Welcome to Long's DDM tutorial!
The drift-diffusion model has been widely applied to studies of decision making, thanks to the pioneering work of Ratcliff and others. With just a few parameters and a conceptually simple process, this model can describe behavioral performance (choice and reaction time) for a whole range of tasks (in humans and animals). As I have learned over the years, however, it is not always straightforward to intuit a prediction from the "simple" DDM; the best way to develop better intuitions is to play with simulations. This tutorial is intended to make it easier for anyone to play with the basic DDM, without having to write/debug code.
I hope you find this tutorial helpful.