nature vs nurture lec 3

Question 1

nature

Answer 1

genes

Question 2

what is a gene?

Answer 2

a gene is a physical and functional segment of deoxyribonucleic acid (DNA)

Question 3

what is the genome?

Answer 3

the whole sequence of an organism is called the ‘genome’ - instructions leading to basic body organs

Question 4

alleles

Answer 4

genes have different forms called alleles located at the same place (‘genetic locus’) on a chromosome. alleles have small differences in their DNA. each pair of alleles represents the genotype of a particular gene

Question 5

genotypes can be…

Answer 5

homozygous if there are two identical alleles at a particular locus and heterozygous if the two alleles differ. gene alleles can be dominant or recessive

Question 6

nature vs nurture

Answer 6

evidence that genetics determine certain physical traits is widely accepted but claims that physiological attributes are genetically predetermined are more controversial.

Question 7

alternative view

Answer 7

genes are probabilistic not deterministic. genes determine our biological blueprint. how that blueprint is expressed may be strongly influenced by the environment it exists in - our experiences - environmental external factors

Question 8

epigenetics

Answer 8

genes can be “turned on” or “turned off” depending on environmental experience. how DNA interacts with smaller molecules found in cells. how much or if certain genes are expressed.

Question 9

methyl groups

Answer 9

methyl groups - DNA “instructions” made from carbon and hydrogen bind to a gene (like a switch)

Question 10

histones

Answer 10

proteins - spools that DNA winds itself around. can change how tightly or loosely the DNA is wound around them. if the DNA wound around them is more loosely wound, the genes can be expressed more and if they are more tightly wound then they express less. every cell has a distinct methylation and histone pattern and that is what gives every cell orders

Question 11

caspi et al (2002)

Answer 11

explored the relationship between genes and environment (maltreatment) on behavioural development. longitudinal study of criminality in NZ studied 1000 people from birth to adulthood. retained 96% of the sample after 26 yrs. maltreatment during childhood increased the likelihood of becoming a violent offender, but did not guarantee it - bc of the interplay between genetic and environmental impacts. hypothesised that differences in the gene MAOA was associated with aggression. low MAOA activity in conjunction with maltreatment significantly increased the likelihood of negative outcomes

Question 12

behavioural genetics

Answer 12

studying twins enables us to document the relative influence of genes and environment on development. MZ twins = same pair of alleles. DZ twins = 50% shared alleles.

Question 13

the two designs often employed by twin studies

Answer 13

(1) keep genetic relatedness constant, while varying home environment - MZ twins in same households vs. MZ twins in separate households. (2) keep home environment constant, while varying genetic relatedness - MZ twins in same household vs. DZ twins also in same household

Question 14

minnesota twin project

Answer 14

researchers at the university of minnesota studied identical and fraternal twins over 20 years. over 100 sets of twins were reared apart. ppts completed comprehensive batteries of medical and psychological assessments.

Question 15

minnesota twin project findings

Answer 15

found that MZA twins are about as similar as MZT twins. approx 70% of variability in IQ can be attributed to genes. MZ twins reared apart are highly similar across many physical and psychological traits, despite contrasting environmental experiences. social economic status affects rate of cognitive development, but not final IQ.

Question 16

evaluating twin studies

Answer 16

identical twins spend more time together than fraternal twins - not always accounted for. may be that the prenatal environment has a crucial influence on children’s development. identical twins are more likely to have shared social groups than fraternal twins

Question 17

to what extent are we influenced by our peers? Judith Harris (1998)

Answer 17

peers have a greater influence than parents on a child’s development. alongside a child’s genes their peer group is the next most significant influence on their development. peer groups in middle-childhood and adolescence shape an individual’s personality in way that endure into adulthood. children and adults show context-specific beh - they can act differently depending on where they are or who they’re with. as children get older the “outside behavioural system” is more influential on their personality than their in-home behaviour.

Question 18

why are children influenced by their peers?

Answer 18

bc children identify with their peers, rather than adults, and therefore try to be successful within their peer group. peer groups develop their own culture, which can contrast with adult demand. within-group processes make children more similar (e.g. conformity) and more different (e.g hierarchies) to one another.

Question 19

evaluating peer group socialisation

Answer 19

difficult to test direction of effects (e.g genetically studious child is likely to join a studious peer group). parents can influence who a child is friends with. parents and peers may have influence in different contexts - behave differently in different contexts. the relative influences of parents and peers may be inter-dependent - if parents aren’t that supportive then your friends are more supportive and vice versa