Genes and behaviour

Question 1

genetics and behaviour debates

Answer 1

Free-will vs determinism
Reductionism vs holism

Question 2

genetic arguments of behaviours

Answer 2

• Based on the principle inheritance
  
  • Genes and their DNA passed down from parents to their offspring - 50% from each parent
  • Humans have 23 pairs of chromosomes - approx 20,000 - 25, 000 genes
  • Some genes identified for medical conditions
    E.g. Mutation in the BRCA1 and BRCA2

Question 3

gene

Answer 3

a unit or heredity, a region of DNA that encodes a specific trait or function

Question 4

genome

Answer 4

Refers to all the genes an individual possesses

Question 5

genotype

Answer 5

set of traits coded in individuals DNA

Question 6

phenotype

Answer 6

The characteristics manifested in an individuals appearance, characteristics or behaviour.
Can be observable (e.g. eye colour) or unobservable (eg: blood type)

Question 7

alleles

Answer 7

Different forms of the gene: can be dominate or recessive

Question 8

recessive alleles

Answer 8

Trait controlled by the recessive allele only develops if allele is present in BOTH chromosome pairs

Question 9

dominant allele

Answer 9

If trait is controlled by a dominant allele, only has to be present in ONE of the chromosomes in the pair

Question 10

behavioural genetics

Answer 10

Even if an individual has a genetic predisposition towards a certain behaviour, without the appropriate environmental stimuli, the gene is not “turned on” and the behaviour is not expressed

Question 11

diathesis-stress model

Answer 11

• a psychological theory that attempts to explain behaviour as a predispositional genetic vulnerability expressed as a result of stress from life experiences.
  predicts that an individual with certain genes, when exposed to a certain environment, is more likely to develop the condition that someone with the gene, but not exposed to the environment

Question 12

niche-picking

Answer 12

• way for genetic and environmental factors to dynamically interact
  genetic predisposition causes the individual to select certain aspects of the environment, which in turn can influence their behaviour

Question 13

epigenetics

Answer 13

the study of how your behaviours and environment can cause changes that affect the way your genes work

Question 14

MAOA gene

Answer 14

• aka the ‘warrior gene’
  
  • a gene carrying the aggression trait down to individuals
    signals from cells to produce MAOA enzyme

Question 15

MAOA enzyme

Answer 15

an enzyme that breaks down neurotransmitters in the synapse

Question 16

MAOA-L

Answer 16

• Low expression variant of gene
  Having this gene means less MAOA is produced

Question 17

concordance rate

Answer 17

• the correlation found between the heritability of a topic
• the higher the genetic relationship, the more similar the individuals will be if the characteristic being studied is inherited
  concordance rates will increase is heritability is high and vice versa

Question 18

twin studies

Answer 18

• MZ (monozygotic twins): genetically identical
  DZ (dizygotic) twins: no closer genetically than normal brothers/sisters

Question 19

family studies

Answer 19

• More representative sample of the general population
  
  • Ordinary brothers and sisters will share 50% of genes with each other
    Different degrees of genetical relatedness are compared with behaviour

Question 20

twin studies and concordance rates

Answer 20

Measure concordance rates of a particular trait across the two different types of twins (and maybe across other family relationships as well)

in context: refers to the chance that one twin will have a particular trait given that the other twin has it

Question 21

twin studies use

Answer 21

• Twin studies reveal the power of genes, but usually also hint at the role of the environment
  This means that even with sharing identical genes and being raised in similar environmental and social setting, there isn’t 100% change that one twin will develop a disorder even if the other has it.

Question 22

family/kinship/pedigree studies

Answer 22

• More representative sample of general population
  Child inherits half their genes from each parent
  
  • Shares 50% with sibling
  • Grandparents and grandchildren share 25%
  • First cousins share 12.5%
    In family studies, these different degrees of genetic relatedness are compared with respect to specific traits of behaviour

Question 23

genetic similarities

Answer 23

Greater the genetic similarity (relatedness), the greater the genetic influence

Question 24

strengths and weaknesses of twin studies

Answer 24

• Produced great deal of data in support of biological roots of disorders - has helped psychologists to stress prevention for those who are vulnerable to such disorders
  
  • High cross-cultural reliability of concordance levels
  • MZ twins are now rarely separated at birth and raised in a totally different environment, yet this is necessary to substantiate claims as it commonly occurred in the past
    MZ twins reared together share many of the same experiences. DZ twins reared together may not share the same experiences due to levels of attractiveness or temperament

Question 25

natural selection

Answer 25

• Survival of the fittest will pass on their genes to their next generation
  Adaptation- Disgust behaviour to avoid pathogens

Question 26

what is evolution

Answer 26

• Adapting to one’s surroundings
  
  • Best adapted = better chance of surviving
  • Strongest mate –> produce offspring who are stronger
  • Charles darwin

Question 27

theory of natural selection

Answer 27

• Species require adaptive characteristics to survive
  
  • Species who have characteristics better suited to the environment will be more likely to breed and pass on their traits
    Over generations the results of natural selection is that species develop characteristics that make it more competitive in its environment = adaptation

Question 28

mutations

Answer 28

• essential to evolution
  Every genetic feature in every organism was, initially the result of a mutation. The new genetic variant (allele) spreads via reproduction, and differential reproduction is a defining aspect of evolution

Question 29

differntial reproduction

Answer 29

comparing the successful reproduction rates of two groups of individuals in the same generation of a species population, each exhibiting a different genetically determined characteristic or genotype.

Question 30

useful adaptations

Answer 30

• Psychologists believe that if a behaviour exists today, then it must be a useful adaptation that has helped us survive and reproduce, a concept know in evolutionary theory as ‘survival of the fittest’
  
  • Point out that despite the wise diversity of human beings in different cultures scattered all over out planet, there are some reactions that seem to be almost universal - arguing that is because responses are adaptive
    ○ E.g:
    § Response of disgust to the smell of rotten eggs
    § Ideas of what is attractive in a mate
    Fear or dislike of spiders and snakes

Question 31

testability

Answer 31

lack of empirical evidence (you can’t “observe” anything evolutionary)

Question 32

falsifiability

Answer 32

the capacity for a theory to be proven wrong.

Question 33

speculations about the environment

Answer 33

• Evolutionary adaptation is always adaptation to a certain environment
  
  • To suggest evolutionary explanation of a trait, you need to have knowledge about the environment in which this trait evolved.
    However, our knowledge of the environments in which homo sapiens evolved as a species is scarce. A lot reasoning in this field, arguably, is speculative.

Question 34

retrograde amnesia

Answer 34

Describes amnesia where you can’t recall memories that were formed before the event that caused the amnesia
Usually affects recent memories, not ones from years ago

Question 35

anterograde amnesia

Answer 35

Condition where a person is unable to create new memories after an amnesia-inducing event
May involve partial or total inability to remember events that have happened

Question 36

declarative memory

Answer 36

The recollection of facts - whether as part of a specific event of just as unrelated information

Question 37

Episodic (declarative) memory

Answer 37

Memory involving connections to times of places (e.g. Birthdays)

Question 38

Semantic (declarative) memory

Answer 38

Simple facts that can be recalled but not linked to any specific episode of time (e.g. Capital cities, types of animals)