TAYLOR BUSER AND CINDY UNG

Differential Parental Investment in Families with Both Adopted

and Genetic Children

Introduction: Background

Hamilton (1963): Kin selection theory means altruism correlates with shared genes

Daly & Wilson (1980): Stepchildren threaten resources of genetic children to stepparent

Daly & Wilson (1985, 2001): Children with stepparents are more likely to be abused

Introduction: Background

Daly & Wilson (1980): Adoption occurs between kin, fitness benefits outweigh cost

Callan (1985): In the West, adoption brings adaptive social benefits Childless: “materialistic, selfish” With children: “loving, hardworking”

Contrary evidence Hamilton et al. (2007): Adoptive households give

more investment than genetic households

Introduction: Hypothesis

Limitations of background research Between vs. within

Given that no genes are shared with household members No selective drive to invest Higher probability of negative outcomes

Hypothesis: parents of at least one adopted and one genetic child bias investment toward genetic offspring

Methods – Participant Selection

Adoption agency in MidwestRandomly chosen families with at least one

genetic and one adopted child over 22 years old at time of study

Sample sizes vary because some families had children younger than 22

Methods - Survey

Children referred to by birth or adoption order

Asked which investments were given and how much time was invested in each child

Asked about outcomes of each child in four categories: Health, Education, Personal, and Time

Methods – Statistical Methods

SPSS Controls for investment were combinations

of: age, birthorder, gender, education, marital status, and parents’ income

Sample sizes vary because investments did not apply to all children

Results – Adoptive Parents

126/3oo surveys returned75.6% of respondents were womenAverage age: 57.6 Average spouse age: 57.33Median income: $50,000 to $74,9995.9% divorced57.6% adopting because unable to

biologically conceive children

Results – Adopted and Biological Children

Average age: 26.950.3% Male45.2% AdoptedAdopted and genetic children didn’t differ in birthorder

or gender Incomes did not differ when controlled for several factors

Results: Comparisons in investment

Results: Comparisons in investment

Differential investment in education Preschool, tutoring, summer school

Personal investments Cars, rent, personal loans

Cultural activities Sports?

Promote intrinsic motivation Find new skills

Outcomes of adopted and genetic children

Discussion

Hypothesis is not supported, investment was not biased towards genetic children

Positive investments associated with negative outcomes

Most adoptees did not need any treatment or extra investment from parents

Other research shows that adoptees are prone to other difficulties as well

Discussion: The “Squeaky Wheel”

Summer school and private tutoring can be remedial Same can be said for rent, treatment, public

assistance Parents don’t invest more in adoptees

because they are favored, but because they need more help

Discussion: Adoptees genetically predisposed?

Adoptees could be genetically predisposed to negative outcomes at higher rates

Alcohol and drug addiction, mental disorders are influenced by genetic factors As are nonviolent criminality, educational performance

Birthmother information rare because of confidentiality issues One study: mothers gave up their children for adoption

because of personal difficulties Another study: birth parents gave their children up

because of substance abuse, physical abuse, and mental illness

Discussion: Why adopt?

Our psychology is product of strategies that paid off in the past

Other cultures need optimal family size, not usual for U.S. families

Adaptive: Social acceptance, “the American ideal”

Maladaptive: Instinct fulfillment Industry of child adoption very new Takes time for a mechanism to be extinguished,

maladaptive or not

Discussion: Limitations and beyoooond

Limitations: Systematic ascertainment bias Parents want to prove they don’t favor genetic

children Age children were adopted, where they were adopted

fromFurther research:

Foster homes: If “the squeaky wheel gets the grease”, foster homes = more investment

Genetic similarity and prejudice: one white / one foreign adopted children, which one is favored?