The Minnesota Adoption Transpiration Study checks the IQ test scores of 130 black or interracial children adopted by white families benefited. The purpose of this study was to determine the contribution of environmental and genetic factors to the poor performance of black children on IQ tests compared with white children. Initial studies were published in 1976 by Sandra Scarr and Richard A. Weinberg. A follow-up study was published in 1992 by Richard Weinberg, Sandra Scarr and Irwin D. Waldman. Another related study investigated the social adjustment in sub-samples of black children who were adopted published in 1996. One of the research findings was that black children's IQs adopted by white families did not differ significantly from children's skin blacks raised by their biological parents..
Video Minnesota Transracial Adoption Study
Background and study design
On measures of cognitive ability (IQ test) and school performance, black children in the US have worse performance than white children. At the time of the study, the gap in average performance between the two groups of children was about one standard deviation, which is equivalent to about 15 IQ points or 4 grade levels at high school graduation. Thus, the average IQ score of black children in the US is about 85, compared with an average score of 100 white children. No bias can be detected because test or administration constructs have been found, although this does not rule out other biases. The gap is functionally significant, making it an important field of study. The Minnesota Transracial Adoption Study tries to answer whether the gap is mainly due to genetic factors or whether it is primarily caused by environmental and cultural factors.
The study was funded by the Grant Foundation and the National Institute of Child Health and Human Development.
By examining the cognitive abilities and school performance of both black and white children adopted into white families, the study was intended to separate the genetic factors from raising conditions as a causal influence in the gap. "Trans racial adoption is a human analogue of cross-coaching design, commonly used in animal behavioral genetic studies.... There is no question that adoption is a major intervention" (Scarr & Weinberg, 1976, p.676).
Scarr and Weinberg studied black/white, Asian, native-American, and black/white mixed breeds adopted by upper-middle-class white families in Minnesota. The average IQ of parents who adopted more than one standard deviation above the 100 population averages. The biological children of these parents were also tested. The adopted children's sample is selected by qualified parents who contact the researcher to participate after the bulletin call. The geographic origin of adopted children is not uniform. All but one adopted white child is adopted in the country. Black and interracial children come from twelve states; Asian children and native Americans come from Minnesota as well as from Korea, Vietnam, Canada and Ecuador.
As Scarr & amp; Weinberg (1976) notes, the transgans adoption study only controls for the family environment, not the social environment. For example, socially identifiable children as black can still be subject to racial discrimination despite being raised by white parents. However, it was previously known that adoption into upper middle class white families had a positive influence on IQ and school performance of white children.
This study shows significant differences in patterns of adoption of mixed black/white and black mixed children as noted by Scarr and Weinberg (1976):
It is important to note, however, that the group also differed significantly (p <.05) in the history of their placement and natural mother education. Children with two older blacks were significantly older on adoption, had been in their adoptive homes a shorter time, and had experienced a large number of preadoption placements. The natural parent of the black/black group is also on average one year less educated compared to the black/white group, which shows the average difference between groups in intellectual ability. There is also a significant difference between adopted black/black and black children in fathers education and maternal IQ.
Maps Minnesota Transracial Adoption Study
Results
Children were first tested in 1975 at the age of 7 years. In 1985, 196 of the original 265 children were retested at the age of 17 years.
The adopted parents of 12 interracial children mistakenly believed that their adopted children had two black parents. The average IQ of 12 children was not significantly different from the score of 56 religious children correctly classified by their adoptive parents as having one black parent and one white parent.
Some have suggested that different pre-adoption experiences, including age at adoption, explain racial patterns in outcomes. Lee (2009) argues against this interpretation, suggesting that there is no evidence from other studies that variables such as age at adoption have an effect on IQ that lasts until late adolescence. In a study in Minnesota, the proportion of IQ variants associated with pre-adoption variables decreased from 0.32 to 0.13 between ages 7 and 17. Lee further demonstrated that causality can run from IQ and other behavioral variables to differences in pre- adoption more than the other way around, and that race itself as a visible characteristic may have influenced the pre-adoption experience.
The difference in mean IQ scores between tests at age 7 and tests at age 17 years, seen in all groups, may be due to the use of different IQ tests. The original study used the Stanford-Binet Form L-M, WISC or WAIS tests, depending on age, whereas follow-up was used WISC-R or WAIS-R. Weinberg, Scarr, and Waldman explain the effects of this change in testing:
Decreases in IQ scores have been documented when individuals are retested on the revised form of the original size, as well as when the tests used in the first administration were normalized earlier than the tests used in subsequent administration (see Flynn, 1984, for review). For example, the reduction in Full-Scale IQ scores from WAIS to WAIS-R averaged 6.8 points in a number of studies (reviewed by Sattler, 1988) and 7.5 points in samples 72 35- to 44-year olds were tested as part of standardization WAIS-R (Wechsler, 1981). Here is a combination of tests used for adoptive parents in our study.
