Neural responses to one's own name under mortality threat

Specificity in the processing of a subject's own name

Subject's own name (SON) is widely used in both daily life and the clinic. Event-related potential (ERP)-based studies have previously detected several ERP components related to SON processing; however, as most of these studies used SON as a deviant stimulus, it was not possible to determine whether these components were SON-specific. To identify SON-specific ERP components, we adopted a passive listening task with EEG data recording involving 25 subjects. The auditory stimuli were a SON, a friend's name (FN), an unfamiliar name (UN) selected from other subjects' names and seven different unfamiliar names (DUNs). The experimental settings included Equal-probabilistic, Frequent-SON, Frequent-FN and Frequent-UN conditions. The results showed that SON consistently evoked a frontocentral SON-related negativity (SRN) within 210-350 ms under all conditions, which was not detected with the other names. Meanwhile, a late positive potential evoked by SON was found to be affected by stimulus probability, showing no significant difference between the SON and the other names in the Frequent-SON condition, or between the SON and a FN in the Frequent-UN condition. Taken together, our findings indicated that the SRN was a SON-specific ERP component, suggesting that distinct neural mechanism underly the processing of a SON.

Reminders of Mortality: Investigating the Effects of Different Mortality Saliences on Somatosensory Neural Activity

The Terror Management Theory (TMT) offered a great deal of generative hypotheses that have been tested in a plethora of studies. However, there is a still substantive lack of clarity about the interpretation of TMT-driven effects and their underlying neurological mechanisms. Here, we aimed to expand upon previous research by introducing two novel methodological manipulations aimed to enhance the effects of mortality salience (MS). We presented participants with the idea of the participants' romantic partner's death as well as increased the perceived threat of somatosensory stimuli. Linear mixed modelling disclosed the greater effects of MS directed at one's romantic partner on pain perception (as opposed to the participant's own mortality). The theta event-related oscillatory activity measured at the vertex of the scalp was significantly lower compared to the control condition. We suggest that MS aimed at one's romantic partner can result in increased effects on perceptual experience; however, the underlying neural activities are not reflected by a classical measure of cortical arousal.

Religious Afterlife Beliefs Decrease Behavioral Avoidance of Symbols of Mortality

An astonishing cultural phenomenon is where, far away from or close to a city center, people in different societies localize cemeteries that function as both sites of memory of lost ones and symbols of mortality. Yet a psychological account of such differences in behavioral responses to symbols of mortality is lacking. Across five studies (N = 1,590), we tested a psychological model that religious afterlife beliefs decrease behavioral avoidance of symbols of mortality (BASM) by developing and validating a word-position task for quantifying BASM. We showed evidence that religious believers, including Christians, Muslims, Hindus, and Buddhists, exhibited decreased BASM relative to nonbelievers. We also provide evidence for a causal relationship between religious afterlife beliefs and reduced BASM. Our findings provide new insight into the functional role of religious afterlife beliefs in modulating human avoidance behavior in response to symbols of mortality.

Distinct Effects of Stimulus Repetition on Various Temporal Stages of Subject's Own Name Processing

The self is one of the most important concepts in psychology, which is of great significance for human survival and development. As an important self-related stimulus, the subject’s own name (SON) shows great advantages in cognitive and social processing and is widely used as an oddball stimulus in previous studies. However, it remained unknown whether the multiple repetition of stimulus would have similar influence on the neural response to SON and the other names under equal probability. In this study, adopting EEG and an equal–probability paradigm, we first detected the SON-related ERP components which could differentiate SON from other names, and then investigated how these components are influenced by repeated exposure of the stimulus. Our results showed that SON evoked an earlier SON-related negativity (SRN) at the fronto-central region and a late positive potential (LPP) at the centro-parietal region. More intriguingly, the earlier SRN demonstrated reduction after multiple repetitions, whereas LPP did not exhibit significant changes. In conclusion, these findings revealed that multiple repetitions of the stimulus might influence the various temporal stages in SON-related processing and highlighted the robustness of the late stage in this processing.

Mortality threat mitigates interpersonal competition: an EEG-based hyperscanning study

Awareness of death has been shown to influence human cognition and behavior. Yet, how mortality threat (MT) impacts our daily social behavior remains elusive. To address this issue, we developed a dyadic experimental model and recruited 86 adults (43 dyads) to complete two computer-based tasks (i.e. competitive and cooperative button-pressing). We manipulated dyads’ awareness of death [MT vs neutral control (NC)] and simultaneously measured their neurophysiological activity using electroencephalography during the task. Several fundamental observations were made. First, the MT group showed significantly attenuated competition and slightly promoted cooperation. Second, compared to NC, MT significantly decreased gamma-band inter-brain synchronization (IBS) in the competitive context, which was associated with increased subjective fear of death within dyads. Notably, those effects were context-specific: we did not observe comparable results in the cooperative context. Finally, a machine-learning approach was successfully used to discriminate between the MT and NC groups based on accumulated IBS. Together, these findings indicate that MT to some extent mitigates interpersonal competition, and such mitigation might be associated with changes in gamma-band IBS.

