Comparison of target monitoring and two-ear monitoring dichotic listening procedures.

The dichotic listening performance of 40 listeners was assessed for consonant-vowel (CV) nonsense syllables with two procedures. One was a conventional two-ear monitoring task in which listeners attended to both ears and provided two responses for each pair of syllables. The ear advantage was described by % RE-% LE. The second was target monitoring, a yes/no task in which listeners attended to only one ear and listened for the presence of a target syllable. That procedure provided both hit and false alarm rates for each ear, and the ear advantage was described by P(C)maxRE-P(C)maxLE, which is insensitive to decision variables. Although both procedures yielded mean right-ear advantages (REA), the mean REA of +7.5% with two-ear monitoring was significantly different from the mean REA of +2.6% with target monitoring. In addition, although 62% of the listeners had a significant REA with the conventional procedure, only 40% had a significant REA with target monitoring. Decision variables, which are not controlled with conventional dichotic testing methods, may contribute to the ear advantage as it is described frequently in the literature.