First, I wanted to get down what I meant by unguided peer response and how students can learn from each other by osmosis rather than critique.
If we can imagine subjects close to our students' lives (and that's not hard if we get off the academic, evidence-based writing cliche), we can have students write meaningful essays about their lives and what they're thinking as they try to imagine who they are, what they're doing, and what they might do. Then we create a venue in which they openly and unrestrictively respond to each other as people communicating to each other. This isn't the guided response in which I have specialized for most of my pedagogical career. It's responding to what was said, not how it was said (although the how might merge with the what).
In my classes, I have ways of encouraging an even distribution of responses so that everyone gets read (by read, I mean gaining meaning through being responded to); still, some writers get more, longer, and more sincere responses, readers responding to them as people. My students notice (and I have them write about this) which kinds of essays get those responses (this has to do with vulnerability). They pay attention to how the most-responded-to writers wrote. And then they think about how they might have written and use that knowledge the next time they write--if they would like responses, notices of their existences.
I had other subjects, but I'm going to stop here. I think that what I've written above might inform our own lives, how we live, how we do or don't open up to each other and how we gain meaning by having others notice that we're alive.