Event-related potentials in the dual task paradigm: P300 discriminates engaging and non-engaging films when film-viewing is the primary task.

Five groups of subjects (11-16/group) were run in three experiments. In each study P300 amplitude and latency were studied as a function of three sensory task conditions: (1) baseline (oddball task: target and non-target tones only); (2) boring film viewing plus oddball task; and (3) exciting film viewing plus oddball task. In Experiment I, target probability was P = 0.22. In Experiments II and III, each of two groups of subjects was run at P = 0.22 or P = 0.33. Two different exciting films and two different boring films were used. Oddball-target amplitude was found to consistently decrease from baseline to boring to exciting film-viewing conditions at P = 0.22. At P = 0.33, the 2-film discrimination was successful in one of two experiments. P300 amplitude consistently differed from baseline to film-viewing conditions. For the non-target (frequent) tones, the smaller P300 amplitudes consistently discriminated boring and exciting films, as well as single from dual tasks. For target P300 latency, single (baseline) and dual (film-watching) conditions were always discriminable, but boring and exciting films were not discriminable. There were no effects on non-target P300 latency. N100 amplitude discriminated baseline and film viewing conditions, but not boring and engaging films.