[climber604]

Although it's science fiction, the second book from the "Three Body Problem" series by Cixin Liu offers an intriguing idea he labels as the "Dark Forest". The gist is that the primary motivation for all civilizations is survival and other civilizations are a threat. This Quora answer gives more detail, but I highly recommend reading the books; there are many compelling science-based ideas within it.

https://www.quora.com/What-is-the-Dark-Forest-Theory-of-the-...

[SZJX]

That's one way to go about it but it might be a bit simplistic and there's no reason why cooperation wouldn't work out for some civilizations as well. To completely hide one's signals is both hard to achieve and not necessarily beneficial. For example in ancient times there were blooming trades between empires which would not have been possible if every civilization just thought about hiding themselves. I was not a fan of "Three Body Problem" from its beginning.

[ssijak]

Why would anyone want to spoil the books for themselves?

[kerbalspacepro]

I spoiled this book for myself, and it was still fun. There was a lot of dramatic tension as I waited for all the characters to realize the horrifying things that lay in wait.