People are ‘handy’, we use our hands all the time. Being on just two legs makes us wobbly, so if we lose balance, we stick out a hand or two to correct it. This is firmly lodged in our brain. So if we sit on something as wobbly as a horse, and someone gives us reins in our hands, we use them immediately to steady ourselves.
Reins are attached to a bit in the mouth. Pressure on a bit gives an unpleasant feeling. Horses react by sticking their tongues out or opening their