Scientific investigations of human thought usually equate it with only the deliberate, goal-directed mental processes that occur during problem solving and reasoning, while spontaneous thought processes that occur without individuals’ volition or direct control have largely been neglected. Given that spontaneous thought takes up as much as one-third of people’s waking lives, this other side of human thought is a crucial area for scientific inquiry. However, the lack of methods for immediate and direct observation of spontaneous thought in neuroscientific experiments makes their results ambiguous. Contemplative or meditation practice, which trains introspective observation of moment-to-moment mental processes, can provide the first-person expertise required for more precise investigations. Thus, rather than simply studying the effects of meditation on brain and behavior, the proposed neurophenomenology experiment will use both objective measures from real-time functional magnetic resonance imaging (fMRI) and subjective reports informed by contemplative practice to examine the underlying brain dynamics of spontaneous thought.