Lecture 2 - Love and prosocial behaviour 1

Question 1

What is genetic variation in vasopressin receptor gene AVPR1A associated with?

Answer 1

Pair-bonding behaviour in humans

Question 2

How did Bartels and Zeki (2003) use neuroimaging subtraction to find neural correlates of maternal and romantic love?

Answer 2

Neuroimaging subtraction technique:
Task activation pattern MINUS control pattern

Show person picture of another’s daughter or husband
This is control
Then show person picture of their daughter or husband
This is task activation
Can see which areas specifically are active due to maternal and romantic love

Question 3

What did Bartels and Zeki (2003) find about neural correlates of maternal and romantic love?

Answer 3

Specific regions for each kind of love, as well as overlapping areas in the brain’s reward system that coincide with areas rich in oxytocin and vasopressin receptors

Question 4

Is the prairie vole monogamous?

Answer 4

Yes
A male and female typically form a life-long pair bond after one mating/ cohabitation episode
Rare to be a monogamous mammal

Question 5

What is the evolutionary reason behind biparental care in humans?

Answer 5

If you wanted to make a species evolve whose brain was so complicated and capable of such intelligence and adaptability that it takes an individual c.13 years to become fairly independent, and c.20 years to fully mature
Imagine the resources and time that would need to be devoted to the young of such a species!
Male and female team up as economic unit - makes sense as individual humans require lots of investing and resources

Question 7

What does a monogamous social structure entail?

Answer 7

Lasting pair bond between adult mates
Both male and female care for offspring

Question 8

What type of chemical are oxytocin and vasopressin?

Answer 8

Prosocial neuropeptides

Question 9

Generally, are oxytocin and vasopressin more important in males or females?

Answer 9

Oxytocin more important in females ♀
Vasopressin more important in males ♂

Question 10

What brain regions have higher oxytocin receptor density in the prairie vole compared to non-monogamous rat and mouse?

Answer 10

Nucelus accumbens, caudate, putamen

Question 11

What is the method of staining for areas with more oxytocin/vasopressin receptors?

Answer 11

Inject radioactive substance that binds to vasopressin/oxytocin receptors
After animal killed and dissected, more of the substance indicates more receptors as more has bound

Question 12

What brain regions have higher oxytocin receptor density in the prairie vole compared to non-monogamous montane vole?

Answer 12

PFC = prefrontal cortex
CP = caudate and putamen
NAcc = Nucleus Accumbens

Question 13

How was the role of oxytocin investigated using blocking?

Answer 13

By blocking oxytocin receptor activity in the receiving neurons in oxytocin-receptor-rich brain regions
Inject something that binds to receptors but does not function as oxytocin

Question 14

What was the method of the partner preference test by Ross and Young (2009)?

Answer 14

Cohabitation period - Bring together a male and female vole together for a fixed cohabitation period (c. 18-24 hours.) Observe. They may mate (check for mating.) Subject may be male or female. Partner and stranger = opposite sex.
Typically female in oxytocin studies, male in vasopressin studies

Test period - Then observe interactions over a test period (e.g. 3 hours)
Compare vole they cohabitated with and the new vole they did not know
Ask eg. How much time do these sexual partners spend side-by-side? Then compare to ‘stranger’ vole who has not mated with subject.
Observations should be scored blind to experimental group

Question 15

What did Ross and Young (2009) find about oxytocin in their partner preference test?

Answer 15

Control - cerebrospinal fluid - unaffected (more time with partner than stranger)
Oxytocin antagonist - prevents oxytocin from bonding - in these areas:
Nucleus accumbens and PFC - affected (more time with stranger than partner) key areas for oxytocin influencing pair bonding
Caudate and putamen - part of basal ganglia - reward system - unaffected (more time with partner than stranger)

Key areas - nucelus accumbens or PFC

Question 16

When do oxytocin and vasopressin peak in human males during sexual activity?

Answer 16

Vasopressin - during arousal
Oxytocin - during orgasm

Question 17

What are the differential roles of oxytocin and vasopressin in human males?

Answer 17

Vasopressin - wanting? seeking?
Appetitive?
Like Dopaminergic
Signal in nucleus accumbens

Oxytocin - liking?
More towards ‘satisfaction’
More like Opioidergic signal

Question 18

What does the opiod-antagonist naloxone do to females after sexual activity?

Answer 18

Blocks release of oxytocin after orgasm - less pair bonding

Question 19

How do the two neuropeptides oxytocin and vasopressin interact with the reward system?

