Lecture 2 Flashcards
What is the field behavioural genetics studying?
Discover the factors that are biological or environmental that contribute to our development.
What is epigenetics?
The environment can change our genes.
What is genotype?
Genotype is the set of genes you inherit from your parents at conception.
Define Phenotype
Is how your genes display themselves. Environmental factors such as malnutrition can affect phenotype.
Describe the results from the Rat Maze study of rats intelligence:
The bright rats offspring were brighter, but maze bright rats raised in an impoverished environment were just average, while maze dull rats raised in an enriched stimulus environment used all their potential and were also closer to average.
Describe polygenic behaviour:
Hundreds of different genes combining in different ways to create an effect ex. intelligence
What are three ways we can disengage the effects of genes and environment?
1) Adoption Studies
2) Family Studies
3) Twin Studies
How doe adoption studies work?
Study the similarity to adoptive (environment) vs biological relatives (genes).
What did the adoption study on extraversion find?
Children are more similar to biological parents in extraversion. It appears that genetics are playing a bigger role than environment.
What does a family study consist of?
Compare relatedness with concordance. If something has a strong genetic component it is e expected you will have more in common with a sibling
What are the types of twin studies?
Monozygotic vs Dizygotic
Reared together vs apart
What does it mean if twins reared apart have the same concordance rate?
environment doesn’t play a big role
What is the risk of developing schizophrenia for monozygotic twins if one has it?
50%
what is dizygotic twins risk of developing schizophrenia if one has it?
10%
What percent of MZ share placenta? DZ?
75% of MZ
1% of DZ
Therefore in the womb MZ have a more similar environment
What did the Minnesota Twin Study look at?
Twins reared apart and together (as control). It looked at differences in Height, weight, IQ and CPI personality
What did the Minnesota twin study find?
No significant difference for weight, height. IQ and CPI personality. As long as there is no extreme environment parents don’t affect kids.
Does environment actually matter?
It is possible that because of similar genes, MZ twin evoke similar effective psychological environment. ex. Athletic = team sports
Give an example of how genetics can change environment?
Kids who are naturally athletic will enjoy participating in sports and become more athletic :) or your own example
What is the Mozart effect?
University study in 90s where Undergrads who listened to Mozart before a test temporarily had increased scores.
What does science say Mozart and Baby Einstein do for your baby?
NOTHING Muwhaha
What is the fastest organ to reach adult size?
The brain
What percentage of the brain has grown by:
birth?
Two?
Six?
birth= 30% Two= 70% Six= 90%
When does the brain growth spurt occur?
Between birth and two
How many grams does the brain grow by between the age of birth and two?
1.7 grams/ day
What is myelination important for?
communication
What is one thing that can cause poor myelination?
malnutrition
How much of the brains volume is due to myelingation
50%
How do electrical pulses travel through the cell?
dendrites –> axon across myelin sheath to Synapse
What is synaptogenesis?
- Creation of new synapses
- Synapses are easily created and tons are created in the first year of life during the brain growth spurt
- Experiences and Environment is what causes synaptogenesis
- Neurons that encounter stimulus from our environment create synapses
When does synaptic pruning occur?
approx. 18 months
What happens if synaptic pruning doesn’t occur?
Children with autism have bad synaptic pruning
What structure of the brain is last to finish developing?
Cerebral cortex
What age does the frontal lobe keep developing to?
Age 20 and 30
How much of the brains volume does the cerebral cortex account for in adulthood?
80%
How are cortex growth spurts timed?
Timed to gaining certain abilities:
auditory visual - first year of life
Language - Preschool
Frontal - age 10-12
What are sensitive periods?
- A period during which a certain type of stimulation of the brain is necessary
- We believe the sensitive periods are when these areas of the brain are developing quickly
How do animal studies support sensitive periods? Nature needs nurture?
Kittens: brain damage and permanentlycan’t see if not exposed to light in 4th week of life.
Proof nature needs nurture:
Sensitive periods +
Rats: The brain size of rats in the impoverish envir. was smaller than rich envir.
What were the result of the East European adoption study?
Babies without stimulation adopted at:
0-6 mths= 1%more than brits cog. impaired
6-24 mths= (brain growth spurt) many impaired
after 2 yrs= Even bigger increase ( I don’t have % in my notes)
What are the two stages of brain development?
- Experience Expectant Growth
* Experience Dependent Growth
Experience expectant brain growth
- What the brain expects to get in order to develop
- Normal experiences, touching, feeling, moving, experimenting, cuddling, cooing
- this is all you need for optimal brain growth
- a finite amount that you need and exceeding that is not helpful
Experience dependent brain growth
Experiences because of your individual life and the things that you enjoy
- Study suggesting that the brains of poets and musicians are different because of the experiences/ expertise
- No limit, the more you do the more brain growth that occurs.
