When Will the Brain of an Immortal Human Run Out of Memory?
They would live forever, so the concern is on the memory of their brain in the long run.
In the view of computer science, our brain is a hard disk, where we can write and read memory.
While it is good to keep as much memory as possible, there are some drawbacks that prevent our brain from doing this.
First, access to memory will be difficult. As the volume of our memory increases, positioning a specific memory requires much more effort, which leads to a longer path of memory access.
Next, the energy consumption for memory storage will be very high. Maintaining the storage of memory in our brain requires energy supply, which is limited in our brain, as explained in my another blog post:
What will happen if we increase the number of neurons in our brain?
Thus, our brain may be specialized for memorization, in the cost of not performing well in other cognitive activities, which is explained here in the section “ Handling of variable workload”:
With the drawbacks stated above, it would be better to keep a limited amount of memory, so our brain has developed mechanisms to organize memory.
One mechanism is deleting memories that are not useful, which cleans up spaces for new memory, another is to merge similar memories together, which reduces the volume of stored memory. In computer science, the equivalent processes are cleaning up and defragmentation of hard disk.
Those processes are done during our sleep, when our brain is under maintenance of itself. It is also true in computer science, when maintenance of hard disk is done during idle time of computer.
As our brain runs for a long time, we are keeping memories with higher values with our organization, so it is unlikely that our brain runs out of memory.