Answer 19

Produce attachment towards person with whom you feel nice/orgasm with

Question 20

What was the result of manipulating the gene expression of V1aR gene in the solitary meadow vole? (Lim et al, 2004)

Answer 20

They showed much increased partner preference

Question 21

How was the V1aR gene overexpressed in Lim et al (2004)?

Answer 21

Part of the gene in a prairie vole was inserted into the meadow vole brain (ventral pallidum) using a viral vector

Question 22

What was the result of Lim et al (2004) changing gene expression of V1aR gene in meadow voles?

Answer 22

Meadow voles who are usually promiscuous showed significantly increased huddling with partner behaviour compared to control gene and same gene injected into different areas (i.e. not ventral pallidum)

Question 23

What does overexpression of V1aR gene lead to? (Lim et al, 2004)

Answer 23

Increases number of Vasopressin 1A receptors (proteins) on the post-synaptic membranes of vasopressin-responsive neurons (in that brain region). The same amount of vasopressin released would now have a much larger effect on the vasopressin-responsive neurons.

Question 24

What behaviour does increased V1aR receptor density result in?

Answer 24

Adult pair bonding (at least for males)
Cuddly monogamy

Question 25

Does variation in receptor activity (oxytocin and vasopressin) control strength of pair bonding?

Answer 25

Neural manipulation experiments suggest yes: Blocking these receptors eliminates post-coital huddling Increased receptor density increases post-coital huddling

Question 26

What is an issue with experiments examining species differences or experimentally-induced (exogenous) differences?

Answer 26

Does not examine individual differences in humans - cannot say the same thing happens in humans

Question 27

Can oxytocin and vasopressin levels be studied using causal manipulations causing exogenous variation in humans?

Answer 27

No - this would be unethical Instead, we can observe endogenous (naturally occurring) variation

Question 28

Is this the same gene? V1aR gene, AVPR1A, vasopressin receptor 1A gene

Answer 28

Yes

Question 29

What did Walum et al's Partner Bonding scale comprise of questions from?

Answer 29

Consisting of 13 items overall: Dyadic adjustment scale (DAS) (7 items) (getting along, doing things together) Support Seeking and Giving (SSG) assessment (5 items) (positive social engagement) Marital instability scale (MIS) (1 item) (Serious Marital Threat question Has subject experienced marital crisis or threat of divorce during the last year? From a Life Events questionnaire) Also - marital status - married or cohabiting?

Question 30

What is a limitation of the sample used in Walum's study of AVPR1 and marriage satisfaction?

Answer 30

All couples were together for 5 years - does not include people whose expression of the gene makes them not want to be in a long-term relationship at all However, this may explain small effect sizes - the present study may underestimate the way in which the 334 allele predisposes against ‘marriage’

Question 31

What were the conditions for men's genetics in Wallum's study of AVPR1?

Answer 31

0 copies of risk allele, 1 copy or two copies Allele - more likely to have worse marriage

Question 32

What were results of Walum's study of AVPR1 and marriage satisfaction?

Answer 32

If you are a male ♂ with one or two copies of the risk allele: You are less likely to get married (an objective fact) You are more likely to experience a serious threat to your relationship (your self-report) You show a less-bonded pattern of relationship with your partner (your self-report) Your female partner reports less quality in the relationship Particularly regarding affection Finally, no significant effects for female polymorphisms of the AVPR1a gene Shows vasopressin more relevant for males than females

Question 33

How did positive and negative conflict behaviour vary in men and women when resolving an artificial conflict after being given intra-nasal oxytocin spray? Ditzen et al (2009)

Answer 33

Oxytocin - more positive behaviour Placebo - more negative behaviour Men show higher pos and neg levels - women do not vary as much

Question 34

Does oxytocin reduce stress?

Answer 34

Yes Subjects given oxytocin show lower cortisol levels after couple conflict Shows exogenous variation

Question 35

How did Gonzanga et al (2006) test for romantic display associated with oxytocin release?

Answer 35

25 young women recount and relive a positive emotion regarding love or infatuation with their male partners present (typically 2 minutes long) Blood drawn from subjects during this and earlier baseline condition, later tested for oxytocin content Scorers observe non-verbal behaviour in women: Affiliative (romantic), e.g. affirmative head nods, Duchenne smiles (genuine smile), leaning towards partner Sexual, e.g. lip licking, lip puckering, tongue protrusions

Question 36

Does romantic display correlate positively with oxytocin release? (Gonzanga et al., 2006)

Answer 36

Yes Duration of romantic displays as % of duration of romantic episode narration… (~ 2 minutes) correlated positively with increase in oxytocin relative to first baseline

Question 37

Does oxytocin correlate with overt sexual displays? (Gonzanga et al., 2006)

Answer 37

No correlation of oxytocin with overt sexual displays Maybe not appropriate index of sexual behaviour

Question 38

What is the strategy mediated by oxytocin and vasopressin compared to that of testosterone?

