Abstract: An experiment was conducted to investigate human causal judgments in the trial-by-trial presentation, and to test the associative theory, the power PC theory, the probabilistic contrast model, the weighted DP model, and the pCI rule. The participants were 65 college students. It was found that causal judgments had three characteristics: (a) Causal judgments were in accord with the weighted DP model in generative causes, (b) more causal judgments were in accord with the power PC theory in preventive causes, and (c) causal judgments were difficult to be described and generalized with a uniform pattern.

Key words: estimates of causal power, the power PC theory, the probabilistic contrast model, the weighted DP model, pCI rule, trial-by-trial presentation