Brain Activation during Thoughts of One's Own Death and Its Linear and Curvilinear Correlations with Fear of Death in Elderly Individuals: An fMRI Study

Facing one's own death and managing the fear of death are important existential issues, particularly in older populations. Although recent functional magnetic resonance imaging (fMRI) studies have investigated brain responses to death-related stimuli, none has examined whether this brain activation was specific to one's own death or how it was related to dispositional fear of death. In this study, during fMRI, 34 elderly participants (aged, 60-72 years) were presented with either death-related or death-unrelated negative words and asked to evaluate the relevance of these words to the "self" or the "other." The results showed that only the left supplementary motor area (SMA) was selectively activated during self-relevant judgments of death-related words. Regression analyses of the effect of fear of death on brain activation during death-related thoughts identified a significant negative linear correlation in the right supramarginal gyrus (SMG) and an inverted-U-shaped correlation in the posterior cingulate cortex (PCC) only during self-relevant judgments. Our results suggest potential involvement of the SMA in the existential aspect of thoughts of death. The distinct fear-of-death-dependent responses in the SMG and PCC may reflect fear-associated distancing of the physical self and the processing of death-related thoughts as a self-relevant future agenda, respectively.

Self-esteem and cultural worldview buffer mortality salience effects on responses to self-face: Distinct neural mediators

Terror management theory proposes cultural worldview and self-esteem as two buffers against death anxiety. The neural mediators of these buffering effects, however, have not been fully understood. The present work investigated neural mediation mechanisms between self-esteem/cultural trait (self-construal) and mortality salience (MS) effects on self-face processing. We found that MS (vs. NA) priming eliminated self-face advantage in behavioral judgments of face-orientation in low self-esteem individuals and reduced self-face advantage in behavioral judgments of facial-familiarity in individuals with high interdependent self-construals. Our functional magnetic resonance imaging (fMRI) results showed that, following MS priming, insular activities mediated the relationship between self-esteem and self-face advantage in face-orientation judgments, whereas dorsal medial prefrontal activity mediated the relationship between interdependent self-construal and self-face advantage in face-familiarity judgments. Our findings suggest that distinct neural mechanisms are engaged in mediating the relationships between self-esteem/cultural trait and MS effects on the emotional and cognitive processes of self-relevant information.

The influence of self-referential stimuli on duration perception

Previous studies have shown that stimuli with subjective salience could affect duration estimation. Although self-referential stimuli possess high biological and social importance, no prior study has examined whether and how self-referential information affects duration perception. Experiment 1 used the temporal bisection task to investigate participants' duration estimation of the presentation of their own name versus familiar and unfamiliar names. The results showed that participants overestimated the duration of their own name and became more sensitive to duration perception in such trials when compared with stranger's names. Given the specificity of personal name, Experiment 2 used two types of personality-trait words in self-referential and friend-referential manner as the targets of duration perception. The duration of self-referential negative trait words was perceived to be longer relative to friend-referential negative trait words. The mechanism underlying the subjective time dilation effect of self-referential information possibly involves the engagement of increased attentional resources, which could allow the individual to preserve a certain level of stability and positivity of self-knowledge.

Prediction-based neural mechanisms for shielding the self from existential threat

The human mind has an automatic tendency to avoid awareness of its mortality. How this protective mechanism is implemented at the neuronal level is unknown. Here we test the hypothesis that prediction-based mechanisms mediate death-denial by shielding the self from existential threat. We provide evidence that self-specific predictive processes are downregulated during the perception of death-related linguistic stimuli and that this mechanism can predict fear-of-death. Using a magnetoencephalography visual mismatch paradigm, we show that the brain's automatic prediction response to deviancy is eliminated when death words and self-face representations are coupled, but remains present when coupled to other-face or to negative words. We further demonstrate a functional link between how death impacts self-image vs. Other-image, and show that it predicts fear-of-death. Finally, we confirm this effect in a behavioral active inference experiment showing that death-related words bias perceptual judgment on facial self and other morphed video clips. Together these results lay out, for the first time, a plausible neural-based mechanism of death-denial.