Interpersonal Decisions Flashcards
Explain Ultimatum game?
Responder and proposer. Pot of money. PRoposer makes offer.
Responder accepts split = both keep share of money agreed
Rejects = neither get any.
One shot game
What finding is common in ultiamtum game?
Many reject low offers = widely replicated
Resitant to many permutations of game.
‘Irrational’ rejection
What factors could affect interpersonal decision in economic situations?
Dominance, reputation building
Pro-socialising – fariness, altruism, social norms
Motivation to maximise monetary gain
Who did an expeirment into hertitability of ultimatum game offers?
Wallace et al, 2007 – same sex twins in Sweden. Ultimatum game = written down offers
Genes contribute to 42% variance in responder beahviour
No sex differences
Who did an expeirment into natural testosterone levles and ultimatum game?
Burnham, 2007 – high T men reject low ultimatum game offers. Those who reject $5 from $40 = sig higher test levels than those who accept
HIgh T men = more likely to see low offer as challenge - ‘reputation management’
Who did an experiment into ultimatum game whilst manipulatin testosterone levels?
Zak et al, 2009 – increasd T levels by spreading Androgel/control gel on shoulders and upper back
T increases minimum acceptance offer
Who did an experiment in to heritability of testosterone levels - what were teh results?
Harris et al, 1998 – MZ twins = much more similar than DZ twisn.
Males – 0.66 - 0.34
Females – 0.60 - 0.01
Father son correlation = low - maybe differen genes for differnet age groups?
What is the dictator game?
Dictator decides how much to keep and how much to give you
What did Knafo et al, 2008 do?
Looked at region of DNA that regulates experssion of the vasopression 1a receptor. RS3 length = positively associated with higher levels of hippocampal messenger RNA for the vasopressin 1a receptor
i.e. it is v probable that RS3 length determines V1s receptor density.
Longer RS3 promoter region = more vasopressin receptors
What conclusions did Knafo et al, 2008 draw?
LArger the stretch of DNA in someone the more money they deicde to give to other people
Ind diffs in thsi game = at least partially determined by genetic differences relating to vasopressing signalling
Who did an experiemnt with rs1042778 polymorphism?
Israel et al, 2009 – this polymorphism in gene coding for oxytocin receptor = associated with less generous splits to recipient in dictator game
What is the system that ocntrols motivation for monetary gain?
BAS
Who did an experiment on both games and BIS/BAS scores?
Scheres & Sanfey, 2006
HIgher scores on BIS/BAS Qs:
- make higher offer to responders in ultiamatum game (bit weak)
Give less money to recipients in dictator game
Maximise the difference bteween their ultimatum game offer and their dictator game allocation
How did Scheres & Sanfey, 2006 interpret their results?
People with higher BIS/BAS drive seek to maximse likelihood of reward and maximise amount of reward
BAS levels determines strategy (‘UG offer- minus - DG offer reflects ‘strategic thinking’
Who disrupted the PFC and how?
Knoch et al, 2006 – TMS.
