Smallwood (2013) made important contributions to the science of mind wandering by distinguishing
between 2 aspects of the mind-wandering experience: (a) how the mind wanders, which entails the
process of maintaining the continuity of a mind-wandering episode, and (b) why the mind wanders, which
refers to those mechanisms that lead to the occurrence of a mind-wandering episode. This new
process– occurrence framework offers a way to compare and contrast existing theories of mind wandering
and highlights key questions to be addressed in future work; however, we suggest that in characterizing
one of the core mechanisms of mind wandering, Smallwood conflated the occurrence of a phenomenon
with its explanation. Specifically, the occurrence of perceptual decoupling (i.e., that mind wandering is
associated with reduced attention to external stimuli) was conflated with an explanation for its occurrence
(i.e., in order to insulate the internal train of thought). Disentangling the theory of perceptual decoupling
raises questions regarding both its role in insulating the internal train of thought in mind wandering and

its unique theoretical contributions to the how/process of mind wandering.