Hedonic Capacity Influences Motivated Behavior in Autism Spectrum Disorder
Objectives: Our research group recently reported different profiles of effort expenditure for rewards in adolescents with ASD (Mosner, Kinard, Mcweeny, Shah, Damiano, Burchinal…& Dichter, 2016). Specifically, adolescents with ASD were characterized by decreased motivated behavior in response to medium and small reward magnitudes and high reward probabilities on the Effort-Expenditure for Rewards Task (EEfRT). The goal of the current study was to explore whether depressive symptoms or hedonic capacity were related to patterns of motivated behavior in adolescents with ASD in this same sample.
Methods: Twenty-six typically developing controls (TDCs; age M= 15.81, SD=3.06; IQ M= 109, SD=10.82) and 49 high-functioning adolescents with ASD (age M=15.98, SD=2.59; IQ M=103, SD=17.00) completed the EEfRT. On each trial, participants choose between selecting an “easy task” for the chance to win a small, constant monetary reward, or a “hard task” for the chance to win a variable, but consistently larger monetary reward. Each choice was presented with a low, medium, or high probability of winning the reward if the task was successfully completed (Treadway, Buckholtz, Schwartzman, Lambert, & Zald, 2009). Depressive symptoms were measured using the Child Depression Inventory (CDI; ages 12-17; Helsel & Matson, 1984) and the Beck Depression Inventory (BDI; ages 18-20; Beck, Steer, Ball, & Ranieri, 1996). Because younger participants received the CDI and older participants received the BDI, CDI and BDI scores were standardized within groups and then combined to create a continuous measure of depressive symptoms examined across all participants. Hedonic capacity was measured using the anticipatory and consummatory subscales of the Temporal Experience of Pleasure Scale (TEPS; Gard, Gard, Kring, & John, 2006).
Results: Correlations between the CDI /BDI composite score and the anticipatory subscale of the TEPS and all EEfRT metrics were non-significant. There were significant correlations between the consummatory subscale of the TEPS and EEfRT choices on the high reward probability (r=0.37, p<0.05), medium reward magnitude (r=0.31, p<0.05), and low reward magnitude (r=0.34, p<0.05) conditions. These correlations remained significant when controlling for severity of ASD symptoms as measured by the Social Responsiveness Scale (SRS; Constantino et al., 2003).
Conclusions: These results extend prior findings on relations between hedonic capacity and effort expenditure for rewards in a nonclinical sample (Geaney, Treadway, & Smillie, 2015) to an ASD sample, although the prior nonclinical finding identified linkages with anticipatory pleasure (Geaney, Treadway, & Smillie, 2015) and the current ASD study found linkages with consummatory pleasure. These results suggest hedonic capacity is related to motivated behaviors in adolescents with ASD and that future studies addressing reward processing in ASD should consider hedonic capacity as an important explanatory variable.