Originally Posted by wphamilton

No, that doesn't follow, neither of the bolded fragments.

First, the people putting on helmets did not experience higher risk. They did not ride slower. They did not "perceive" any difference in risk levels. The study acknowledged this explicitly.

Second, the people who "routinely wore helmets" also did not experience higher risk when wearing a helmet. They "perceived" a higher risk when taking it off, which does not mean that there was an actual higher risk experienced. Just a feeling. They did pedal down the 1/4 mile hill more slowly, immediately after taking the helmet off. If anything, it confirms that "feeling" of higher risk but nothing more could be concluded. It does not follow that they would ride faster when they put the helmet back on, other than on the immediate 1/4 mile hill.