I don't know. And frankly, I don't think that anyone does, even if assumers are extra eager to vomit certainty on the solution, and then wallow on their own vomit. [As such, take everything that I'm going to say with a grain of salt - it might be completely wrong.]

It's perhaps even impossible to avoid echo chambers, based on the article hinting that the formation of echo chambers might be actually a human tendency that goes beyond social media or online environments.

That said, I have two infographics for you guys. One explores echo chamber (circlejerk) formation from the inside; another, through enforcement of "higher ups". (Open the pics individually to enlarge them.)

If Lemmy is to avoid echo chambers, I believe that it would need mechanisms that:

• attract people with minority views
• discourage attrition between users with different views
• increase the visibility and accountability of selective rule enforcement (the public modlog already does wonders for that)

The federative nature of the platform already helps a bit, I think, since nobody got the power to meddle with the whole Lemmyverse. And the ability to defederate is also part of that, as you can selectively cut off instances trying to enforce some echo chamber, that helps to protect minority views.

I also think that echo chambers are often further reinforced in social media through the cultural acceptance of three irrationalities, that might as well call "character flaws". They are:

• eagerness to vomit certainty. I think that reasonable = doubtful people coexist better with different points of views.
• oversimplification of complex matters. It's often a mechanism used to shun off everyone who doesn't think exactly in a certain way, as automatically defending the opposite view. ("You either like apples or bananas! If you say that you love bananas you're assumed to be an apple hater, REEEE!" style.)
• genetic fallacies ("[person] said it's chrue than its chrue lol lmao"). Because it's that sort of thing that the intellectually lazy use to brush off their doubt, so it tends to compound with both points above.