Nature vs Nurture Flashcards
Nature definition
Innate factors: everything that happens before birth
Today, the meaning of nature means ‘genes’: hereditary material that is unchanging over the lifespan
Nurture definition
Things like parenting style, life experiences + other social phenomena
Also has broader meaning: everything that isn’t genes (environment)
Genes depend on the environment to have their effect
Example of interaction between genes + environment
PKU (phenylketonuria)
-Rare inherited disorder
-Learning disability caused by diet: reduced ability to metabolise phenylalanine, an amino acid
-Treated by avoiding foods that are sources of phenylalanine e.g. cheese, meats + seeds
-If the diet is strict, there are no symptoms of PKU at all
Genetically defined, but can be fully treated by diet
Example of interaction between genes + environment
Dyslexia
-Word reading significantly below that expected given a child’s age, intelligence and education
-Prevalence: 3-6%
-Described as having a genetic + biological basis (Fisher & DeFries, 2002)
Manifests itself differently across languages
-Transparent languages where word-sound correspondences are invariant (e.g. Italian): Fluency is affected
-Opaque languages with many to many word sound mappings (e.g. English): Accuracy + fluency are affected e.g. ‘rough’ ‘cough’ ‘through’ ‘thorough’ ‘bough’
The impact of dyslexia varies depending on the language
Dyslexia has a genetic basis but manifests differently across languages (environmental)
Example of interaction between genes + environment
Mouse-mothering
Weaver et al (2004)
-Two strains of mice
-One strain highly resilient to stress - all of this strain is genetically identical
-The other strain is very susceptible to stress - all of this strain is genetically identical
-Implant embryos of susceptible strain into a resilient mother mouse
-Resilient mothers lick + attend to their babies more than the susceptible strain would - mother treats them like their normal offspring
-The implanted susceptible strain grow up to be resilient - similar in resilience to mothers
Radically different behavioural outcomes for mice that are genetically identical but mothered differently
Genetic predispositions
Where an individual may not be born with something but may be at a high risk of acquiring it
-Autism, schizophrenia, ADHD, depression + bipolar disorder all have common genetic predispositions
-Certain genes which are also common in people with no disorder at all, are associated with slightly increased risk of all the above disorders
Risk: Probabilistic causes
Causes are only probabilistically related to effects
e.g. smoking + lung cancer
- Cases of lung cancer without smoking, or smokers living to old age do not undermine confidence in causal relation
-Like physical diseases, psychological disorders are caused by accumulation of many risk factors, each of small effect
-Individual causes may have risks for more than one disorder
What is meant by the environment?
Everything that isn’t genes
-Includes other things in the body such as stress hormones + vitamins
-May be things from outside world like pesticides + smoke
For psych it also means experiences
What are environmental modifiers?
Determine whether people with a genetic predisposition to a disease, disorder or positive outcome actually end up with the disease, disorder or positive outcome
-e.g. someone with a genetic predisposition to lung cancer may end up with lung cancer if they smoke
-e.g. someone may have a genetic predisposition to being very tall but would only end up tall with the environmental modifier of a balanced diet
How is the developmental phenomena explained?
Explained by an interaction between genes + environment
But things are more complicated - there are interactions of genes with other genes + multiple environmental factors. The nature of these interactions also changes over development
What are positive modifiers?
An environmental modifier changes the effect of a gene, also positively (e.g. vitamins protecting against a genetic predisposition to cancer)
-Even for genetically defined disorders, like down syndrome, which is associated with profound difficulty with spoken language, the environment can modify the consequences of any genetic effects
-Psychology-based interventions can improve behavioural, cognitive and academic outcomes
What are interventions?
Interventions are the way in which psychology is used to change the course of development
What is differential susceptibility?
Individuals vary in their sensitivity to their environmental influences, both positive + negative (Belsky, 1997)
-Belsky proposed that some people are more “plastic” or susceptible, meaning they are more affected by their environment (Belsky & Pluess, 2009)
e.g. Orchid vs Dandelion analogy
-Orchids: highly sensitive, flourish in supportive environments but struggle in adverse ones
-Dandelions: less sensitive, capable of adapting to a wider range of environments (Boyce & Ellis, 2005)
Differential susceptibility model
Interaction of environment quality + susceptibility
Pluess + Belsky (2009) research
Does children’s temperament moderate their response to different childcare environments?
-Interested in whether theres an interaction between children’s temperament + childcare environments
-Large, longitudinal sample involving children who were exposed to different types of childcare settings
Low-quality childcare: ‘Difficult’ children displayed more behaviour problems compared to those with low negative emotionality
High-quality childcare: ‘Difficult’ children showed fewer behaviour problems compared to children with low negative emotionality
Susceptibility makes people vulnerable to negative environments but also makes them more able to benefit from positive environments
