Figure 1.
Examples of stimulus pairs used in the experiment.
C: color, S: shape,+indicates a match, - indicates a mismatch.
Figure 2.
A graphic illustration of the predicted outcomes of the current study from a response competition model and a confluence model.
In a response competition model, detection of the internal mismatch and the response judgment occur simultaneously, whereas in a confluence model mismatch detection occurs before response judgment. Both models predict that an internal mismatch is computed automatically regardless of whether it occurs in task-relevant or task-irrelevant dimensions. In the current study both models would predict color congruency and shape congruency main effects but no color congruency × shape congruency interaction at the mismatch detection stage. Both models would also predict facilitation (faster reaction times and corresponding ERP signal) of “same” responses when the information in the task irrelevant dimension was congruent and interference (slower reaction times and corresponding ERP signal) when it was incongruent. Additionally, both models also predict facilitation of “different” responses by a mismatch in the irrelevant dimension and interference by a match in irrelevant dimension. The models differ only in the time window in which the interaction should be observed. The Response Competition model predicts that the interaction effects would be observed in the same time window as the main effects. The confluence model predicts that the interaction effect should be observed after the main effects.
Figure 3.
The error rates and mean response times in the shape task and the color task.
Figure 4.
Grand average of the ERP data at the F5, Fz, F6, C5, Cz, C6, PO7, POz, PO8 sites for the C−S−, C−S+, C+S− and C+S+ conditions in the shape task.
Figure 5.
Grand average of the ERP data at the F5, Fz, F6, C5, Cz, C6, PO7, POz, PO8 sites for the C−S−, C−S+, C+S− and C+S+ conditions in the color task.
Figure 6.
Statistical significance of 2(task: color and shape) × 2(color congruency: match and mismatch) × 2(shape congruency: match and mismatch) ANOVA task at each time point at each electrode.
Figure 7.
Statistical significance of 2(color congruency: match and mismatch) × 2(shape congruency: match and mismatch) ANOVA task at each time point at each electrode in the shape task and the color task.
Figure 8.
The scalp topography and difference waveforms for mismatch detection.
a. The scalp topography for the difference waveforms between C−S+ and C+S+ at 236 ms and for the difference wave between C+S− and C+S+ at 260 ms. b. The difference waveforms between C−S+ and C+S+ and the difference waveforms between C+S− and C+S+ at the Fz site.
Figure 9.
ERP waveform analyses result for state congruency.
a. The ERP waveforms for the stimuli with congruent and incongruent response states (“same” or “different”) of the task-relevant and -irrelevant dimensions at CPz. b. The mean amplitude of the ERP responses to the stimuli with congruent and incongruent response states (“same” or “different”) of the task-relevant and -irrelevant dimensions during the 290–430 ms interval at CPz. c. The correlation between the ERP amplitude difference and RT difference revealed between the incongruent states and congruent states in the color task.