What is the size of the human brain in bytes?

I'm working on the concept for a scifi project based around Brain Uploading. 20 Minutes into the Future type setting if you need a tech level, pretty soft on the scifi scale because its about the implications of the tech and its main application.

Here's my question'; assuming NO compression, how much data space would a copy of the human mind take up?

According to TOW ~7 minutes of HD Video is 1 GB- for the sake of simplicity, assuming our memories are at that level of fidelity (not visually but including other senses) that would make a year of memory ~7.5 terabytes. But obviously I don't remember every second of my 23 years of life, and the brain is not solely memories...

This article posits the brain could hold 2.5 petabytes of memory, but they've simplified the matter even more than I have.

So, computer engineers, neurologists, tropers, using whatever formula or pseudoscience you like, can you give me a plausible answer to the size of the human brain in terms of computer storage? I'm not an expert in computer anything, but I would like to make an attempt to scale things properly.

I'm not sure if I'll reveal this number in the story (bit of a techno-faff), but I did plan to scale the size of the computer banks and such that hold brains on it. Any estimates or additional notes would be welcome.

In strictly computer terms you are probably looking at exabytes at minimum.

Human vision far surpasses High Defintion, in my opinion. Hell, theoritically they even exceed Ultra-HD.

Brain is just that amazing. Unless you can replicate one, brain uploading is pretty far-fetched even with the processing power soon-to-be quantum computers possibly offer. As Major Tom pointed out, you're talking about exabytes.

My completely unscientific wild-ass answer is that we have no real clue how human brain memory capacity would translate to computer memory capacity because we really don't know how (as in "the manner in which") the brain stores memories.

Definitely exabytes at minimum.

Here's an idea. If copying/uploading brains is a large part of the setting, you might be better off coming up with an imaginary unit without mentioning a direct way of converting it to known units. You could call it a...I dunno, a psychobyte and say it's equal to the average storage capacity of the human brain. Avoiding a specific number of bytes could bypass the problem of getting the numbers wrong. Just a thought.

If you're doing this it would be wise not to specify something specific at all. Failing that, there's good advice there.

I'd guess hundreds of TB, or single-digit PB, at maximum. While it's true that a year of HD video is 7.5TB, the brain does not remember pixels; it remembers concepts, objects, and interconnections. All of these associations and references to concepts (because I only have to know what a chair is once) will be lot smaller than the corresponding video. Perhaps even orders of magnitude smaller.

(As an example, if I were to replace all 3-word phrases on the Wiki with indices into a giant table, I'd save at least 11kb on the phrase "Evil Overlord" alone, and that's without any sort of optimization. Though this is a bit of a guess, since I have no idea what the most popular 3-word phrase on the wiki is.)

edited 4th Aug '12 4:11:28 PM by Yej

@ Major Tom; alright, new word

@ resetlocksley; I actually really like that idea! But from what I understand scientists aren't big on vague averages when it comes to measurement units. I mean, seconds are measured with cold-storage caesium or something

@ Yej; A very astute observation, especially considering memories often tend to reference the same things...

Alright follow-up question; assuming an actual number is available, would the brain of every person be a uniform size, regardless of age? This seems highly unlikely.

And thanks very much for the answers so far! :D

edited 5th Aug '12 5:27:02 AM by CleverPun

Definitely not. The brain keeps on making new neural connections.

Exabyte, it really isn't that complicated.

The human brain on the other hand — I doubt that we could measure the data storage it has.

Well, I didn't actually mean it should be a vague average in-universe, just that not specifying a definite number to the audience might remove the potential for inaccuracy that you're likely concerned about. And thanks, I'm glad you like the idea. :)

I think it's incredibly difficult to come up with the size of the data held within the brain but what if you copied the brain pattern instead, something for which we can make a better estimate on?

You have about 85,000,000,000 and we need data held on each neuron, placement, position, connections and so on. Being incredibly detailed we could say a meg per neuron. So that means 85 000 000 000 megabytes of data.

The issue is that to pull any memory or such from this system takes processing time.

On the other hand, we can pull out all data, index it for quick retrieval and then we'd have to calculate how much data is stored in that incredibly efficient arrangement. I think I'll go with a "per year" estimate on data size.

So let's say you're conscious for ~16 hours per day, and sleeping counts as... 2 hours of data rather than 8 hours. You have your different senses.

(Time for some number ass pulling)

• Video data (this would include audio data): 11 GB/hour
• Smell data: 5-6 million receptors for smell, let's say a bit of data for each per second for whether it was activated or not (I think that falls within the activation/deactivation time and no compression of this data)... so this translates to ~0.7 MB/second (2520 MB/hour)
• Touch data: Let's say there's 10 million receptors in human skin, we'll say it's like ~1.5 MB/second (5400 MB/hour)
• Taste data: Let's say 5000 receptors here, and we'll put it at 2.25 MB/hour

The per hour data is then 18922.25 MB/hour, so per year 124319.1825 GB.

Let's say average human lifespan is 80 years...

• 9 945 534.6 GB / lifespan
• ~10 PB / lifespan

Human brains contain billions of neurons and can form trillions of connections between them. The storage capacity of the human brain is far greater than most computers, but it doesn't store information in the same way. When we remember something our brain recreates the memory rather than simply playing it from a recording, so the whole thing isn't actually stored in video form.