Which principle states that if you don't use it, you lose it?

The principle that aligns with the idea of "if you don't use it, you lose it" is closely related to the concept of memory decay, which reflects the notion that information stored in memory may fade or weaken over time if it is not actively recalled or utilized. Trace decay theory specifically posits that memories leave a trace in the brain, and if this trace is not reinforced or activated through use, it diminishes over time. This suggests that memories require rehearsal or retrieval to maintain their strength and accessibility.

In the context of how memory works, understanding this principle highlights the importance of practice and engagement with the information to ensure it remains retrievable and useful. Regular retrieval of memories, such as through studying or discussing learned material, can help solidify these memories, preventing decay and loss.