Well, after five episodes, Touma finally figured out that there’s no way Index’s brain would explode (or implode?) because she has too much stuff memorized. I admit that I didn’t think anything about Index having too much information, but that was only because this is anime.
So after watching this episode, I started wondering how much information the brain could hold. From my high school days, I learned that we only use about 10% of our brains and that geniuses still only use a maximum of 15%, but this information was for processing power rather than information storage. A search on google for brain capacity turned up results ranging from 100MB (~10^8 bytes) to 10^8432 (that’s a 1 followed by 8432 zeroes). With such a wide range of predictions, it’s obvious that no one knows how much information the brain can hold.
The way I see it is that there are real people out there with photographic memory and they live just as long as a normal person. Now, the human eye contains approximately 4.5 million cone cells (to distinguish colour) and 90 million rod cells (to detect light). Lets also say the brain can only interpret images from the eyes at 100fps and only remembers what is seen in colour. A 9 million pixel image (4.5 million cone cells times 2 eyes) would be about 3MB, so in one second the brain of someone with photographic memory would store 300MB of visual data. That means in 80 years, the brain would have stored over 700000TB of visual data.
Considering the average movie is 700MB, then a book should take considerably less storage space and there’s no way that only 103000 books would take up 85% of someone’s brain capacity. So the point I’m trying to make here is that the main character in Toaru Majutsu no Index (Touma) is too dumb and he’s slowing down the series by taking until episode 5 to figure out that Index won’t die from memorizing too much :P
Note: I know the brain doesn’t work in 1’s and 0’s so using bytes to measure brain capacity is wrong but hey, this is my blog and I can say whatever I want :)