Spacing, Sex and Social Class NICHD

Lewis, Michael; Gallas, Howard
Publication Year:
Report Number:
ETS Research Bulletin
Document Type:
Page Count:
Subject/Key Words:
National Institute for Child Health and Human Development (NICHD), Birth Order, Cognitive Ability, Infant Behavior, Intelligence Tests, Perception, Performance Tests, Sex Differences, Social Class


Twelve-week-old infants were given a battery of perceptual cognitive tasks. These tasks included the Corman-Escalona Scales of Object Permanence, the Mental Development Index of the Bayley Scales, and an attention task measuring habituation and dishabituation. The data failed to show any sex or social class differences, although the MDI was affected by birth order with first borns showing superior performance. In general these three measures of perceptualcog ability were unrelated. These data are used to question the notion of a "g" factor in infancy and therefore the usefulness of a test of infant intelligence. (29pp.)

Read More