1. The Surprisingly Small Influence of Family

2. Thesis Families (parents and siblings) have a surprisingly small influence on children’s psychological development Three examples: – Cognitive development – Language development – Personality development

3. Evidence of Effectiveness The fact that children improve on a task after instruction is not evidence that the instruction was effective Example: You can instruct a child in how to walk, but children learn to walk at the same rate without any instruction

4. Basic Cognitive Skills Infants develop depth perception without instruction, and almost always around the same time period (when they first start to crawl) Consistent with development of depth perception being genetically determined

5. Piaget’s Theory of Cognitive Development Order in which cognitive abilities are acquired is consistent, even though exact ages vary across individuals – Object permanence – Conservation

6. Language Development Children in any normal language environment (and sometimes without one) learn spoken language without instruction Children are remarkably resistant to correction in their language use

7. Language Development Similar sequence of development across languages (even for acquisition of sign language) Examples: – Babbling at about 6 months – First words around 1 year – Use of grammar around 2 years – Overregularization of grammatical rules

8. Personality Development Genetic component predicts behavior across situations Environmental component predicts behavior in specific situations

9. The Case of Birth Order Small or non-existent differences in personality traits between different birth orders Birth order effects are context-specific; they predict behavior within the family but not in other situations

10. A Few Cautions Parents DO matter in many areas In highly abusive or neglectful situations, children do not develop normally Parents should treat their children well even if they do not have much impact on psychological development; it is still important to treat people well