Genetics (Mary and VonLyn)
To determine whether genetics or environment plays a bigger role in attitudes of people.

Target Population


- Participants

Adults in particular, but whole families were also examined

- Sample

Total of 26691 subjects, including 14761 adult twins and their parents, spouses, siblings, and adult children


1. Self-report questions about three sets of characteristics generally purported to have genetic components
2. Examine how well the characteristics correlated at a genetic level with all 30 attitude items listed


a. Family environments plays a greater role in attitude formation than in personality variables (personality has a stronger genetic component than attitudes)
b. Attitudes are partly, though indirectly, heritable, but attitudes with high heritability influence people’s actions more strongly than those with weaker genetic bases.
c. Genetic and biological factors lead to different experiences among individuals, which help create different attitudes

Ethics (did the research process raise any ethical issues?)

No ethical issues involved.

DeAngelis, T. (2004, April). Are beliefs Inherited?. Retrieved August 30, 2009, from APA Online Web site:
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Henry Chen and Tommy Fritz
Adoption Studies
Aim: To prove whether or not the connection between parental divorce and children's adjustment is genetically mediated
Target Population: Families
-Participants: Adoptive families that were recruited through two large adoption agencies in Colorado
-Sample: Adoptive parents were generally middle class and well educated. Adoptive mothers' average age was 33 years; adoptive fathers' average age was 34. The number of years of education was 14.7 for mothers and 15.7 for fathers. Over 95% of the adoptive parents were caucasian.
Procedure: At the age 12 assessment, probands and their families visited the lab for comprehensive assessment. Parents and probands were interviewed and asked to complete questionnaires and standardized tests. Teacher reports on behavioral questionnaires were collected by mail. In addition to this information, interviewers rated the proband's social behavior at the conclusion.
Findings: Research findings have been especially provocative in suggesting that significant variation in children's maladjustment in divorced families may be explained by long-standing family conflict, parental maladjustment, and the frequency of parents' relationship transitions. The current study sought to integrate the growing list of hypotheses explaining the association between parental divorce and children's adjustment with the increasing developmental emphasis on genetic factors in children's adjustment. In general, there were no huge differences between genetic families and adoptive families. Rather, adoptive families were less likely to divorce, though those that did were at around the same conditions.

O'Connor, T. G., DeFries, J.C., Caspi, A., & Plomin, R. (2000). Are Associations Between Parental Divorce and Children's Adjustment Genetically Mediated? An Adoption Study. Developmental Psychology, 36, RetrievedSeptember 2, 2009, from


Children's expressiveness linked to family and culture

Aim: To find out how “culture and family environment influence children's facial expressivity and create differences among children of the same ethnicity” (Munsey, 2006)

Target Population:
Participants: four groups of young Chinese and American girls
Sample: Chinese girls adopted by European-American families, mainland Chinese girls, Chinese-American girls and European-American girls who were not adopted

- Videotaped 3-year-old girls’ facial expressions as they watched mildly negative images, such as a puppy in a dirty cage, or happy ones, such as a bunny wearing Groucho Marx glasses
- “researchers also asked the children's mothers to rate their own emotional expressiveness, their parenting strictness and levels of aggravation they experience as a parent” (Munsey, 2006)

- European-American girls were more expressive then Chinese-American and mainland Chinese girls
- adopted Chinese girls were more expressive then Chinese-American and mainland Chinese girls
- “a mother's strictness, including her attitude toward the appropriateness of children's emotional expressiveness versus restraint, strongly predicted her daughter's expressiveness”
- family life is a stronger influence than ethnicity on a child's expressiveness
- cultural and family environment influence a child's expressiveness
- "There's a difference in expressivity between the different groups," says Camras, "but the mother's attitude is more of a factor." (Munsey, 2006)

Ethics: no ethical issues

Munsey, C. (2006, January 1). Children's expressiveness linked to family and culture. Monitor on Psychology, 37, Retrieved September 2, 2009, from