Just want to point that the bystander effect (like many classic theories in psychology, it seems) could not be replicated in a real-world study: https://en.wikipedia.org/wiki/Bystander_effect#Counter_examp...
In real life, many people really do jump in to help when they know help is needed.
No OP, but bystander effect is definitely real.
*Anecdotal example* : got immediate response for my email after addressing specific person. This was after repeated appeals for help/response to entire team on same email chain.
I can relate to that as a Latin American working in Europe; in the USA specifically this balance is way easier to find and there are more checks and balances.
My first year here I came from this Humanistic Mindset which is the standard in America as a whole; however being in EU I found out that most of the people run (not are, but run) in this Mechanistic Mindset.
Initially makes sense because when you have a a different background, the best you can do is equalize the communication style.
Someone said something interesting about those differences that relate to the article: In the US the culture is more or less like a salad, where maybe all the ingredients are sliced but more or less you know each one, and the result is something good. In Europe, the culture is more like a soup or a Fundue where differences are below the water but the surface is homogeneous, or all the ingredients are melted together.*
* N.B: I do not have a horse on this race or any preference over another.