Thijs Verwijmeren and his colleagues exposed 173 students to the name of a drink brand (7-up or Nestea) for just 17ms, far too quick to be consciously detected; or if they were in the control group, no brand was shown. Crucially, for those students shown a subliminal brand name, half had been given a prior warning that they were going to be exposed to a subliminal message and that such messages can affect behaviour. Finally, all the students made a hypothetical choice between two drinks – 7-up or Nestea.