Laterality, order of report and attention in a dichotic CV syllable task

Lateralisation was measured on a dichotic CV syllable-pairs task under 4 conditions: (1) free attention and report; (2) as in (1) but with subjects required to report location of items; (3) random pre-stimulus and (4) random post-stimulus cuing of the ear to be attended to and reported first. In (1) there were accuracy advantages for the right ear and for first reports after controlling right ear starting bias. After excluding intrusions there was an REA in accuracy for (2) but no starting bias; a similar REA was observed for (3) and (4) but the first report advantage for (2) and (3) was absent for (4) and (4) was less accurate overall. There were more intrusions for (4) and more from the right ear for (2), (3) and (4). Subjects with the highest intrusion rates from the right ear were also the most lateralised to this ear on the measure which excluded intrusions.