The same person before they went through the training.
For this instantiation I would bet that this commonly stated truism is false. I expect the other factors to dominate the comparatively small influence of increased calm. (And, incidentally, they also should so dominate. The expected payoff for engaging in unarmed combat changed excessively in the direction of “less extremely bad”.)
The proper comparison would be the same person now if counterfactually they hadn’t gone through the training. I’d expect most people to get less fighty with age after their teens no matter what.
The same person before they went through the training.
For this instantiation I would bet that this commonly stated truism is false. I expect the other factors to dominate the comparatively small influence of increased calm. (And, incidentally, they also should so dominate. The expected payoff for engaging in unarmed combat changed excessively in the direction of “less extremely bad”.)