Straight (constant chord) wings tend to stall at the root first, highly tapered wings tend to stall the wing tips first. Many full scale airplanes have "stall strips" on the leading edge of the wings at the root, these are there to make sure that the root stalls first. When the wing tip stalls, a snap roll is the result. If the wing root stalls first, the airplane usually just mushes and then drops it nose.
When a wing tip stalls, the loss of lift at the tip causes that wing to drop. The resulting roll changes the direction of the apparent wind causing the angle of attack of the dropping wing tip to increase even more, cinching the stall. This same roll reduces the angle of attack of the unstalled rising wing preventing it from stalling. Full up elevator gives the unstalled wing the angle of attack it needs to roll the plane very fast.
Ways to prevent tip stalls include making the leading edge of the wing sharp at the root, this encourages the stall to happen at the root first. Building the wing with washout, an intentional wing twist that has the wing tip flying with a lower angle of attack than the root. Washout has other advantages as well. It reduces drag by reducing the severity of wing tip vortices.