Library and memories

If the human brain is a processor how and where does it store memories? Does it have a dedicated storage space? Essentially, how do we store and retrieve information about the past? From a physiological standpoint, this Forbes article will give you a good idea of how that works. This post is focused more on the methodology.


Chain of events

Try to remember what you did between 3:30 PM and 4 PM on Tuesday last week. How did you go about remembering that? Chances are that you thought about what you did in the afternoon as a whole that day, i.e. from 12 PM to 6 PM first. Within the stuff you did during that period, you can find information about what you did between 3:30 PM and 4 PM. You can confirm that that’s exactly what you did by leaning on the logic between the information recorded before and after that time period. An example would be:

  • 3 PM to 3:30 PM — traveled to work
  • 3:30 PM to 4 PM — had coffee at the coffee place near work
  • 4 PM to 5 PM— working

You can agree that there is logic in this chain of events. If you remembered something else like walking the dog in the park at 3:30 PM, it wouldn’t fit with the logic of the other information. Having reference points allows you to validate which memory fits where and confirm if it’s true or false.

Before I try to clarify this, I have to make sure that you have an idea of what the blockchain is and how it works in a nutshell. Here’s an explanation:

A blockchain is a digitized, decentralized, public ledger of all cryptocurrency transactions. Constantly growing as ‘completed’ blocks (the most recent transactions) are recorded and added to it in chronological order, it allows market participants to keep track of digital currency transactions without central recordkeeping. Each node (a computer connected to the network) gets a copy of the blockchain, which is downloaded automatically. Nodes spread bitcoin transactions around the network. One node will send information to a few nodes that it knows, who will relay the information to nodes that they know, etc. Much like word of mouth. Some nodes are mining nodes (usually referred to as “miners”). These group outstanding transactions into blocks and add them to the blockchain. Doing so creates an indelible record that cannot be changed; furthermore, the record’s authenticity can be verified by the entire community using the blockchain instead of a single centralized authority.

The explanation above talks about cryptocurrency transactions. Because of that, people often assume that the blockchain is only relevant to finance. They’re wrong — it’s a general method of recording information. Cryptocurrency transactions are also bits of information. So in other words, a blockchain is a publicly available record of information that is linked together by the order of which it is included in blocks and its authenticity can be verified by everyone that has a copy of it.

Now think about the way you remembered what you did between 3:30 PM and 4 PM two days ago. The 3 activities — going to work, having coffee and working represent transactions holding bits of information about events stored within a larger batch of information that we’ll call the afternoon block. That block contains transactions from 12 PM to 6 PM. It is linked to the morning block of that day (8 AM to 12 PM), which is linked to the evening block of the previous day and so on. You get the idea. This chronologically connected chain of past events is a form of blockchain; each individual’s copy of that blockchain differs from that of other people — we’ll call the individual’s blockchain of historical information, his own personal memory chain. So in essence, you accessed Tuesday’s afternoon block on your memory chain and found the bit of information timestamped 3:30 PM to 4 PM.


Blockchain example


Let’s imagine now that your boss asks what you were doing between 3:30 PM and 4 PM because someone stole $100 from the store within that time period. Because he’s looking for information he doesn’t have, he requires access to your memory chain to see what information you stored. You access it and read out the information —” I had coffee from 3:30 PM to 4 PM”

If you are the only one that can confirm that exact piece of information (I had coffee at 3 PM to 4 PM on 25.04), i.e. no one else was there to see you drinking coffee, your version of the truth is valid by default. Your boss agrees with it because he can’t prove otherwise. It’s “proven beyond reasonable doubt” in law terms. This is an example of a centralized system — one node has 100% authority to validate the truth.

Now let’s imagine that you saw your colleague steal the money and no one else did. Both your memory chains have the same bit of information timestamped 3:30 PM to 4 PM — X stole $100 from the store. Your boss brings you together and asks each of you who did it. Game Theory aims to explain the various possible outcomes of this question based on incentives, but since I’m trying to explain how the blockchain of history works, I will stick with a simple binary version:

  1. You reach consensus. Both of you state the same thing. This can be either the truth or a lie.
  2. You disagree. You present two conflicting bits of information and the likelihood of each of them being true becomes 50%.

Being the only two people with that bit of information stored in their memory chain, you are the only ones that can verify which version is true and which not — who stole the cash. In blockchain terms, you are a network of two nodes that can spread and validate that information. If you tell one person each, you share information with other nodes that you know. Now there is a total of 4 people (nodes) that have that information and can validate it if necessary. If asked, however, it’s 50/50 again because of 2 of the people will say it was you and 2 will say it was your colleague. This is a decentralized system in disagreement.

It such scenario, your boss has to pick a side — he would usually go with the version of whomever he trusts more. The version of the information of the more trustworthy person or group of people becomes the truth. If your boss trusts your colleague(s) more than you, you get fired for doing nothing wrong. The wrong information is shared with other nodes as a result — other colleagues, police, and family now believe that between 3:30 PM and 4 PM in that store, on that day, $100 were stolen by you. This is the problem with trust that blockchain aims to solve.

Now imagine that many people saw your colleague steal the $100. Because information is now distributed, the truth is recorded in many copies of the memory chain. The more the people that can validate the information, the harder it is for a bad actor to establish a false version of it, because he has to convince 51% of them to lie.


Blockchain in essence

Every society stores important information about itself on this principle. The whole of history, from the beginning of time to this very second, is one huge blockchain in essence — it represents information about past events, which are timestamped and linked together based on which event occurred when. You’ve probably heard the term “collective memory”. Think of the collective memory of your country — it is a memory chain shared by the whole nation. We call it history. Trying to alter that memory chain would require the majority of the people to agree on the change. If they do, history is rewritten, if they don’t — history remains as it is.

Our world has never been more interconnected. The amount of information that is available is absolutely huge compared to 100 or even 20 years ago. Our brains haven’t had the opportunity to evolve enough to store all of it. As a result, we go through a cherry-picking process of including only the most valuable information in our memory chain — it is often the moments that have resulted in an unusual amount of emotion that get stored there. For everything else, we turn to other nodes in our network; 20 or 30 years ago the only other nodes in our networks were our closest people and a few media outlets. Today, we have the internet — a huge network of nodes that is extremely hard to manipulate, but unfortunately, not impossible. Fake news is an example of this.

To recap, the idea of the blockchain is not new. Humans have been storing information about past events on that principle for a long time. The only difference now is that the digital blockchain enables anyone who’s part of the network to witness, record and validate information on it. With each increase in the number of nodes in the network, the harder it gets to control 51% of them and include false or amend information on the blockchain.

In the non-digital world, the nodes responsible for building and maintaining the public record are journalists, historians, and institutions. Since they’re not numerous, it’s far easier for a bad actor to control 51% or more of the nodes and include false information on the blockchain. Financial institutions, for example, are the only ones that have a complete record of all transactions, meaning that they can tamper with it, without the knowledge of the average individual. Trusting them or not is not the case here — what’s important is that they have the ability to do it. Bitcoin’s blockchain — the first digital blockchain to enter the real world — makes it practically impossible to do so.

Sources: Investopedia, Coindesk

Notice from the team: Please note that the author did not benefit in any way from writing this article. He should not be associated to any extent with Infinite X Labs. Writing articles is purely a work of heart for Dimitar.