Final answer:
The human brain’s long-term memory is believed to have a near-limitless capacity, so it doesn't forget because it's 'full'. Instead, memories can become inaccessible due to interference, memory trace decay, encoding failures, and amnesia. The brain's plasticity also allows for memory consolidation and reorganization, aiding in the processing and retrieval of information.
Step-by-step explanation:
The question asks whether the human brain can reach a state where memory capacity is maxed out, necessitating the deletion or forgetting of old information to make room for new. Current understanding suggests that the long-term memory has a vast, potentially unlimited capacity for storing information. Short-term memory, in contrast, has limited capacity, famously delineated by Miller (1956) as the magic number 7 plus or minus 2, representing the number of items we can hold in our working memory at any given time.
Forgetting in long-term memory doesn't typically occur because the brain has 'run out of space.' Instead, forgetting can happen due to several factors that include interference, memory trace decay, encoding failure, and amnesia. Proactive interference occurs when older information impedes the recall of newer information, and retroactive interference happens when new information blocks the retrieval of older data. Hermann Ebbinghaus's forgetting curve demonstrates that memory loss happens quickly after learning but then levels off, indicating that the brain does not necessarily 'overwrite' old memories but may lose access to them over time.
Moreover, the brain's ability to consolidate and reorganize memories through plasticity provides alternative explanations for the brain's capacity to store and retrieve information. In severe cases, such as traumatic brain injury or disease, external aids like stick notes might be used to compensate for impaired memory functions, as seen in the case study of fading memory.