Fair coins tend to land on the side they started (2023)

I wouldn't be surprised if there is something to it, but I suspected they didn't use legitimate coin flips (because it seems like a large amount of people can't really flip a coin), and looking at the videos confirms it, at least for the flips done by Bartos:

https://osf.io/6a5hy/

They're very low RPM and very low time in the air. Nothing I would accept for any decision worth flipping a coin for.

That's not tossing a coin, that's barely throwing it in the air.

To me this kills the credibility of the entire study and of the authors.

Sure, there may be something to it, but people will have a very different thing on their mind unless they check the video, which I wouldn't have done without your prompting.

It's unlikely they don't understand how misleading it is.

And somehow I have the intuition a proper coin toss will not exhibit the same properties.

This was my first objection as well. However, if most people flip coins like that, then the measurements are valid -- the conclusions are about what average people will do, not a perfect mechanical coin flip. Otherwise you're falling in the no true coin flip fallacy.

Yeah, if I'm actually forced to use a coin instead of a computer system, I try to ping the thing off the ceiling and at least one wall (not in that order). Hitting various other things is a benefit, not a downside.

Is it unlikely? If I didn't read your comment I wouldn't see any problem there. I never saw anyone flipping a coin in a different way. It's just not done much around me.

The guy in the grandparent YouTube video suggests shaking the coin in a closed hand (or better, a box) to randomize the starting side and then transferring it unseen to someone else to flip it

Craps is also brought to mind where the dice have to bump the back wall

a coin is likely to land on the same side. it was flipped from if it was tossed by a machine at low RPM and height consistently*

there's your paper

but they did?

here's the video https://youtu.be/-QjgvbvFoQA?si=ZTT1LWWJC8T4LIQZ

I'm sure you will find similar behavior with dice if you just gently let them fall from your hands instead of throwing them across the table.

This is silly.

Let's abandon coin flipping in favour of coin shaking then

If you claim to do a research on coin tossing, the minimum is to be aware on how people toss coin.

The whole purpose of tossing a coin is randomness, so of course you want high and fast.

If the result was that no matter how high and fast you throw is you get this bias, it would have been interesting.

But now you just say "if you do things badly, things don't work".

Somebody’s grant money getting thrown down a hole…

No, the whole point of the paper (and the physics model it is verifying) is to see what happens in normal human coin tosses.

If you want to measure what happens specifically with high and fast coin tosses, then that’s an entirely different study to be done.

It's a shake and then a flip. Put your hand on your hip and bend your knees in tight.

I don't know what a normal human coin toss is. Does the paper contain evidence/argument to justify their way of flipping a coin as "normal"?

That still sound valuable if people generally tend to do it badly? If only to provide an argument for doing it properly.

That's the "the video", that's a video by a third party about the study, and it doesn't include all footage or all participants.

The comment you replied to links to footage of one of the participants. You can see in that footage that the coin hardly leaves his hand.

I think it's still noteworthy that what many people consider a "fair toss" is not in fact a fair toss. In other words it's interesting from an applied psychology perspective even if the physics of the phenomenon isn't particularly interesting.

Your point about the coin hitting other things to be more unpredictable reminded me of an interesting blog post[1] about generating cryptographically secure random numbers. The memorable part for me is the suggestion of using five coins of different shapes and sizes so they get shaken a consistent number of times in a large cup.

[1]: https://blog.sia.tech/generating-cryptographically-secure-ra...

This makes me feel like, similar to everything else, even science is actually a spectrum. Based on how much insanity to put into the testing.

Even if the testing was as many flips as possible over years and years of automated means, with a flipping machine that varies flipping power and angle, and detecting sub-millimeter wearing on the surface of a coin, and every single coin style/size in existence, of every single wear level possible from all positions and angles, through every different combination of typical earth-based air percentages... What does the result really mean? It doesn't actually come up with a "conclusion", its just an accounting of an exact series of events. You will still never use that into the future, you will still describe the act as having a probability of outcome.