Finding indexes of spontaneous brain-to-brain communications when looking for a cause of the similarity of qualia assumed across individuals

Abstract

Qualia, the individual instances of subjective conscious experience, are private events. However, in everyday life, we assume qualia of others and their perceptual worlds, to be similar to ours. One way this similarity is possible is if qualia of others somehow contribute to the production of qualia by our own brain and vice versa. To test this hypothesis, we focused on the mean voltages of event-related potentials (ERPs) in the time-window of the P600 component, whose amplitude correlates positively with conscious awareness. These ERPs were elicited by images of the international affective picture system in 16 pairs of friends, siblings or couples going side by side through hyperscanning without having to interact. Each of the 32 members of these 16 pairs faced one half of the screen and could not see what the other member was presented with on the other half. One stimulus occurred on each half simultaneously. The sameness of these stimulus pairs was manipulated as well as the participants’ belief in that sameness by telling subjects’ pairs that they were going to be presented with the same stimuli in two blocks and with different ones in the two others. ERPs were more positive at all electrode subsets for stimulus pairs that were inconsistent with the belief than for those that were consistent. In the N400 time window, at frontal electrode sites, ERPs were again more positive for inconsistent than for consistent stimuli. As participants had no way to see the stimulus their partner was presented with and thus no way to detect inconsistence, these data might reveal an impact of the qualia of a person on the brain activity of another. Such impact could provide a research avenue when trying to explain the similarity of qualia across individuals.

Effects of Stimulus Processing on Event-Related Brain Potentials of Close Others

“…The partner could have processed these reactions given that the two subjects of each pair were not visually isolated. Despite the absence of conscious detection of stimulus inconsistency revealed by the debriefing session, there could have been a covert detection, which could have generated the consistency effect on ERPs reported in Bouten et al (2015). The first experiment of the present study was thus done to see if their results could be replicated when subjects cannot see each other.…”

“…As mentioned, in Bouten et al (2015), some (i.e., about 15%) of the IAPS images used as stimuli were quite emotionally laden. Therefore, they might have triggered subtle body movements or postural reactions from participants.…”

“…Most importantly, they could neither see the stimuli simultaneously presented to their partners nor their reactions to them. As in Bouten et al (2015), around 400 ms after the onset of the stimuli, ERPs started being more positive in inconsistent conditions. Namely, when the two subjects of each pair were presented with the same stimulus whereas they were told it would be a different one and vice-versa (i.e., different-stimuli expected to be same).…”

“…New pairs of closely related people were recruited and the same procedure as that of Bouten et al (2015) was used.…”

“…In an attempt to search for such an impact of perception on others, Bouten et al's (2015) recorded the electroencephalogram (EEG) of persons who were sitting next to a subject to whom stimuli were presented. These persons could not see the stimuli presented to the subject, as the aim was to see whether the perceptual stimulus created by the subject in response to this presentation had an impact on the activity of the brain of that other person.…”