Nancy Bayley

Nancy Bayley was born and reared in The Dalles, Oregon, and died in Carmel, California. In the history of developmental psychology, few other individuals loom so large.

After grade school and high school in her home town, Bayley attended the University of Washington in Seattle. She planned to become an English teacher but changed to psychology after taking an introductory class taught by Edwin Guthrie, a leader in the psychology of learning. She earned her BS and MS degrees from the University of Washington in 1922 and 1924, respectively. Bayley studied the construction of performance tests for preschool children, a project prefiguring her later work on the development of intelligence. For her PhD, awarded in 1926 from the University of Iowa, she conducted one of the first studies of children’s fears using the galvanic skin response.

From 1926 to 1928, Bayley taught at the University of Wyoming and then joined the Institute of Child Welfare (now Institute of Child Development) at the University of California at Berkeley as a research associate. There, she began what became known as the Berkeley Growth Study, a landmark longitudinal investigation on a large sample of healthy infants born in 1928 and 1929. Over the next half-century, Bayley and her colleagues followed these individuals as they grew from infancy to middle age. The work yielded important discoveries about physical, motor, and mental development; variability and individual differences; the relation of mental performance to environmental factors including socioeconomic factors such as parental education; and the predictability of later mental and physical status from child scores. It remains a treasure trove for scholars today. It also helped advance the study of adult development and the effects of historical forces on child development, including World War II and the Korean War. Over this period, Bayley also developed the Bayley Scales of Motor and Mental Development, still acknowledged as providing the best standardized measures of infant development and used throughout the world.

In 1954, Bayley moved to Bethesda, Maryland, to become  chief  of  the  section  in  child  development at the National Institute of Mental Health. Her many accomplishments there included participation in the National Collaborative Perinatal Project for the study of cerebral palsy and other disorders. In 1964, she  returned to Berkeley, where she continued her studies of individuals from her growth study.

Bayley’s  many  honors  and  awards  include  the G. Stanley Hall Award (1971) for outstanding contributions to developmental psychology, the Presidency of Division 7 (developmental psychology) of the American Psychological Association (1953–1954), and the Gold Medal from the American Psychological Foundation (1982). Throughout her long and distinguished career, Bayley sought to apply “scientific knowledge in the interests  of  human  welfare  and  happiness”  (1956, p. 121). She succeeded, and we are all the richer for it.


  1. Bayley, (1926). Performance tests for three-, four-, and fiveyear-old children.  Journal  of  Genetic  Psychology,  33,435–454.
  1. Bayley, N. (1956). Implicit and explicit values in science as related to human growth and dev Merrill-Palmer Quarterly, 2, 121–126.
  2. Bayley, N., & Schaefer, E. S. (1964). Correlations of maternal and child behaviors with the development of mental abilities: Data from the Berkeley Growth Study. Monographs of the Society for Research in Child Development, 29(6, Serial No. 97), 1–80.