While parents have long received guidance on how to raise children, a relatively new element of this involves explicit references to infant brain development, drawing on brain scans and neuroscientific knowledge. Sometimes called ‘brain-based parenting’, this has been criticised from within sociological and policy circles alike. However, the engagement of parents themselves with neuroscientific concepts is far less researched. Drawing on 22 interviews with parents/carers of children living in Scotland, this article examines how they account for their use of concepts and understandings relating to neuroscience. Three normative tropes were salient: information about children’s processing speed, evidence about deprived Romanian orphans in the 1990s, and ideas relating to whether or not children should ‘self-settle’ when falling asleep. We interrogate how parents reflexively weigh and judge such understandings and ideas. In some cases, neuroscientific knowledge was enrolled by parents in ways that supported biologically reductionist models of childhood agency. This reductionism commonly had generative effects, enjoining new care practices and producing particular parent and infant subjectivities. Notably, parents do not uncritically adopt or accept neurobiological and/or psychological knowledge; rather, they reflect on whether and when it is applicable to and relevant for raising their children. Thus, our respondents draw on everyday epistemologies of parenting to negotiate brain-based understandings of infant development and behaviour, and invest meaning in these in ways that cannot be fully anticipated within straightforward celebrations or critiques of the content of parenting programmes drawing on neuropsychological ideas.