Confirmation Bias among Adherents of Red and Yellow Politics in Thailand

Abstract

Thai politics has long been polarised between red and yellow ideologies. This study aims to explore bias among adherents of each political ideology. The study recruited 392 participants for an experiment. The participants were divided into 4 treatment groups based on the type of information that they were assigned to read. Principal component analysis was employed to identify the participants’ original political ideology and verify whether their original political beliefs changed or were maintained after exposure to the experimental information. The results of the RED+ treatment (exposure to positive information about red politics) revealed that participants on the red spectrum tended to confirm their original beliefs

after information exposure. However, participants on the yellow spectrum switched to the green spectrum (espousing neither red nor yellow ideologies). The results of the RED- treatment (exposure to negative information about red politics) demonstrated confirmation bias among the participants. The participants who held red and yellow ideologies intensified their political beliefs. The results of the YELLOW+ treatment (exposure to positive information about yellow politics) suggested that the political conviction of participants on the red spectrum decreased, and some participants on the yellow spectrum switched to the red spectrum. The results of YELLOW- treatment (exposure to negative information about yellow politics) revealed that the number of participants on the red spectrum decreased, even though the information supported their beliefs. These results implied that confirmation bias in politics still exists. However, the decrease in political convictions after some treatments suggested that participants still held some sympathy for political opposition groups.