Dihedral as a 'self-correcting' influence works because the lift generated by the surface acts near as whatsit at 90 deg to the surface producing the lift. With a dihedralled wing this means that the lift forces of each wing half is canted inwards somewhat, as seen from the front. (Or back). Imagine now that one wing is slightly lower than the other, you have the situation where the vertical component of lift is now slightly less for the higher wing (That is, the lift opposing weight). Therefore the lower wing will tend to raise until the lift forces side to side are the same. Try this with a flat wing and you will see that the vertical components stay the same no matter what bank angle the wing is at. An anhedral wing will see the higher wing have a greater lift component, ie it will continue to roll. Dihedral as direction control is relying on the secondary effect of the yaw (rudder) to effectively roll the wing as the wing on the outside of the yaw will 'see' the relative airflow at a higher angle of attack than the inboard, and so long as yaw is held, the wing will continue to roll. An aircraft needs to roll to turn. and this effect can be very strong, which is how you roll 'rudder only' models. For those who haven't tried this esoteric form of modelling the power of the rudder on a properly designed rudder/elevator model can leave you a bit breathless until you master the idea. I have a Flop Tite 'Headmaster' with an OS.32 which is about as much fun as you can have, accelerate vertically, rolling all the way.
Evan, WB. #12