Decay theory is a psychological concept that suggests memories fade over time if they are not accessed or rehearsed. This theory posits that the strength of a memory decreases as time passes, leading to forgetting. It emphasizes the role of time in the retention of information. According to decay theory, the brain's neural connections weaken when memories are not revisited. This can explain why people may struggle to recall information learned long ago, such as facts from a history class or details about a former job. Regular practice and retrieval can help strengthen these memories and combat decay.