Neuroscientific research increasingly sparks the imaginations and hopes of policymakers. Whilst the diversity of assertive statements being made on the basis of neuroscience has been well documented, less frequently explored are more contingent discourses regarding studies of the brain. In this paper, we analyze how social policy and service actors discuss their engagements with neuroscientific terms, concepts and findings. These are mobilized, for one, to substantiate and enlarge the focus of existing policy-for example to attract funding for different target groups (such as babies, people who just retired, etc.)-as well as to help develop (new) policies and services. We show how, in so doing, invocation of the neurosciences can act to align "mutual imagined understandings" among policy actors, practitioners and parents. Tentativeness and ambivalence also figured within our respondents' accounts of the use of the neurosciences. They argued that research had to be simplified in order to make it relevant for wider stakeholders (including politicians), whilst simultaneously considering simplification problematic in some cases. Our analysis foregrounds the different complexities, ambivalences, reductions and instrumentalizations involved in policy and service engagements with the neurosciences, rendering challengeable any notion that (ideas about) neuroscientific research "determines" policy in a linear sense.