> you don't know that you'll work out your problem in the process of explaining it. For me, the solution doesn't often arrive while I'm explaining the problem

> you don't know that you'll work out your problem in the process of explaining it. For me, the solution doesn't often arrive while I'm explaining the problem but I've had a strong correlation with solutions arriving shortly afterward. As others have said, for at least for some cognitive types (which include me), the process of verbalizing a complex problem activates alternate mental pathways. Explaining it requires curating the domain into what's relevant/not relevant to include, adequately defining terms, surfacing implied assumptions and transforming the mental structure into a linear sequence of explanatory statements. I think the other person actually being there, as opposed to talking to the duck, is an essential element. And I suspect the results tend to improve in proportion to how capable and experienced in the relevant domain the duck holder is - despite not even speaking. The reason is that when I'm thoroughly explaining something complex to someone I know well, that communication requires me to model their prior understanding of the domain, terminology and even the ways they're most likely to engage with the problem. Sure, explaining something to a random stranger who doesn't know the domain can be partially helpful but it's also inefficient because a lot of my mental focus will be spent on explaining enough of the basics to orient a domain novice. Explaining it to someone who not only knows the domain but who I know is smart in exactly the ways likely to lead to solutions, unconsciously forces me to model my knowledge of how they tend to solve problems like these. It's kind of like a turbo version of that old adage "Ask yourself how {experienced domain expert} would solve this".