Furthermore, the data needed to be corrected for the Flynn effect as stated by Ulrich Neisser:
Everyone involved in this debate is well aware that such a comparison should be corrected for the Flynn effect: The average score on all standard IQ tests seems to increase steadily at about 0.3 points per year. In the Minnesota study, where the tests used in follow-up were generally not the same as the first given test, the correction was complicated and had to be done individually. Until they have been made-Waldman et al. reported that those in the crude development figures as above are relatively insignificant.
The data corrected for the Flynn effect was published in 2000 by John Loehlin at the Handbook of Intelligence .
Analysis of structured interviews at ages 7 and 17 reported by (DeBerry, Scarr & Weinberg 1996) found that about half of the adopted black children had difficulty adjusting. They have difficulty being competent in the orientation of European and African-American reference groups but have a stronger affinity with Europeans than with African-American groups. Stronger identification with one or another group predicts better adjustment.
Interpretation
Scr & amp; Weinberg (1976) interprets results from age 7 indicating that racial group differences in IQ can not be inferred because of confusing research. They note, however, that research shows that cross-race adoption has a positive effect on black foster children. To support this interpretation, they drew particular attention to the finding that the average IQ of "socially classified" black children is greater than the average white American. Follow-up data were collected in 1986 and Weinberg et al. published their findings in 1992; they interpret their results as still supporting the original conclusion.
Both Levin and Lynn argue that data clearly support a hereditarian alternative: that the average IQ score and school performance of each group reflect their African descent. For all sizes, children with two black parents score lower than children with one black and white, who in turn score lower than children adopted with two white parents. Both ignore discussions about adopted Asians.
Waldman, Weinberg, and Scarr responded to Levin and Lynn. They note that data taken from the effects of adoption placement can explain observed differences; but they can not make that claim firmly because of pre-adoption factors confusing racial ancestors, preventing unambiguous interpretation of results. They also note that Asian data matching the hypothesis was temporarily omitted by Levin and Lynn. They argue that, "contrary to Levin and Lynn's statements, the results of the Transracial Minnesota Adoption Study provide little or no conclusive evidence for genetic influences underlying racial differences in intelligence and achievement," and note that "We think that is very unreasonable that these differences are entirely genetic or based on the total environment.the true cause of racial-group differences in IQ, or in other characteristics, tends to be too complicated to capture by placing them on a single dimension of heredeitarianism-environmentalism. "
In a 1998 article, Scarr wrote: "The black/black test performance adopted [in the study] is no different from ordinary black children who were raised by their own families in the same area of ​​the country. and I report the data as accurately and fully as possible, and then try to make the outcome fit for my comrades who are committed to the environment.In retrospect, this is a mistake. Transracial adoption study results can be used to support either a hypothesis of genetic differences or a one- because the children have a visible African ancestor.) We should be agnostic at the conclusion [...]. "The opinion then supports Scarr's reassessment. For example, one group of authors wrote, "In general, scholars in the field of intelligence see evidence from this study... consistent with environmental and genetic hypotheses for the causes of differences in Group IQ scores..."
Loehlin (2000) reiterates the puzzling problem of the study and notes that genetic and environmental interpretations are possible. He further offers another possible explanation of the result, namely a prenatal factor that is not the same: "[O] ne possibilities lie in the prenatal environment provided by biological mothers Black and White Black-Black groups, of course, all have mothers Black In White-Black Groups, almost all mothers born are white (66 out of 68) Willerman and his colleagues found that between the racial couples it made no difference whether his mother was black or white: The children obtained an IQ higher if she is white, they suspect that this difference is caused by the environment after childbirth, but can, of course, have occurred in prenatal pregnancies. "
The paper from Drew Thomas (2016), which re-analyzes these adoption studies found that once corrected for the attrition of low white IQ recipients, after being corrected for the Flynn effect because none of the Asian studies adopted had white, mixed and whites were adopted. the same score, the black participants scores slightly lower with the 2.5pt gap, which can be explained by their pre-adoption characteristics
See also
- Interracial adoption
- Twin studies
- Eyferth learn
- Heritability IQ
- Race and intelligence
References
- Jensen, A. R. (1998). Factor g. Westport, CT: Praeger.
- McCartney, Kathleen; Weinberg, Richard A., eds. (June 25, 2009). Experience and Development: A Festschrift in Honor of Sandra Wood Scarr . Sandra Scarr (epilogue). Press Psychology. ISBNÃ, 978-1-84872-847-9 . Retrieved December 20 2014 . Lay Summary - PsycCRITIQUES (December 20, 2014) title
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