This article examines American military veterans’ metacognition – their ‘thinking about thinking’. After sustaining mild traumatic brain injuries (mild TBI), some veterans experience impaired memory, poor concentration and other cognitive problems that surface when they begin attending colleges and trade schools. In response, clinicians at a specialized TBI clinic at a Department of Veterans Affairs (VA) Medical Centre created a programme that encourages veterans to become reflexive about their cognition. Symptoms that veterans experience as cognitive impairments are reframed by clinicians as conflicts between their military-minded bodies and their new civilian environments. We have seen the growing influence of the neuro-disciplines on the government of populations, but newly materialist understandings of the mind also shift the boundaries of what constitutes ‘the body’, suggesting new terrains for the disciplinary techniques of institutions. Analysing veterans’ experiences of their injuries and clinicians’ efforts to help them reveals cognition as a site of discipline.