3.3.3.e Comparison between groups

As all participants underwent the same experimental protocol, it is interesting to compare their performance according to their group. Although the tinnitus-simulated subjects were significantly younger than the other participants, they were all recruited according the same auditory criteria (0 +/- 10 dB HL until 2 kHz, maximum hearing loss of 30 dB HL over 2 kHz). Therefore, we allowed ourselves to compare them. Analyses of variance were performed on CRs and RTs for all subjects with the group (CO, BT, RT, LT, RSIM, and LSIM) as between-subject factor; the ear of the task (RE/LE or LE/RE), the stimulus S1 type, and the inter-stimulus interval were the within-subject factors.

Like the results observed for the three separate experiments, the ANOVA on CRs revealed the classical attention capture. First, participants responded more accurately to S2 after the presentation of a standard S1 (CRs = 91.77, SD = 10.38) than after the presentation of a deviant S1 (CRs = 89.45, SD = 11.50), F(1, 54) = 36.725, p < .0001. Second, the main effect of the ISI factor, F(2, 108) = 4.56, p < .02, showed that they performed better with the 150 ms ISI (CRs = 91.24, SD = 10.89), compared to the 100 ms ISI (CRs = 89.99, SD = 11.34), but no difference between the 150 and the 200 ms ISI (CRs = 90.61, SD = 10.77) was observed. Third, these two factors interacted, as revealed by the stimulus S1 type by ISI interaction, F(2, 108) = 81.797, p < .0001. Contrast analyses revealed that participants responded more accurately to S2 after a standard than after a deviant S1 for the ISI 100, F(1, 108) = 232.227, p < .0001, and for the ISI 150, F(1, 108) = 9.676, p < .01; but, conversely, they responded more accurately after the deviant than after the standard S1 for the ISI 200, F(1, 108) = 5.988, p < .02.

ANOVA on RTs showed the classic attention capture effect which we would not report in detail again. But, in addition, they revealed a main effect of the Group: the CO (CRs = 704, SD = 127.19), RSIM (CRs = 591, SD = 84.80), and LSIM (CRs = 666, SD = 128.67) participants responded faster to S2 than the BT (CRs = 760, SD = 168.58), RT (CRs = 745, SD = 99.73), and LT (CRs = 769, SD = 109.84) patients, F(5, 54) = 3.554, p < .01. Moreover, the effect of S1 type was varying with the ear of the task, as revealed by the stimulus S1 by Ear interaction, F(1, 54) = 8.090, p < .01. We performed contrast analyses to compare the difference between RTs after a standard or a deviant S1 for each ear. They revealed that this difference was larger when the task had to be performed in the right ear (LE/RE) than when it had to be performed in the left ear (RE/LE), F(1, 54) = 8.24, p < .01, although both differences reached the significance.