I’m working with Henrik Singman’s tutorial on how to use
rstan to fit a diffusion/wiener model. What I’d like to do is to manipulate the boundary separation (alpha) so that instead of it being a constant boundary over time, it should have a slope. In my specific case, I want the boundaries to become smaller and smaller so that the subject acts on less and less evidence as time goes by. (I could also simulate the same process by gaining the random-walk process over time.)
Now, I’m not quite sure how one could implement this. Would it be possible to only manipulate the model formula statement or would one have to start digging into the source code of
rstan to manipulate the Wiener function itself? That is, is this achievable without too much hassle? I’m having a somewhat hard time to understand where to begin here.