Death on the brain: effects of mortality salience on the neural correlates of ingroup and outgroup categorization

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.

An Ontological Framework to Facilitate Early Detection of 'Radicalization' (OFEDR)-A Three World Perspective

This paper presents an ontology that involves using information from various sources from different disciplines and combining it in order to predict whether a given person is in a radicalization process. The purpose of the ontology is to improve the early detection of radicalization in persons, thereby contributing to increasing the extent to which the unwanted escalation of radicalization processes can be prevented. The ontology combines findings related to existential anxiety that are related to political radicalization with well-known criminal profiles or radicalization findings. The software Protégé, delivered by the technical field at Stanford University, including the SPARQL tab, is used to develop and test the ontology. The testing, which involved five models, showed that the ontology could detect individuals according to "risk profiles" for subjects based on existential anxiety. SPARQL queries showed an average detection probability of 5% including only a risk population and 2% on a whole test population. Testing by using machine learning algorithms proved that inclusion of less than four variables in each model produced unreliable results. This suggest that the Ontology Framework to Facilitate Early Detection of 'Radicalization' (OFEDR) ontology risk model should consist of at least four variables to reach a certain level of reliability. Analysis shows that use of a probability based on an estimated risk of terrorism may produce a gap between the number of subjects who actually have early signs of radicalization and those found by using probability estimates for extremely rare events. It is reasoned that an ontology exists as a world three object in the real world.

Fighting death with health inequality: The role of mortality cognition and shifting racial demographics in policy attitudes

White Americans are predicted to soon comprise less than half of the U.S. population. Such demographic changes can affect political attitudes by threatening group status. The present studies built from this literature to examine a process in which information about such demographic shifts can also affect health policy attitudes, in part by increasing death-related thoughts, and that health inequalities may in turn buffer such cognitions. Three experiments ( N = 1,651) adopted a causal chain approach to test these ideas. In Study 1, exposure to demographic changes decreased support for equitable health policies. In Study 2, the demographic manipulation increased death-thought accessibility, unless paired with information about worsening health inequalities. In Study 3, contemplation of mortality lessened both support for equitable health policies and resources allocated to health equity. Health inequalities may mitigate existential concerns raised by shifting racial demographics.

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.

Visual cues of threat elicit greater steady-state electroencephalographic responses than visual reminders of death

Terror management theory (TMT) suggests that reminders of death activate an exclusive anxiety mechanism different from the one activated by other types of symbolic threats. This notion is supported by evidence showing how experimental participants verbally reflecting on their own death are then influenced in their opinions and behaviours. A previous study showed that magnitude of electroencephalography (EEG) activity is greater when images depicting death-related content are coupled with painful thermal stimuli compared to threat-related content. Here we expand on previous research by testing whether similar effects may be brought about by passive observation of generic visual reminders of death. More precisely, we hypothesised that fast periodic presentation of death-related vs. more generic threat-related images determine a preferential modulation of brain activity measured by means of EEG. In two experiments, we found that images depicting death content elicit lower frequency-tagged EEG response compared to more generic threat images. Visual evoked potentials revealed that a brief change of the scene from neutral to threat content elicits greater amplitude at the late latencies (compatible with a P300 potential), particularly at the parieto-occipital sites. Altogether, our findings suggest that, in a context where no reflection on death cues is allowed and no threatening stimuli in other modality occur, visual death cues trigger lower neural synchronisation than that elicited by similarly negative and arousing cues with divergent threatening meaning.

Reminders of Mortality Alter Pain-Evoked Potentials in a Chinese Sample

Pain is of evolutionary importance to human survival. However, the perception of pain could be changed when death-related thoughts are accessible. Although the influence of mortality salience (MS) on pain processing has been investigated in Westerners recently, it is unclear whether this effect is constrained by specific culture context since humans may employ cultural worldviews to defend the existence problem. The current study tested whether and how MS affected pain processing in a Chinese male sample. We primed participants with sentences indicating MS or negative affect (NA) on either of two days. Both before and after the priming, event-related potentials (ERPs) elicited by painful and non-painful electrical stimulations were recorded. Results showed that pain-evoked potentials were identified as an early negative complex N60-P90-N130 and a late positivity P260. Pain-evoked N130 after MS priming was larger than that after NA priming. Meanwhile, pain-evoked P260 decreased after MS priming but not after NA priming. These findings indicate that reminders of mortality affect both early sensory and late cognitive neural responses related to physical pain. Although previous studies reporting an increased effect of MS on perceived pain intensity in Westerners, we found an unchanged or possibly reduced effect in Chinese. Thus, the current work provides insight into a culture-sensitive perspective on how pain processing would be modulated when existential problem occurs.

