sentence: There are many laboratory experiments quantifying its strength in terms of localization ( e.g ., Alais & Burr , 2004 ; Bertelson , 1999 ; Bertelson , Vroomen , de Gelder , & Driver , 2000 ; Jackson , 1953 ) , though it would be of particular interest to know how much it influenced perception of sound sources in everyday life ( it would also be of interest to know its strength in hearing impairment or aided listening , as there are few , if any , ventriloquist experiments which have used such listeners ) .