Margaret Cobb worked at the Yale University Clinic of Child Development, known as the “Psycho-Clinic” at the time this report was published. Her study was one of the first to use dependent, adoptable children to explore the relationship between nature, nurture, and intelligence. A summary of Cobb’s work appeared in a 1923 book by Arnold Gesell, The Pre-School Child from the Standpoint of Public Hygiene and Education. It was the first mention of adoption in Gesell’s published work.

In her study, Cobb administered mental tests to 200 children referred to the Yale clinic by the Connecticut Department of Child Welfare. She also gathered as much information as possible about their family histories, early environments, and personal traits. The children, who ranged in age from four to eighteen years, resided in three separate institutions at the time of the study. Each was given a brief version of the Stanford-Binet test, which calculated I.Q. (Intelligence Quotient) by dividing each subject’s “mental age” by his or her “chronological age.” The point was to predict the children’s educational and placement “outlooks.”

Cobb’s test results showed that dependent children, as a group, possessed inferior mentality. Their I.Q.s could be plotted on a curve that lagged behind a normal distribution of randomly chosen schoolchildren by about 20 points at all ages, from youngest to oldest. According to Cobb, the Connecticut children were disadvantaged by a combination of flawed heredity, chaotic early home environments, and their sometimes lengthy orphanage stays, but her capsule case histories suggested that the children’s mental limitation was largely eugenic in character. They were genetically inclined to be “feeble-minded.” Unlike later studies, which showed that institutional residence did positive harm to children’s development, Cobb argued that institutions did not influence their intelligence but rather prevented them from becoming useful members of society.

In Gesell’s rendition of Cobb’s study, adoptability and educability were equated. This illustrated two things. First, many would-be adopters placed a premium on knowing something about children’s future potential for schooling. Second, child-placers at the time worried about placement errors called “under-placement” and “over-placement.” (The first referred to giving bright children to dull parents. The second referred to giving dull children to bright parents.) Cobb concluded that a mere 2 percent of the sample had college potential, 7 percent could be expected to finish high school, 17 percent could do some high school work, 35 percent might benefit from vocational training after completing elementary school, 21 percent might finish the fifth or sixth grade, and 18 percent were unsuited for any kind of regular education but would benefit from special training.

Nature-nurture studies conducted by researchers at the Iowa Child Welfare Station in the 1930s would be the most famous to make an optimistic case for adoption by showing that early family placements literally increased children’s I.Q.s. Cobb’s report suggested that disappointment would result if child-placers ever lost sight of the mental limitations that were inherent in many available children. It was, Cobb noted, “a case of like breeding like.”