Download Genetic and Environmental Influences on Development

• Some developmental researchers argue that:
– Correlations between parenting behavior and
children’s behavior mainly reflect
• Direct transmission of genes from parent to child
(passive g-e correlations)
• Effects of children’s genes on parenting behavior
(evocative g-e correlations)
– Some researchers (e.g., Rowe, 1994; Scarr,
1992) argue that the presence of these g-e
correlations indicates that genetic differences
(rather than parenting or other environmental
influences) are the main influence on children’s
behavior and characteristics
Challenges
1. Maccoby (2000) argues that assuming evocative g-e
correlations reflect genetic influence
underestimates parenting effects
– Ignores bidirectional influences between parent and child
•
Children do elicit/evoke different responses from parents based
on genetic differences
•
But parents’ responses are also likely to change child behavior
2. Additive model of genetic and
environmental influence is not valid
– G + E = 100% of variation
– Assumes that genes and environment are
independent
– G-E correlations (and G-E interactions) do not
“fit” in an additive model
3. In research that accounts for g-e
correlations, there are still independent
effects of parenting
• O’ Connor, Deater-Deckard, Fulker, Rutter, &
Plomin (1998)
– Examined relations between “coercive” parenting
and antisocial behavior in late childhood/early
adolescence
– Longitudinal adoption design using data from the
Colorado Adoption Project
• Adopted children were classified as being at genetic
risk (n = 38) or not (n = 50) for antisocial behavior
– Based on biological mothers’ self-report of their own
antisocial behavior (collected prior to birth of child)
• Adoptive parents reported on their own parenting
beginning children were 7 and continuing through
age 12
– Negative control, inconsistent parenting, positive
parenting
Findings:
• Children at genetic risk were more likely to receive
negative parenting from adoptive parents than
children not at risk
– Indicates an evocative gene-environment correlation
• Association between negative parenting and
children’s antisocial behavior
– Most of this association was not explained by the g-e
correlation
– Suggests an independent effect of parenting on children’s
behavior
Gene-Environment Interactions
• An interaction is indicated if:
– The same environment has different effects on
two organisms, depending on the organisms’
genes
– Organisms with a given set of genetic traits react
in one way under one set of environmental
conditions but another way under different
environmental conditions
• G-E interactions do not “fit” an additive model
• Studies indicate interactions between child
temperament and parenting behavior
• Bates, Pettit, Dodge, & Ridge (1998)
• Examined relations between “restrictive
parenting” and temperament dimension of
“resistance to control”
– “Resistance to control” = child’s failure to comply
with parental attempts to stop or to redirect the
child’s action
– “Restrictive Parenting” = Efforts such as
prohibitions, warnings, and scoldings to manage
inconvenient or potentially harmful child actions
• Examined these variables in relation to
externalizing behavior problems at ages 7 to
11 years
• Findings indicated an interaction between
restrictive parenting and temperamental
resistance to control
– Resistance to control was more strongly related to
externalizing behaviors when mothers were low in
restrictive parenting
• Studies in the field of molecular genetics also
indicate gene-environment interactions
– Mostly animal research to date
– Very promising avenue for identifying and
understanding g-e interactions in human
development
Suomi and colleagues
• Have identified an allele of a gene that is associated with
a “reactive” (fearful) temperament in Rhesus monkeys
• Monkeys carrying the reactive allele are more vulnerable
to early maternal deprivation than monkeys without the
allele
– Less socially competent and less competent in mothering their
own offspring
• Also evidence that “cross-fostering” newborn reactive
monkeys to non-reactive mothers buffers them from
developing strongly reactive behavior