More EEfRT Than It's Worth? Effort-Based Decision Making in Autism Spectrum Disorders

Background: The ability to choose an efficient goal-directed action involves careful consideration of the probability of obtaining a reward, the potential magnitude of the reward if obtained, and the effort expenditure required to complete the action. Clinical observations suggest that, in an unstructured environment, individuals with autism spectrum disorders (ASD) may make inefficient behavioral choices at the cost of other potential rewards (e.g., choosing to pursue unlikely friendships or spending an inordinate amount of effort obtaining circumscribed interests). Yet no behavioral study to date has assessed this ability in ASD.

Objectives: The current study aimed to examine effort-based decision-making processes in ASD and how these processes might be influenced by reward probability and magnitude. A secondary aim was to examine how patterns of decision-making might be related to the restricted interest and repetitive behavior domain of ASD [indexed by the Interview for Repetitive Behaviors (IRB) (Bodfish, 2003) and the Interests Scale (IS) (Bodfish, 2003)]. 

Methods: We compared the performances of adults with ASD (N=20) to IQ-matched control adults (N=38) on the Effort Expenditure for Reward Task (EEfRT) (Treadway et al., 2009). In this task, participants were provided with the probability of obtaining a reward and the possible reward magnitude. They were then asked to choose between an “easy task” (less motoric effort) for a small, stable reward or a “hard task” (greater motoric effort) for a variable but consistently larger reward.

Results:  A repeated measures ANOVA with the factors probability, magnitude, and group detected more hard task choices in the ASD group than the control group, F(1, 56)= 10.64, p= .002, and a significant probability x magnitude x group interaction F(4, 53)=4.12, p=.006, revealed that effort-based decision making in the ASD group was less influenced by reward probability and magnitude.  No differences were detected between groups in response latency, number of trials completed successfully, or the flexibility in changing responses from one trial to the next, p >.05. Across both groups, proportion of hard task choices was positively correlated with the Insistence on Sameness scale of the IRB, r(56)= .28, p= .04, and negatively correlated with the number of lifetime interests as indexed by the IS, r(54)= -.36, p= .009.

Conclusions: These results suggest that individuals with ASD may make less efficient behavioral choices and may expend undue effort to obtain rewards. It also suggests that individual differences in this tendency are related to greater rigidity and a narrower range of interests (i.e., more circumscribed interests). Although further research is warranted, these findings may ultimately shed light on the atypical response to social rewards and non-social rewards (such as circumscribed interests) in ASD and may have implications for ASD interventions that use rewards to motivate learning (e.g., ABA).