For some fun, try this:
1. get to a stop sign in your neighborhood. Stop.
Then, try to turn without turning your head at all.
2. At the next stop, try turning, with moving your eyes only.
3. at the 3rd stop sign, now turn your head and eyes.
Most don't even realize you turn your head - and your body, too. Did you notice that? Now try to turn your bike without turning your head, etc. You'll find out quickly that you MUST turn your head and your upper body to see where you are going.