The Effect Of Models And Potential Mate Attractiveness On Female Mate Choice Copying

Starting from Darwin's theory of sexual selection,a key issue in evolutionary biology is how sexual organisms chose their mate,especially for females.Numerous cross-species studies have shown that individuals may not only rely on the independent mate choice strategy based on genetic preference,but can also generate a nonindependent strategy by learning others' mate choice.This phenomenon is called mate choice copying.Mate choice copying refers to that individuals obtain social information about potential mate by observing the interactions of same-sex model and potential mate which related to sexual selection and then with acquired social information to evaluate and select their partners.When using social information to make a mate choice decision,individuals are able to learn both the positive and negative attitudes expressed by models towards potential mates,with representing the two kind of copying strategies.Research points out that mate choice copying helps individuals to reduce the time and effort required to select their best mate,and it also helps reducing the costs and risks caused by an inaccurate mate choice.More importantly,mate choice copying can guide the cultural inheritance of mate preferences,influencing the direction and proportion of sexual selection and hence the evolution in the development of population.Previous studies have examined the existence of mate choice copying in different species and have initially explored the factors affecting the mate choice copying effect.Exploring the occurrence and variation of mate choice copying under different factors will provide a clearer and more comprehensive picture of the important role of this phenomenon in social behavior and sexual selection.Mate choice copying is defined as a form of social learning,specifically the learning of social information about potential mates from models,and therefore when exploring the factors that influence the mate choice copying effect,social information from model cues should be taken into consideration.Furthermore,as mate choice copying is a non-independent strategy that influences individual mate choice together with the independent strategy of genetic preference,it is worth exploring whether factors related to individual genetic preference may also influence mate choice copying behavior based on social information learning.Previous research has suggested that the number of models associated with model cues may be an important extrinsic factor in mate choice copying behavior,however,this issue has not been explored in depth.Moreover,in other field of social learning,it has been found that whether the observer-observed relationship is in-group or out-group has an impact on an individual's social learning,however,it still remains unclear whether this factor also plays a role in mate choice copying behavior.Among the factors associated with individual preferences,the level of attractiveness of potential mates influences individuals' genetic preference-based mate choice directly,and it remains to be seen whether this factor also influences social information based learning of mate choice copying,i.e.whether social learning of mate choice copying can be influenced by social cues while also integrating the influence of genetic preference-based factors of potential mate attractiveness.Therefore,based on the two copying strategies of positive attitude copying and negative attitude copying,this series of studies aims to investigate the influence of social information factors from model cues and individual genetic preference factors on female mate choice copying behavior by manipulating the number of models,ingroup and out-group models and the level of attractiveness of potential mates.By using functional MRI,we explore the brain activities involved in female mate choice copying and the changes of brain activities of the mate choice copying under different factors in order to further expand the field of female mate choice copying.The present research included three studies with a total of six experiments.Study 1(experiment 1 and experiment 2)investigated the effects of the number of models on female mate choice copying behavior and related brain activities separately through behavior experiment and fMRI experiment.Study 2(experiment 3 and experiment 4)investigated the effects of in-group and out-group models on female mate choice copying behavior and related brain activities respectively through behavior experiment and fMRI experiment.Study3(experiment 5 and experiment 6)investigated the effects of potential mates' attractiveness on female mate choice copying behavior and related brain activities separately through behavior experiment and fMRI experiment.The results of study 1 found that the subjects had significantly mate choice copying behaviors that the second and first scores of the female subjects on the willingness to choose the male as a boyfriend reached a statistically significant level after observing the attitude of the model to the potential mate which revealed that both the positive attitude and the negative attitude of the model were copied.Further,the effect of model number on female mate choice copying occurs only under the condition of positive attitude of model towards potential mate.The fMRI results showed that the dorsomedial prefrontal cortex(DMPFC)was involved in the occurrence of female mate choice copying;when copying the positive attitude of models towards potential mate made dorsomedial prefrontal cortex and inferior frontal gyrus(IFG)involved more than the negative attitude of role models.Further,when copying the positive attitude the activation of middle cingulate gyrus(MCC)was significantly different from the number of models.The study 2 found that the subjects had significantly mate choice copying behaviors after observing the attitude of the role model to the potential mate which not only copied of the positive attitude of the model,but also copied of the negative attitude of the model.Further,the influence of in-group and out-group models on female mate choice copying only occurs under the condition of positive attitude of models to potential mates.The fMRI results showed that the DMPFC was involved in the occurrence of female mate choice copying;when copying the positive attitude of models towards potential mate made DMPFC and IFG involved more than that of negative attitude towards models.Further,copying the positive attitude the activation of MCC was significantly different from that of in-group and out-group models.The study 3 found that the subjects had significantly mate choice copying behaviors after observing the attitude of the model to the potential mate which not only copied the positive attitude of the model,but also copied the negative attitude of the model.Further,the effect of high and low attractiveness level on female mate choice copying only occurs under the condition of negative attitude of role model to potential mate.The fMRI results also found that the DMPFC was involved in the occurrence of female mate choice copying;when copying the positive attitude of models towards potential mate made DMPFC and IFG involved more than that of negative attitude towards models;Further,when copying the negative attitude of the models,the activation of MCC was significantly different from that of potential mate attractiveness.In summary,this series of studies examined the effects of the number of models,in-group and out-group models and the level of potential mate attractiveness on female mate choice copying from behavioral and fMRI experiments.Overall,the female mate choice copying effect was demonstrated at the behavioral level,with both positive and negative copying being stable,with female subjects demonstrating positive copying when models expressed positive attitudes towards potential mates and negative copying when models expressed negative attitudes towards potential mates,which is consistent with previous research.This study further suggested that the number of models,ingroup and out-group models and the attractiveness level of potential mates had an effect on female mate choice copying,with the number of models and in-group and out-group models mainly affecting mate choice copying under positive attitudes,specifically the positive copying effect was significantly stronger when there were more models than when there were fewer models,and the positive copying effect was significantly stronger when there were in-group models than when there were out-group models.The level of attractiveness of potential mates mainly influenced the copying of negative attitudes,specifically,the negative copying effect was significantly stronger in subjects with highly attractive potential mates than with less attractive potential mates.The fMRI results suggested that the DMPFC activate strongly during the copying of mate choice.The DMPFC and IFG activated stronger during the copying of positive attitudes of models compared to the copying of negative attitudes of the models significantly.The number of models,in-group and out-group models and potential mate attractiveness level on brain activity of mate choice copying were all found to change with extrinsic factors,with the number of models and in-group and out-group models mainly influencing the activation of the MCC.The number of models and in-group and out-group models mainly influence the activation of the middle cingulate gyrus in positive attitudes and the level of potential mate attractiveness mainly influencing the activation of the middle cingulate gyrus in negative attitudes.This series of studies provides additional empirical evidence for understanding female mate choice copying behavior at both behavior and brain levels.