Characterizing an ERP correlate of intentions understanding using a sequential comic strips paradigm
Chronometric properties of theory of mind and intentions understanding more specifically are well documented.
Notably, it was demonstrated using magnetoencephalography that the brain regions involved were
recruited as soon as 200 ms post-stimulus. We used event-related potentials (ERPs) to characterize an
electrophysiological marker of attribution of intentions. We also explored the robustness of this ERP signature
under two conditions corresponding to either explicit instructions to focus on others’ intentions or implicit
instructions with no reference to mental states. Two matched groups of 16 healthy volunteers each received
either explicit or no instructions about intentions and performed a nonverbal attribution of intentions task
based on sequential four-image comic strips depicting either intentional or physical causality. A bilateral
posterior positive component, ranging from 250 to 650 ms post-stimulus, showed greater amplitude in
intentional than in physical condition (the intention ERP effect). This effect occurs during the third image
only, suggesting that it reflects the integration of information depicted in the third image to the contextual
cues given by the first two. The intention effect was similar in the two groups of subjects. Overall, our results
identify a clear ERP marker of the first hundreds of milliseconds of intentions processing probably related to
a contextual integrative mechanism and suggest its robustness by showing its blindness to task demands
manipulation.
