McGwire insisted the performance-enhancing drugs he used did not actually enhance his performance. The dosages were too low and his physical ability too divine, turns out, for the drugs to have an impact on his body, particularly as it related to his hitting. “I was given the gift,” he told Costas, “to hit home runs.” He said he would have hit every single one of them had he never injected a drop of anything. “Absolutely,” he said. “I truly believe so.”Some sportscasters are calling him out for lying in order to boost his chances of getting into the HOF, or something. I do not believe that he is consciously lying, in part because I have read about how powerful the self-serving bias can be. For example, children given methylphenidate attribute their success on impulsivity tests to effort and ability much more so than to medication, even when a double blind design ensures that in fact the medication leads to significantly fewer errors than placebo.
This is clearly adaptive--attributing success to internal factors builds your confidence and helps you perform better the next time. In the case of McGwire, it allowed him to use steroids off and on while minimizing anxiety that he'd perform worse without them.
As with Kobe, I wonder: Is McGwire's profligate self-serving bias merely an aberration? Or is it in fact one of the main reasons that he was able to have so much success in the first place?