As you learn in biking, the position and velocities of objects changes smoothly, but awareness of the position and velocities of objects can change very discontinuously.
It's a joke - the real world is generally continuous at the scales of our perceptions, but our perceptions can make errors like not seeing a car off to the side then suddenly becoming aware of it and swerving or screeching to a halt. I think it comes under the rubric of "if you took calculus and then pay attention to your own life."
It's actually real. IIRC, our eyes and focus move not smoothly, but in discreet jumps. Objects can be overlooked. I think I read that they train professional 'drivers' like pilots how to compensate.
: ) Sure but many jokes are real. And the saccades are not really the problem with biking, but the attention and the tendency to pay more attention to internal thoughts more distant from sensory streams than the immediate content of the sensory streams. https://en.wikipedia.org/wiki/Saccade
