BACKGROUND: Effort can take a variety of forms including physical (e.g., button pressing) and cognitive (e.g., working memory tasks). Few studies have examined whether individual differences in willingness to expend effort are similar or different across modalities.
METHODS: We recruited 30 individuals with schizophrenia and 44 healthy control subjects to complete 2 effort-cost decision-making tasks: the Effort Expenditure for Rewards Task (physical effort) and the cognitive effort discounting task (cognitive effort).
RESULTS: Willingness to expend cognitive and physical effort was positively associated for both individuals with schizophrenia and control subjects. Further, we found that individual differences in motivation and pleasure dimension of negative symptoms modulated the association between physical and cognitive effort. Specifically, participants with lower motivation and pleasure scores, irrespective of group status, showed stronger associations between task measures of cognitive and physical effort-cost decision making.
CONCLUSIONS: These results suggest a generalized deficit across effort modalities in individuals with schizophrenia. Further, reductions in motivation and pleasure may impact effort-cost decision making in a domain-general manner.
