Echo chambers are responsible for polarization if we define them broadly as groups that orient themselves towards similar values by listening to each other and not to other groups. This happens with friend groups over dinner, family reunions, and (for those who are religious) at religious events.

However, if we define it as necessarily something that happens in social media, I disagree with the notion that those echo chambers are responsible for radicalization. Notice I said “radicalization” rather than ‘polarization’.

Before, you’d simply gather around with your friends or family and discuss how the world is becoming more progressive. If your family happens to have regressive values, you’d complain about marginalized groups no longer being as marginalized. “Oh, the gays, they want to destroy the country by normalizing homosexuality”. The impulse to retain the values of a marginalized group (such as religious and racist zealots) motivates further cloistering and clustering.

Now, social media amplifies polemical voices that fiddle with your insecurities. If you’re a shy teenage girl, this might mean that you’re exposed to messages about how you’re ugly and poor. But if you’re not, it can be about anything. An effective technique is showing you your political enemy doing something threatening. “Democrats steal the election”, " Republicans burn a library because of LGBT books". This makes you want to engage with the content and watch more ads from the social media platform (Facebook, Twitter, YouTube). As a result, you spend more time reading about or watching videos about this threat (the insecurity-fiddling threat) and radicalize. These are the flat-earth YouTube rabbit holes. Or the toxic-masculinity red pill ideology rabbit holes. Or the fucked up terrorist rabbit holes. Or the hyper-religious and anti-democratic zealot rabbit holes. Or the racist rabbit holes. There are plenty. You can tell me which ones I’m missing. You probably know what I am talking about.

In other words, it’s not echo chambers that worry me. It is algorithmic manipulation to maximize engagement. That is a source of big trouble for the world. That is what we will have to deal with if we, as a world, pretend to live democratically.