| Previous studies have shown that the human’s perception of surrounding environment is not always accurate.Instead,they have cognitive and behavioral bias.Gaze is an important social cue for human’s communication.However,current studies that are related to gaze mainly focus on the self-related bias and visual field bias.Whether there exists a leftward perception bias of gaze direction has not been investigated.To address this gap,we conducted two studies to investigate the possible gaze perception bias and the influence that emotion has on it.We also study the correlation between brain lateralization and emotion-induced gaze perception bias.Study 1: four behavioral experiments were conducted using a forced-choice gaze direction judgment task.The face stimuli included four expression and ten standard unit gaze directions.The point of subjective equality(PSE)was employed to measure whether there was a leftward perception bias of gaze direction,and if there was,whether this bias was modulated by face emotion.The results showed that the PSE of fearful faces was significantly positive as compared to zero and this effect was not found in angry,happy,and neutral faces,indicating that participants were more likely to judge the gaze direction of fearful faces as directed to their left-side space,namely a leftward perception bias.Study 2: we used Pearson correlation analysis to investigate whether gaze direction perception bias was correlated with alpha asymmetry(AA)that recorded in frontal,occipital and occipital-temporal regions and whether such correlation was modulated by emotional expression.According to the AA score,we divided the participants into three groups: all participants group,AA < 0 group and AA > 0 group.The results revealed that: For all the participants group,the only positive relationship was found between AA and gaze perception bias of angry face in occipital region,while no other relations were found in other conditions;For AA < 0 group,there were significant or marginally significant positive relations between AA and gaze perception bias of fearful,angry and neutral emotion in frontal region.Besides,the only correlation in occipital area was found when subjects judge the direction of angry faces,while there was negative relationship between AA and fearful-modulated gaze perception bias in posterior occipital(temporal-occipital region).Overall,our study demonstrates that there is a perception bias of gaze direction,and the bias is modulated by emotion in face.Such emotion-modulated leftward gaze perception bias is also correlated with the cerebral lateralization in humans. |
