Explain why a reflex action, such as blinking when an object moves towards the eye, occurs more rapidly than a voluntary action.

A reflex action is carried out by a simple neural pathway that does not involve the brain. The sensory neuron carries the impulse to the spinal cord, where it is immediately transmitted to a motor neuron via a single interneuron. Because the impulse does not have to travel to the brain for processing, the pathway is shorter and fewer neurons are involved. In contrast, a voluntary action requires the impulse to reach the cerebral cortex, where it is processed and a decision is made before it is sent to the motor neuron. The additional time needed for cortical processing means a voluntary action is slower than a reflex action.