Answer 38

Strategy mediated by Oxytocin & Vasopressin ‘Quality of bond not quantity’ Commitment to existing bonds i.e. enhancement of adult pair bond i.e. enhancement of parenting Reduced aggression with mate & progeny - Co-operative - brings benefits of monogamy - promotes love Strategy mediated by Testosterone ‘Quantity of mates not quality’ Focus upon more partners More attractive partner? i.e. more ‘mating’, less ‘pair bonding’ i.e. more children Higher aggression with mate & progeny? - Competitive - brings benefits of polygamy (infidelity) - promotes sex

Question 39

Why are there two strategies for reproduction? - quantity and quality (mediated by different chemicals)

Answer 39

Pure strategy of either not that evolutionarily stable? - If everyone is ‘high TEST’ only, children die at too high rates, or do not thrive, from abandonment & low parental investment. Influx of ‘high OXT/VASP’ will spread because children suddenly thrive to adulthood, and then produce children themselves. - If everyone is ‘high OXT/VASP’ only, network is highly vulnerable to influx of ‘high TEST’ strategy. A bit like loafers. So humans exhibit a mixture of both strategies, and individual differences.

Question 40

What happens to testosterone during ageing?

Answer 40

It reduces

Question 41

Are men producing more testosterone less likely to marry? (Booth and Dabbs)

Answer 41

Yes, and more likely to divorce

Question 42

Are men with higher testosterone more likely to leave home because of troubled marital relations, have extramarital sex, physically abuse spouse and have lower quality of marital interaction?

Answer 42

Yes

Question 43

What is a strength of (Booth and Dabbs)? (Testosterone and marriage)

Answer 43

Adjustment for age Many different facets of this form of adult pair bonding (marriage)

Question 44

What is the likelihood of hi-test compared to low-test men to not get married, to divorce/seperate, to be unfaithful and to be abusive

Answer 44

Hi-test men > doubly likely to not get married Hi-test men > nearly doubly likely to divorce/separate Hi-test men > nearly doubly likely to be unfaithful Effect not as clear for abusive behaviour - other factors at play

Question 45

According to Mascaro, Hackett and Rilling (and others), the biology of human males represents a trade-off between what two things?

Answer 45

a) effort spent on mating & b) effort spent on parenting

Question 46

Chin et al studied homosexual women couples' testosterone levels, pair bonding and parenting - what did results indicate?

Answer 46

These Negative correlations were reported: 1) Birth mothers reported HIGHER relationship satisfaction when their partners had LOWER testosterone (TEST) 2) Non-birth mothers reported higher perceived support and relationship commitment when their partners had LOWER TEST 3) Non-birth mothers with LOWER TEST reported receiving MORE support, and HIGHER relationship satisfaction, commitment & investment

Question 47

Are testosterone level heritable?

Answer 47

Yes

Question 48

What are the testosterone level correlations between dutch adolescent twins?

Answer 48

Correlations in MZ > correlations in DZ twins Identical twin values (MZ) are very similar (in both males & females) and higher than for non-identical twins: males: 0.66 > 0.34 females: 0.60 > -0.01

Question 49

What is the relationship between fatherhood and marriage, and testosterone?

Answer 49

Seems likely that the experience of marriage and fatherhood lower testosterone, as well as that low testosterone predisposes to less marriage and fatherhood

Question 50

What effect does child maltreatment have on adult oxytocin levels?

Answer 50

Maltreatment = drop in oxytocin

Question 51

What is a reason for lower oxytocin levels in adults who have experienced child maltreatment?

Answer 51

1) Low-loving interactions (hugs/cuddles/praise) gradually reduce OXT 2) Protective mechanism – ‘shutting down’ normal levels of prosocial responsiveness because these would lead to more stress/pain (avoid getting hurt)

Question 52

What do the GG/GA alleles of the rs53576 SNP of the Oxytocin Receptor typically confer?

Answer 52

Increased empathy and trust

Question 53

What effect does child maltreatment have on depression? (costs of being prosocial in a low-loving adverse world)

Answer 53

Depends on allele of oxytocin receptor? Under high levels of childhood maltreatment, this prosocial predisposition becomes maladaptive. Overly loving, trusting, giving to e.g. callous, psychopathic parents is not good for you. - Prosocial individuals more likely to get depression