Software engineering involves writing new code or editing existing code. Recent efforts have investigated the neural processes associated with reading and comprehending code—however, we lack a thorough understanding of the human cognitive processes underlying code writing. While prose reading and writing have been studied thoroughly, that same scrutiny has not been applied to code writing. In this paper, we leverage functional brain imaging to investigate neural representations of code writing in comparison to prose writing. We present the first human study in which participants wrote and edited code and prose while undergoing a functional magnetic resonance imaging (fMRI) brain scan, making use of a full-sized fMRI-safe QWERTY keyboard.

We find that code writing and prose writing are significantly dissimilar neural tasks. While prose writing entails significant left hemisphere activity associated with language, code writing involves more activations of the right hemisphere, including regions associated with attention control, working memory, planning and spatial cognition. These findings are unlike existing work in which code and prose comprehension were studied. By contrast, we present the first evidence suggesting that code and prose \emph{writing} are quite dissimilar at the neural level.