His life work revolved around the mismatch negativity (MMN) first revealed in collaboration with Anthony W.K. Gaillard, and Sirkka Mäntysalo in reinterpretion of the prior findings of an early selective attention effect - discovered by Steven Hillyard - as a consequence of experiments that were carried out in the Institute for Perception TNO, Soesterberg, Netherlands, in the summer of 1975, by Sirkka Mäntysalo. MMN has been established as a scalp-negative component of the event-related potential or ERPs, as derived from recordings made electroencephalographically via electrodes attached to the scalp. MMN was shown to be elicited by deviant stimuli interspersed amongst a series of standards.