How Much Information?

Have you ever noticed that people speaking Spanish sound like they're talking really fast? Does this mean they are able to communicate information faster than English speakers? One reason why Spanish sounds so fast is because more syllables are spoken per minute than in English. However, analysis has shown that each Spanish syllable contains less information than each English syllable, so the information per minute is almost identical.

But what about written language? The square format of Chinese characters appears to fit better into our central visual field than the longer, slimmer words of English. This led linguists to suspect that Chinese would be read faster than English. But experiments show that English readers can perceive seven to eight letters at once, compared to just 2.6 characters for Chinese. However, those Chinese characters are denser in meaning than the English letters, and so both languages have basically an identical reading rate of 380 words equivalent per minute. This suggests that what limits the speed of our communication is not language but our cognitive ability to process information.

But how can you really quantify information? Well, the smallest amount of information you can have is the answer to a yes/no question, like have you seen the movie Frozen? Yes or no, heads or tails, we can represent these single outcomes with a one or a zero. One binary digit - it's one bit of information. A roll of the dice has six possible outcomes, so three bits of information are required to cover all the options. To uniquely represent all 26 letters of the English alphabet requires five bits of information. But if you include lower case, punctuation, special characters, and numbers, that takes the total number of symbols to 95. So, you actually need seven bits of information to encode all these symbols. That was first done in 1963 as the American Standard Code for Information Interchange, or ASCII for short.

Now, as the next closest power of two, computers adopted eight bits as the fundamental unit of computation, and they called it the byte, where they intentionally replaced the i with a y so that it couldn't accidentally be confused with a bit. So how much information does it take to make you? Well, your entire genetic code is contained in the sequence of four molecules, represented by the letters T, A, G, and C in your DNA. Each of these four options can be encoded by two bits of information. Multiplying by the six billion letters of genetic code in your genome, and dividing by eight bits per byte, that yields 1.5 GB of information. So you could fit your entire genetic code on a single DVD with room to spare.

Now, your body has an estimated 40 trillion cells in it, and each one contains a full copy of your DNA. So you actually contain sixty zettabytes of information. That's sixty followed by 21 zeroes. Just to put this in perspective, by the year 2020, all of the digital information in the world is estimated to be equal to forty zettabytes of information. You could store all of that on 100 grams of DNA. That is less than you have inside your body. But now consider this: you share 99.9% of your genetic information with everyone else on Earth, meaning that less than one part in a thousand is unique. So, the information that makes you you could be stored in less than a megabyte. You could put it on one of these, a floppy disk, in case you don't know what that is.

In contrast, video can contain a lot of information. To specify the color of each of two million pixels thirty times a second for this entire video would require 100 gigabytes of information. But you can watch this video in HD on YouTube with just a thousandth that amount. Now, the reason you can send such a big video with such a small file size is because video, like Spanish, has a lot of parts that are redundant.

Hey Michael, you know what I've been thinking about.
What have you been thinking about, Derek?
Information.
Go on.
It's a physical thing.
It's embodied in actual objects.
How's that?
Well, you know, like the words we say, they are actual vibrations in the air, right?
They're not just concepts.
They are real physical things that you could measure and detect.
That's true, and they don't go away; they don't disappear even after they've, for instance, moved through the air.
Right. After we've said these words, they have actually interacted with everything around us.
So, you're saying that technically, I could look at the world, and if I knew enough about it and the position of its particles, I could trace back and extrapolate all the information that's ever occurred through them or at them?
That's right. You could in principle figure out exactly what we've said here, today.
Woah.

This episode of Veritasium was inspired by the book "The Information" by James Gleick. And you can actually download this book for free by going to Audible.com/Veritasium or you can pick any other book of your choosing for a one-month free trial. Audible is a leading provider of audiobooks with over 150,000 titles in all areas of literature including fiction, non-fiction, and periodicals. Now, if you've already read "The Information," you may want to check out "Surely You're Joking, Mr. Feynman" by Richard Feynman. It's my favourite book by a scientist. It is absolutely hilarious, and you will thank me for downloading it. So go, check it out. I want to thank Audible for supporting me, and I want to thank you for watching.