In the t-test of calibration the results were statistically significant. The results supported this in that the contradicting instructions improved calibration significantly. The supporting reasons group showed relatively no change apparently because this is what people do naturally so there is no divergence from the normal way of concluding a problem. The group that listed both kinds of reasons unexpectedly showed very little improvement. A decrease in overconfidence achieved through examination of all the alternatives will increase calibration and the odds of being correct.
People have a tendency to produce supporting reasons when solving problems.
The both condition of the second experiment failed to improve calibration which does not support the hypothesis that increased effort will increase calibration. In several parts of the experiments the authors ignored the data of certain subjects and failed to use them in any way. In the first experiment time requirements were first implemented in the first half and only used in one question of the second half. In the first experiment apparently only a rather small portion of the subjects were used in each condition. If they really were all used the authors were very unclear as to why so little of the data were used.