ERP time course and brain areas of spontaneous and intentional goal inferences

This study measured event-related potentials during spontaneous and intentional goal inferences. Participants read sentences describing the behavior of a target person from which a strong goal or intention could be inferred. The last word of each sentence determined the consistency with the goal induced during preceding sentences. In comparison with behaviors that were consistent with the implied goal, a stronger P200 waveform was obtained when the behaviors were irrelevant with that goal or did not contain goal-directed behavior at all, and this P200 showed considerable parallels between spontaneous and intentional inferences. This indicates that goals were inferred rapidly and automatically while reading the behaviors, irrespective of the participants' spontaneous or intentional instructions. In line with this, source localization (LORETA) of the event-related potentials shows predominantly activation in the temporoparietal junction (TPJ) during and immediately after goal detection (225-300 ms). Before and after this time interval, however, activation is stronger at the TPJ during spontaneous processing, and stronger at the medial prefrontal cortex (mPFC) during intentional processing. Memory measures taken after the presentation of the stimulus materials support the occurrence of goal inferences and show significant correlations with the neural components, indicating that these components are valid neural indices of spontaneous and intentional goal inferences. The results are highly similar to previous ERP research on trait inferences that revealed a similar division of brain activation for spontaneous (TPJ) and intentional (mPFC) processes, but appearing later at about 600 ms, pointing to similar brain areas recruited for social inferences, but at different timings for different inference types.