Miss Alida M Acosta Ortiz

Background: Behavioural economics offers experimental paradigms to shed light on the complexities of social decision making. In the Ultimatum Game (UG; Fehr & Schmidt, 2006), for example, participants are asked to share a given amount of money (£10) with another person in whatever proportions they wish. If the second person accepts the offer, money is paid out accordingly but if she rejects, neither player receives anything. Rationally players should offer as little as possible because other players should rationally accept any offer greater than 0. However, most people tend to offer equal shares and tend to reject offers of less than 30% of the total. Since many social-emotional (e.g, empathy) and social-cognitive (e.g., Theory of Mind) processes are at play in these scenarios (Takagishi, 2009; Sanfey 2007), one would expect individuals with ASD to behave differently in the UG. A study by Sally & Hill (2006) is the only one addressing this question to date and suggests that ASD children tend more to accept unfair offers in the UG, although this was unrelated to their ToM

Objectives:

• To identify whether there is a difference between ASD and TD adults in the rate of acceptance/rejection of an unfair offer (£3-£7) in the Ultimatum Game.

• To examine the link between an individual’s decisions during the UG and their ToM, empathising and systemising skills; their propensity to adhere to principled moral rules, and their tendency to avoid punishment and/or seek rewards.

Methods:  40 ASD and 32 TD adults, matched on age and IQ, participated in a real-life one-shot UG. They were asked to decide whether to accept or reject an offer of £3 out of £10. Participants also completed some cognitive tasks including the Reading the mind in the eyes test (Baron-Cohen et al 2001), the empathising and systemising questionnaires (Baron-Cohen, 2009), the behavioural inhibition/activation scales (Carver & White, 1994) and an ethics position questionnaire (EPQ; Forsyth, 1980).

Results:

Overall, our results indicated no group difference in the proportion of participants who rejected the unfair offer (ASD = 47%; TD = 45%). As expected, ASD participants scored lower on ToM and empathising and had significantly higher scores on the behavioural inhibition scale, suggesting that they might be more sensitive to losses. No group differences were observed on systemising, the BAS scale or the EPQ. 2x2 ANOVAs of the various dependant measures showed that in both groups those who accepted unfair offers score higher in ToM and lower in BIS. Interestingly, the only group difference emerged in relation to the EPQ where only ASDs who rejected unfair offers scored higher than those who accepted.

 Conclusions:  The current data do not suggest that ASDs respond differently to ‘fairness’ than TD participants in the Ultimatum Game. ToM abilities and sensitivity to losses appeared to motivate decisions to reject unfair offers to similar extents in both groups. Interestingly, however, results from the EPQ suggest that ASDs may be more reliant on a moral heuristic than TD individuals in reaching their decisions