Brenda has a post on perception of meaningful choice which is very good (all Brenda's posts are good, so if you're not subscribed to her blog, you should correct this error).
In my own little design theory world, I tie this concept very closely to agency theory, since I've believe that in digital games there is no *actual* choice and you can't *actually* affect the system. All choices have been coded and all possible outcomes have been accounted for because the rules are very strict, so instead we create the illusion of meaningful choice.
That's not to say there is no such thing as emergent gameplay. There are things designers can do to make the possibility space so large that there's no way all possibilities to get from point A to point B could have been predicted by the designers. Such designs usually follow strict willing suspension of freedom rules: a few rules that are very consistent that will have obvious outcomes, thus creating a system that gamers can experiment in. However, despite the possibility space inside point A and B, those points almost always fixed. That's not really a problem, of course, depending on what type of agency you like in your games, but it is an inevitable outcome of how digital games work.