Evidence that the mismatch negativity to pattern violations does not vary with deviant probability.

OBJECTIVE

To determine whether the classic inverse relationship between the amplitude of the mismatch negativity (MMN) and deviant probability can be demonstrated to violations of a concrete rule pattern.

METHODS

In Experiment 1, oddball and patterned auditory sequences were presented with high (p = 0.16) and rare (p = 0.02) deviant probability. In Experiment 2, a slightly different pattern was presented with high, moderate (p = 0.08), low (p = 0.04), and rare deviant probability. In Experiment 3, deviants in the patterns from Experiments 1 and 2 were actively detected at high and rare probability.

RESULTS

In Experiment 1, the amplitude of the MMN varied inversely with deviant probability in both conditions. In Experiment 2, no effect of probability was observed. Experiment 3 supported the hypothesis that high deviant probability causes instability in the memory representation of the standard in the pattern from Experiment 1.

CONCLUSIONS

The amplitude of the MMN to concrete pattern violations does not vary with deviant probability.

SIGNIFICANCE

The amplitude of the MMN may not vary with deviant probability. Once a stable memory representation is formed for the standard regularities in an auditory sequence, further examples may not strengthen that representation.