Different error types and error processing in spatial stimulus-response-compatibility tasks: behavioural and...

We tested the hypothesis that in spatial stimulus-response-compatibility (SRC) tasks two different error types occur: A noise-induced 'general error' independent of SRC and reaction time and a 'position driven error' in incompatible trials with short RT being driven by the irrelevant stimulus position. A second issue was whether error detection is different for these two types of errors, which should be reflected by differences in the error negativity (Ne), since the Ne is seen as a neural correlate of error detection. To study these issues, we used a Simon- and a spatial Stroop-task. In incompatible (vs. compatible) trials we found more errors and a below chance accuracy in fast responses. Neither the amplitude nor the latency of the Ne were significantly affected by the experimental factors. This pattern of behavioural results supports the above hypothesis of two error types in such tasks. The Ne results indicate that error detection is similar for both types of errors.