Peers provide feedback that wouldn’t be there otherwise

This principle is fairly self-explanatory. Whatever learning you are undertaking, if you do it with peers you will get critiques, and if you learn alone you will not. Continuing on with my study group example, if I had been studying alone and then read my notes that said the pleasure region of the brain's scientific nomenclature is "the fun zone", I may have just trusted that and moved on. Even if my notes were incorrect, without a peer to provide feedback its likely I would have accepted that as the correct nomenclature. Studying with peers I might have told one of them that area of the brain is the fun zone, and then they could've corrected my mistake.

Another example of this came on the eve of me and Joe's first talk in Berlin. The night before we wanted to go over out notes and prepare, instead we ended up at a bar with a nice lady we met at the conference and P2PU friends. We then decided to practice our talk on them. We had a bunch of slides with all sorts of technical information, but before we even got past the first one, our audience was full of questions. They needed clarification on some of the grounding ideas of paragogy. We did not think to go into detail on those, because they were clear to us.

Thanks to the wonderful peer feedback we received, we re-worked the presentation and did it way better the next day. Even though we kept it simple and focused on the basic principles we still got lots of confused looks and questions. If it hadn't been for our peer feedback the night before and we'd done the speech as planned its quite possible no one in the audience would have understood our ideas and it would've gone horribly.