[4] Later, she enrolled in the University of Washington to become an English teacher, but after taking an introductory psychology course she changed her path.
[2] During her years at the University of Washington, she got the opportunity to work as a laboratory assistant in the Gatzert Foundation for Child Welfare.
In 1928, Bayley moved to the University of California, Berkeley, to work in the Institute of Child Welfare.
In 1954, she went to the National Institute of Mental Health in Bethesda, Maryland, where she worked on child development in the Laboratory of Psychology.
[2][3] The children were white, raised in English-speaking homes within the Berkeley area, and were of above average socioeconomic status.
An analysis of trends in the data was then conducted, with particular reference to the age of developments, as well as a correlational investigation of relating factors.
Subsequent assessments were conducted at the Institute for Child Welfare, as well as at home visits, pediatric centers, and at play-based field group outings.
Participants completed the California Infant Scale of Motor Development, as well as examinations of footprint records.
Physiological tests assessed exercise and exertion abilities, the galvanic skin reflex, and metabolism.
[citation needed] Other factors Bayley considered vitally important to development were parenting attitudes and behaviors.
[citation needed] Examinations of x-rays and physiological growth led Bayley to become the first scientist to recognize the predictability of adult height based on infant size.
[citation needed] Additionally, Bayley discovered no gender differences in terms of physical and psychological development.
[6] The purpose of the BSID-III is to gain further information about a child's developmental milestones and abilities, as well as to intervene at an early age if a learning disability presents itself.
These changes include: age range, norms altered to function more successfully with modernization, and greater validity and reliability.
The Mental Scale presented in BSID-II assesses children using a normalized standardized scoring system – the Mental Development Index (MDI) – and a standard scoring system – the Psychomotor Development Index (PDI).
The Behavior Rating Scale presents a numerical assessment of a child's attention, arousal, orientation/engagement, emotional regulation, and motor ability.
Environmental correlates of mental and motor development: A cumulative study from infancy to six years.