Fake headline. This is not the usual meaning of the word “synchronize”. As many other commenters here point out, this makes the story a non-story. Strictly speaking, the headline is true in that the heart rates “synchronize”, but not the heart beats, which I would think that most people would mis-read the headline as.
Agreed. The headline is fascinating the content is appalling.
PNAS reporting the shocking news that peoples heart rates tend to increase during the exciting part of a story and that an increased rate leads to higher correlation between subjects.
Edit: Without naming any author in particular - does anyone else spot a pattern whereby certain researchers consistently hype their findings to the point of borderline dishonesty?
In academia, you're often evaluated on "impact". So you have an incentive to be impactful, not truthful, and while many (most?) try to be honest in the content, hyping the title is an easy way to increase your metric (impact) while not having a very bad conscience because "everyone does it" and "the truth is in the contents, actually"
And even then, the actual rate itself is unlikely to synchronize, only the delta on the rate over time. You don't put a bunch of people in a room, tell them all a story, and they all suddenly have 65 bpm rates.
Not sure we can fault them if it is a justified true headline but we expect that 'other people' can't read.
Per the Wason selection task this is a great experiment to run, because if it isn't true then that's strong evidence many more complex theories relating to sync are likely to be false.
I agree with OP's point: the word synchronize implies that two things begin to share some common value. In this case, the heart rates share similar behavior (not ~exact BPMs), but I think most folks wouldn't choose the words used to describe this.
A more apt title might say "the changes in their heart rates synchronize".
I would not be surprised if under certain very specific conditions heart beats couldn't be made to synchronise.
For example doing a dance to music where muscles in the chest might 'nudge' heartbeat phases of otherwise very similar individuals into synchronisation.
It is after all pretty hard to make an oscillator which isn't affected by any environmental effects, and there is no reason to believe nature has managed it, especially when there is no real biological need to.
An alien visiting from another planet might not be aware that there's a correlation among humans in what they find exciting and that changes in heart rate correlate with excitement.
There's some synchronization effects in metronomes and in industrial equipment. If you have several things that can oscillate, perhaps not at precisely the same rate but close, and the motions reinforce each other when they do achieve the same rate, you can get surprising synchronization.
I was initially curious how this could happen with a heart rate; I could imagine some shared feedback mechanism for walking, or breathing, but a shared feedback for heart rate was surprising. Perhaps if they were touching, and there was some electrical or pressure-sensitive pulse? Disappointing that it's merely the delta between exciting and dull parts of the stories.
"Their heart rates change in unison" seems like a perfectly fine interpretation of "their heart rates are synchronized" that matches the observations. It is in fact what I expected when I read the headline. Maybe the headline could have been even more explicit, but I don't think it's intentionally deceiving.
I find your two quoted lines as vastly different. The first is accurate and the second is not. Synchronized means to happen at the same time. For a rate to be synchronized, I expect the same rate value at the same time (each person at say 65bpm). If the rate change is in sync, I expect the same rate of change value for each person (everyone is slowing their heart rate at 2bpm per minute). In unison means at the same time (but not the same value).
One headline means we are excited at the same time, the other says we mysteriously communicate the state of our heart to our neighbors.
Edit; a concrete example. Let's synchronize watches, you move yours forward quickly and I'll move mine forward quickly. Even though we moved in unison, we are not synchronized and showing the same time together.
I assume the ‘mysterious communication’ would be the cadence of the reader, which could have been a remarkable feat. Can we influence heart beats externally (indirectly), say with sound, and nudge it into holding a rhythm? The story can increase/relax it, so perhaps individualized broadcasts could theoretically be used to synchronize the beats precisely (in the second sense)?
A headline which gives people the wrong impression is still misinformation. It makes the world less informed than before, as people rarely read articles after reading the headlines.
Edit: And it is super important to point out this misinformation in the top comment to an article, so that we can correct as many people as possible. So stating that this is misinformation isn't just some pedantic complaining, it helps correct the view of a lot of people and maybe will help make more people think a bit before writing headlines.
