The Survival Processing Advantage Of Facial Trustworthiness: Social Identity Perspective

Face, as a kind of important resource which represents individual character,behavior, and the social group membership information, can provide abundant socialinformation. Face can represent an individual’s claimed sense of positive image in thecontext of social interaction when encountering with a stranger and face also affectsthe formation of impression. Face plays a vital role in the course of characterizing thesocial intentions. The inference of trait (eg: trustworthiness) from the face oftendetermines the process of social interaction in advance. Facial trustworthiness refersto a kind of the subjectively estimated degree of one’s trustworthiness from theperson’s facial information. Face could provide the potential information about thetrustworthiness and untrustworthiness of others and decide whether an individualshould be taken to avoid or approach in this estimation, and the detection is related tothe survival of humanity.With the importance of facial trustworthiness was confirmed by extensiveliteratures in the social perception and social behavior area, the studies have shownthat the face exposed within100ms was judged very quickly, and the facialtrustworthiness could be perceived by people. This judgment is automatic and withoutconscious effort. Scholars believe that the reason why people can judge manycharacters of the facial trustworthiness from the facial information so quickly may berelated to a wide range of evolutionary background. The evolutionary significance ofthe facial trustworthiness was supported by overgeneralization of emotion hypothesisand the fraud detection module of social contract theory. Facial trustworthiness issuehas become a new topic which is worth of concerning in the evolutionary psychology.Early this century, psychologists found the phenomenon of survival processing advantage existed in the field of memory when they examined the adaptive functionof memory. This survival processing effect also became an effective method whichproved the evolutionary significance of mental phenomena. The processing effectaims to speculate the memory when the survival situation is compared to thecontrolling group of words and images and other stimulus by recalling andrecognition of the dependent variable. The phenomenon of survival processingadvantage of memory has been confirmed within a variety of control conditions (suchas removal, collection contests, etc.) and various stimulus materials (such as pictures,words, etc.). But there are still scholars who find that there is no difference of facememorization when the survival processing is compared to the control condition bythe way of taking the real face and3D face as the stimulus materials. However, thefindings are not consistent with the vast documentary results and inferences of theadaptive function of memory. Based on this question, how to confirm the evolutionarysignificance of the face in the laboratory is our first concerning purpose.From the evolutionary psychology point of view, individual memory is effectedby lots of factors, one of which is the valence of the emotion or the arousal of theevents. Compared to neutral events, the event of emotional arousal is more concernedby adults who could also produce better memory. Some scholars suggest that negativeevents are more adaptive than the positive events in the adaptation because thenegative event transits the signals of potential threat and harm, which adjusts thembetter to avoid harm for surviving and leads to the negative bias of memory. From thisinference, this kind of negative bias for the distrust face means a threat which willlead to the appearance of survival processing advantages. Based on this, this study putforwards that the survival processing advantage of facial memory may perform on thedistrust faces. This assumption is verified on experiment1.The study chose a total of144trust, neutral and distrust faces as the stimulusmaterials based on self-built trust database. We examined the survival processing advantage of the3D face (experiment1) and the real face (experiment2) for theabove hypothesis. Two studies consistently showed that the recall performance onsurvival processing condition for distrust face is significant higher than that of controlprocessing condition, and it confirmed there was survival processing advantage ondistrust face. Meanwhile, the research showed that there was still survival processingadvantage on distrust face under the condition of high confidence, which means thedistrust face has good quality on memory. This result is consistent with the negativebias hypothesis. The evolutionary psychology shows that all the information is notequal processed in the memory system which is a kind of adaptive psychologicalfunction. Only the information that is vital for human survival can enter memorysystem, and the attention to negative information can play a moderate effect onsurvival crisis of organism, which will increase the possibility of its delivery from thememory and improve the fitness of individuals.In addition, the theory of evolution regards the human as a group living species,and many aspects of human psychology evolution are based on group as the center.Therefore, our study also explores the survival processing advantage of facialtrustworthiness on the group level. Based on the minimal group method of socialcategory, we divide the participants into ingroup and outgroup by classical dotestimation in experiment3. The results showed that this optional division can alsoimpact on memorization effect of facial trustworthiness which showed that facicalmemorization effect of ingroup is significantly superior to that of outgroup.Furthermore, the results showed that the trustworthy facial memorization of ingroupunder the survival condition was significantly better than that under the controlcondition. It is confirmed on the group level that there is the memorization ofprocessing advantages toward ingroup trustworthy faces. As a group living species,only cooperate with ingroup members can people be more conducive to the survivaldevelopment of the group. The trustworthy face reflects a tendency of cooperation and reciprocity with others on group level. The good memory performance on ingrouptrustworthy face is beneficial to the cooperation and reciprocity of ingroup members,which is in accordance with group evolutionary logic. Therefore the survivalprocessing advantage of ingroup trustworthiness face is a typical representation as oneadaptive function in memory system. Meanwhile, we also found there is also asignificant survival processing advantage on untrustworthy face of ingroup undersocial category condition, which may be related to the individual’s instinct belongingand security not sufficiently achieved under this condition.McLeish and Oxoby (2011) essay writing priming technique was used inExperiment4, which aimed to manipulate the social identity level. Compared to theresult which survival processing advantage showed on both trustworthy face anduntrustworthy face under the control condition, however, under the identity primingcondition, we found the survival processing advantage existed on trustworthy faceonly and the strength of the advantage in this condition was superior to that in controlcondition. This result deepens the finding of experiment3and shows that with theincrease of identity strength, the survival processing advantage of trustworthy facewill be more reinforced, but decreased on untrustworthy face, and this phenomenonwhich stresses the cooperation and reciprocals is more in line with the direction of theevolution on the group level.In conclusion, based on the research of minimal group paradigm, our studyconfirms preliminarily that social category and social identity, as two levels of socialidentity theory, are the variation conditions of survival processing advantage of facialtrustworthiness change respectively on the group level.