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Description: Human experiments have demonstrated that instrumental performance and causal beliefs of the effectiveness of an action in producing an outcome are correlated and driven by the probability of each action leading to a reward. The animal literature, however, shows that instrumental free-operant performance differs when outcome probabilities are matched while subjects undergo training under ratio or interval schedules of reward. In two experiments, we investigated whether humans causal beliefs would correlate with instrumental performance under interval and ratio schedules while matching outcome probabilities within subjects. We replicated the effect of reward schedule training on instrumental performance found in animals using two different types of interval schedules. However, we found that in both experiments causal beliefs were similar, and were higher when experienced outcome probabilities were increased in both schedules by experimental manipulations. These results suggest that instrumental performance and causal attribution in humans do not follow from the same psychological process under free-operant training.