Brain imaging under group pressure using the Asch experiment: An fNIRS study

Abstract

In this study, we investigated brain activity under social pressure using Solomon Asch's experimental paradigm. We replicated the group situation using the MORI technique and recorded the brain activity using functional near-infrared spectroscopy (fNIRS). Eight Japanese healthy males in groups of four participated in this study. The Asch experiment can be replicated without using confederates using MORI technique. The subject assessed with fNIRS was seated in a fixed position and assigned to answer third. A multichannel fNIRS system was used to measure the changes in the concentrations of oxy-hemoglobin (oxy-Hb) and deoxy-hemoglobin (deoxy-Hb). Nine optodes consisting of 12 channels were placed over the prefrontal cortex (PFC) of each hemisphere. In the behavioral data, the error rate (%) for the judgment tasks increased to 39.7% under the group pressure conditions, while it was 3.2% under the control conditions. Comparing the group pressure and control conditions in the fNIRS data, a difference in the increasing rate of oxy-Hb in the frontal pole (ch02, 05, 13 & 15) was observed. Therefore, we found that the frontal pole was activated when the subject felt social pressure under group situations.View full abstract