Locard's exchange principle

“In forensic science, Locard's principle holds that the perpetrator of a crime will bring something into the crime scene and leave with something from it, and that both can be used as forensic evidence.” (Wikipedia)

Every contact, every interaction, is an exchange. You leave something, you take something. Once you see it like this, you can have much more agency and control over what you’re leaving and taking.

News example:

If you look at the news from this perspective, you realize you’re basically always leaving with outrage or sadness or any other negative emotion, and rarely with anything truly useful. And on top of that, you’re exchanging your precious time and energy. So then you have some options:

1. Quit the news because it’s a bad exchange
2. Change the dynamics of the exchange to make it valuable for you:
   
   1. Leave as little as possible in the exchange: so cut your time from 30min to 3min. Summarize, only get the actually useful news for your niche or daily life, not “4 people stabbed in a distant country you’ve never heard of”
   2. Take as much as possible from the exchange. There are many ways to go about this, but I like this one anecdote from a Finnish comedian. As he was learning the craft, he used to look at 3-5 news headlines every single morning, and shifted and rearranged and reformulated that story until it became funny – a bit that he could actually use in a comedy set and get laughs. “What if I turned it upside down? What if I exaggerated it to the max? Imagine if this same situation happened in a completely different context?” Like a rubik’s cube, he would keep on looking at the headline from different angles and reordering and tinkering, until it clicked and something valuable was born.

Most discussion about the news is either “it’s shite, just cut it out”, or “democracy dies in darkness, it’s your civic duty to stay informed”. Once you apply Locard’s principle, you unlock the secret third option.

Personal relationship example:

Although many people believe viewing personal relationships from an exchange perspective makes them transactional, and that’s not what relationships should be – I still think Locard’s principle is worthwhile to consider in this context. It can actually help you gain deeper relationships, not shallower.

For example, consider when a friend or acquaintance texts you, they usually don’t text you “just because”. Especially if we’re talking about real texts, not just someone sharing a meme with you. They are reaching out for a reason. What’s the reason? What’s really on their mind? What would make this conversation an excellent exchange for them? Are they looking for reassurance, or for someone to give them the hard truth? Are they looking to reconnect and get closer with you? – in this case, what are the best ways for you to deepen your relationship?

In other words, take a second to figure out what is the most valuable thing you can give in this exchange. (And often we do this very intuitively, but still worthwhile thinking consciously!)

Or if you flip it, when you are reaching out to someone. Especially in a professional environment or seeking for advice, I think it should be mandatory to not waste people’s time or have them guessing. Just outright tell them: “the most valuable thing you can do is help me with x”. “Give me an answer or your opinion on x and that makes this a great interaction for me.” Most people would like to help, but you need to make it very easy for them.

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There are some people you meet who you just know are always calculating. Always making mental notes. You drop one hint of something, and you have no doubt that they got it. Interactions with these people tend to just be sharper. Paul Graham talked about this.

(I have a secret theory that this is how you probe innate intelligence in children, or why not adults, but my sample size is too small and it's too hard to actually study for real.)

I don’t know what is the real cause of this, but probably Locard’s principle is linked to it. When I put on my corporate work hat, I tend to be super sharp with every interaction, particularly with my higher-ups, because I know there’s an exchange at play. I’m trying to extract any indication of strategy or competitive edge so I can perform better, while looking to leave the boss with a more positive impression of me. And I guess that’s partly what makes corporate life stressful, because the higher you climb, the more every little thing is under scrutiny.

But outside of a professional context, you see this sharpness a lot in dating and flirting – the other context where stakes are high. Charisma and wit is really just a sharpness to the information you receive. Showing interest in someone is really just a sharpness and keen attention to what they are saying, and then showing that you took notes.

• Wikipedia