Why does synaptic pruning make neural networks more efficient?

Synaptic pruning makes neural networks more efficient by eliminating excess, unused connections, which allows the brain to refine and strengthen the pathways that are actively reinforced by sensory experience.12

During early development, the brain rapidly forms a surplus of synapses—at times twice the number found in an adult brain. As an individual interacts with their environment, connections that are not stimulated or reinforced eventually weaken and are removed. By "pruning back" these redundant synapses, the nervous system transitions from a state of broad, unrefined connectivity to one characterized by specialized, highly efficient neural pathways. This process is a fundamental aspect of neuroplasticity, ensuring that the brain remains adaptable and capable of optimizing its function based on the specific sensory inputs it receives.12