Affective State and Decision Making in Autism Spectrum Disorder: Evidence from the Ultimatum Game
Classical economic models regards decision-making as an exclusively cognitive process, however Bechara et al., (1997) and Camerer (2003) show that emotions and their associated physiological process influence decision making. This was demonstrated by Sanfey et al., (2003) and Van’t Wout et al., (2006), in the context of the Ultimatum game (UG; Güth et al, 1982), in which a proposer can decide how to split a given amount of money (£10) between themselves and a responder who can either accept or reject the offered amount. If s/he accepts, the money is paid out as proposed; if s/he rejects neither participant receives any amount. Both Sanfey et al., (2003) and Van’t Wout et al., (2006) reported an association between high skin conductance and rejection of unfair offers, suggesting that emotional processes influence people’s decisions. Social-cognitive processes are also thought to play a role, such as considerations of fairness and the intentions of proposers. The difficulties ASD demonstrate in social cognition and in processing emotional related information (Johnson et al, 2006; Maras, Gaigg, & Bowler, 2012) would lead to the prediction that the decisions ASD make in the UG would be less contingent on emotional responses to offers and be less influenced by whether offers stem from an intentional agent (human) or non-intentional machine (computer).
Objectives: To test the above prediction by examining the physiological responses to human vs. computer generated offers in ASD and comparison participants on a multitrial version of the UG that require a standard accept/reject response to offers that varied in fairness.
Methods: 36 ASD and 36 age and ability matched comparison adults completed 24 UG, half time receiving offers from people and the other half pseudo-randomly generated by a PC. In each condition, twelve trials were fair (£5 vs £5) and twelve unfair (£9 vs £1; £8 vs £2; £7 vs £3). Offers were presented in a random order and skin conductance and heart rate recorded. After offer presentation, in the form of a short video-clip or animation, which showed either a real person or the computer generating an offer, participants were prompted to accept or reject. Not time limit was imposed and feedback was given at the end, yet participants knew that all decisions would be paid out at 10% of their value at the end of the experiment
Results: Unfair offers proposed by humans were more frequently rejected than unfair offers proposed by the computers. Similarly, GSR responses to unfair compared to fair offers were greater in the human than the computer condition F (1,65) = 5.911, p = .018, η2 = .083 .No differences between ASD and comparison participants was observed
Conclusions: The results confirmed observations by Sanfey et al., (2003) and van’t Wout et al., (2006), which show that emotional and social-cognitive factors are involved in rejection of unfair offers in the UG. The predicted difference for the ASD was not supported, suggesting that difficulties in emotional and social-cognition might not confer a disadvantage in the context of social-economic decision making.