Perspective-Taking in Sentence Comprehension: Time and Empathy

Time course of effective connectivity associated with perspective taking in utterance comprehension

This study discusses the effective connectivity in the brain and its time course in realizing perspective taking in verbal communication through electroencephalogram (EEG) associated with the understanding of Japanese utterances. We manipulated perspective taking in a sentence with the Japanese subsidiary verbs -ageru and -kureru, which mean "to give". We measured the EEG during the auditory presentation of the sentences with a multichannel electroencephalograph, and the partial directed coherence and its temporal variations were analyzed using the source localization method to examine causal interactions between nineteen regions of interest in the brain. Three different processing stages were recognized on the basis of the connectivity hubs, direction of information flow, increase or decrease in flow, and temporal variation. We suggest that perspective taking in speech comprehension is realized by interactions between the mentalizing network, mirror neuron network, and executive control network. Furthermore, we found that individual differences in the sociality of typically developing adult speakers were systematically related to effective connectivity. In particular, attention switching was deeply concerned with perspective taking in real time, and the precuneus played a crucial role in implementing individual differences.

Different Neural Responses for Unfinished Sentence as a Conventional Indirect Refusal Between Native and Non-native Speakers: An Event-Related Potential Study

Refusal is considered a face-threatening act (FTA), since it contradicts the inviter’s expectations. In the case of Japanese, native speakers (NS) are known to prefer to leave sentences unfinished for a conventional indirect refusal. Successful comprehension of this indirect refusal depends on whether the addressee is fully conventionalized to the preference for syntactic unfinishedness so that they can identify the true intention of the refusal. Then, non-native speakers (NNS) who are not fully accustomed to the convention may be confused by the indirect style. In the present study, we used event-related potentials (ERPs) of electroencephalography in an attempt to differentiate the neural substrates for perceiving unfinished sentences in a conventionalized indirect refusal as an FTA between NS and NNS, in terms of the unfinishedness and indirectness of the critical sentence. In addition, we examined the effects of individual differences in mentalization, or the theory of mind, which refers to the ability to infer the mental states of others. We found several different ERP effects for these refusals between NS and NNS. NNS induced stronger P600 effects for the unfinishedness of the refusal sentences, suggesting their perceived syntactic anomaly. This was not evoked in NS. NNS also revealed the effects of N400 and P300 for the indirectness of refusal sentences, which can be interpreted as their increased processing load for pragmatic processing in the inexperienced contextual flow. We further found that the NNS’s individual mentalizing ability correlates with the effect of N400 mentioned above, indicating that lower mentalizers evoke higher N400 for indirect refusal. NS, on the contrary, did not yield these effects reflecting the increased pragmatic processing load. Instead, they evoked earlier ERPs of early posterior negativity (EPN) and P200, both of which are known as indices of emotional processing, for finished sentences of refusal than for unfinished ones. We interpreted these effects as a NS’s dispreference for finished sentences to realize an FTA, given that unfinished sentences are considered more polite and more conventionalized in Japanese social encounters. Overall, these findings provide evidence that a syntactic anomaly inherent in a cultural convention as well as individual mentalizing ability plays an important role in understanding an indirect speech act of face-threatening refusal.

An EEG Analysis of Honorification in Japanese: Human Hierarchical Relationships Coded in Language

This study examines the neural substrate of the understanding of human relationships in verbal communication with Japanese honorific sentences as experimental materials. We manipulated two types of Japanese verbs specifically used to represent respect for others, i.e., exalted and humble verbs, which represent respect for the person in the subject and the person in the object, respectively. We visually presented appropriate and anomalous sentences containing the two types of verbs and analyzed the electroencephalogram elicited by the verbs. We observed significant parietal negativity at a latency of approximately 400 ms for anomalous verbs compared with appropriate verbs. This parietal negativity could be a manifestation of the pragmatic process used to integrate the linguistic forms with the human relationships represented in the sentences. The topographies of these event-related potentials (ERPs) corresponded well with those of ERPs for two second-person pronouns in Chinese (plain ni and respectful nin). This correspondence suggests that the pragmatic integration process in honorific expressions is cross-linguistically common in part. Furthermore, we assessed the source localization by means of independent component (IC) analysis and dipole fitting and observed a significant difference in ERP between the honorific and control sentences in the IC cluster centered in the precentral gyrus and in the cluster centered in the medial part of the occipital lobe, which corresponded well with the functional magnetic resonance imaging findings for Japanese honorification. We also found several significant differences in the time-frequency analyses for the medial occipital cluster. These significant differences in the medial occipital cluster suggested that the circuit of the theory of mind was involved in the processing of Japanese honorification. Our results suggest that pragmatic and syntactic processing are performed in parallel because the person to be respected must fulfill the grammatical function appropriate for the honorific verb.