The Black And White Metaphor Of Moral Concepts And Its Neural Mechanisms

Metaphor is a mapping relationship between concrete,tangible concepts,and abstract,intangible concepts.Abstract concepts are often understood and expressed through metaphors.Exploring the mechanism of metaphor helps us understand the influence of perception on advanced social cognitive processing.It has been found that both in Chinese and foreign cultures,black and white color and moral concepts have a specific metaphorical connection,that is,"black-immoral"and "white-moral" metaphors.However,the metaphorical connection is not stable in different color carriers and moral materials.Therefore,the first purpose of this study is to explore the effect of moral black-and-white metaphors in different color carriers and moral materials.At present,most of the research on moral black-and-white metaphor focuses on behavior,and the discussion of its neural mechanism is not enough.According to the theory of embodied cognition,perception and motor systems are the neural basis of metaphor.A study using non-invasive brain stimulation technology confirmed that both the occipital lobe(involved in visual processing)and the prefrontal lobe(involved in the processing of abstract moral concepts)played a key role in moral black-and-white metaphors.However,this study only confirmed that the two brain regions were important and could not examine the association between them.Therefore,the second purpose of this study is to explore the relevant brain regions and their connections in moral black-and-white metaphors at the level of neural mechanisms.This study consists of three experiments from two studies.Study 1 aims to examine the effects of moral black-and-white metaphor in different situations,including two experiments.Experiment 1 uses the moral Stroop task to examine the black-and-white metaphor effect between moral words and word colors,and Experiment 2 also uses the moral Stroop task to examine the black-and-white metaphorical effects between the background color and the sketch of the moral situation.Study 2(Experiment 3)combines the functional magnetic resonance imaging(fMRI)technology,psychophysiological interaction(PPI)analysis,and other methods,to examine the relevant brain regions of the moral black-and-white metaphor and the functional connectivity between them.The results of Study 1 showed that the interaction between word color and word type is significant in the task of moral vocabulary judgement.The black moral Stroop effect(the difference between the reaction of immoral words and the reaction of moral words)is significantly smaller than the white moral Stroop effect,indicating that there is a moral black-and-white metaphor effect between moral words and word colors.While in the task of moral sketch judgement,the interaction between the background color and sketch type is not significant,which indicates that there is no moral black-and-white metaphor effect between moral sketch and background color.The results of Study 2 find that at the behavioral level,the interaction between color and word types is significant,indicating the existence of a moral black-and-white metaphorical effect.The whole-brain activation analysis finds that the fusiform gyrus and its surrounding brain regions have greater activation under white conditions than under black conditions.There is greater activation of the medial superior frontal gyrus,the glossal gyrus,and the inferior occipital gyrus under the immoral condition than under the moral condition.In PPI analysis,functional connectivity between the visual area responsible for visual information processing and the supplementary motor area(SMA)for conflict processing is enhanced when processing "black-moral" information and "white-immoral" information(metaphorically incongruent information),compared to "black-immoral" information and "white-moral" information(metaphorically congruent information).The intensity and behavioral metaphorical conflict of functional connectivity are significantly positively correlated.The results show that in the process of processing moral black-and-white metaphor,color information influenced advanced moral processing by influencing the functional connectivity between the visual brain region and cognitive control region.When metaphor is incongruent,the functional connectivity between the visual and cognitive control brain region is strong,and when the metaphor is congruent,the functional connectivity between the visual area and cognitive control brain region is weak.The findings of this study show that some forms of moral concepts can be represented by black and white colors,and that color metaphors can influence the processing of this part of moral concepts.What’s more,this study reveals for the first time the brain activation and brain functional connectivity in the process of moral black-and-white metaphor processing,which provides the evidence support at the neural mechanism level for the theory of embodied cognition,that is,the perception and motor systems are the neural basis of metaphor.At the same time,this study also provides new evidence for the neural mechanism of moral processing and conceptual metaphor.