Certainly the controlling attributes affect the learning of that skill. Since there are some skills listed and STR then DEX and some DEX then STR, I think the first is more important to learning than the second. For my own use, I consider the first to be twice as effective as the second.That said, Attributes have other properties that help that are not connected to learning skills. Increasing STR increases the damage you can do with most weapons and also increases your chance to hit and penetrate.
As far as I know, no one but Sir-tech knows the precise rules.