The Last Word: A Comparison of Younger and Older Adults' Brain Responses to Reminders of Death

Objectives

Terror management theory (TMT) suggests increased death awareness motivates various human behaviors and defenses. Recent research reveals age differences in response to increased awareness of death, and older adults' proximity to death may contribute to these differences. In the first known investigation of attention's role in these age differences, we examined brain response associated with attention allocation for death-related stimuli.

Method

Younger (ages 18-28) and older (ages 61-78) adults viewed emotionally neutral, death-related negative, general negative, and positive words while recording event-related potentials (ERPs).

Results

Younger adults exhibited greater amplitudes in the late positive potential component of the ERP in response to death-related than negative words, whereas older adults showed the opposite pattern.

Discussion

Findings provide neurophysiological support for the shift in older adults' responses to death-related stimuli found in other TMT research as well as studies reporting reduced explicit death anxiety in older adults. Results also highlight the importance of considering stimuli content in studies of attention and emotion.

Gender and neural substrates subserving implicit processing of death-related linguistic cues

Our recent functional magnetic resonance imaging study revealed decreased activities in the anterior cingulate cortex (ACC) and bilateral insula for women during the implicit processing of death-related linguistic cues. Current work tested whether aforementioned activities are common for women and men and explored potential gender differences. We scanned twenty males while they performed a color-naming task on death-related, negative-valence, and neutral-valence words. Whole-brain analysis showed increased left frontal activity and decreased activities in the ACC and bilateral insula to death-related versus negative-valence words for both men and women. However, relative to women, men showed greater increased activity in the left middle frontal cortex and decreased activity in the right cerebellum to death-related versus negative-valence words. The results suggest, while implicit processing of death-related words is characterized with weakened sense of oneself for both women and men, men may recruit stronger cognitive regulation of emotion than women.

Distinct effects of reminding mortality and physical pain on the default-mode activity and activity underlying self-reflection

Behavioral research suggests that reminding both mortality and negative affect influences self-related thoughts. Using functional magnetic resonance imaging (MRI), we tested the hypothesis that reminders of mortality and physical pain decrease brain activity underlying self-related thoughts. Three groups of adults underwent priming procedures during which they answered questions pertaining to mortality, physical pain, or leisure time, respectively. Before and after priming, participants performed personality trait judgments on oneself or a celebrity, identified the font of words, or passively viewed a fixation. The default-mode activity and neural activity underlying self-reflection were identified by contrasting viewing a fixation vs. font judgment and trait judgments on oneself vs. a celebrity, respectively. The analyses of the pre-priming functional MRI (fMRI) data identified the default-mode activity in the posterior cingulate cortex (PCC), ventral medial prefrontal cortex (MPFC), and parahippocampal gyrus, and the activity underlying instructed self-reflection in both the ventral and dorsal regions of the MPFC. The analyses of the post-priming fMRI data revealed that, relative to leisure time priming, reminding mortality significantly reduced the default-mode PCC activity, and reminding physical pain significantly decreased the dorsal MPFC activity during instructed self-reflection. Our findings suggest distinct neural underpinnings of the effect of reminding morality and aversive emotion on default-mode and instructed self-reflection.

Attachment affects social information processing: Specific electrophysiological effects of maternal stimuli

Attachment is critical to each individual. It affects the cognitive-affective processing of social information. The present study examines how attachment affects the processing of social information, specifically maternal information. We assessed the behavioral and electrophysiological responses to maternal information (compared to non-specific others) in a Go/No-go Association Task (GNAT) with 22 participants. The results illustrated that attachment affected maternal information processing during three sequential stages of information processing. First, attachment affected visual perception, reflected by enhanced P100 and N170 elicited by maternal information as compared to others information. Second, compared to others, mother obtained more attentional resources, reflected by faster behavioral response to maternal information and larger P200 and P300. Finally, mother was evaluated positively, reflected by shorter P300 latency in a mother + good condition as compared to a mother + bad condition. These findings indicated that the processing of attachment-relevant information is neurologically differentiated from other types of social information from an early stage of perceptual processing to late high-level processing.

Thoughts of death modulate psychophysical and cortical responses to threatening stimuli

Existential social psychology studies show that awareness of one's eventual death profoundly influences human cognition and behaviour by inducing defensive reactions against end-of-life related anxiety. Much less is known about the impact of reminders of mortality on brain activity. Therefore we explored whether reminders of mortality influence subjective ratings of intensity and threat of auditory and painful thermal stimuli and the associated electroencephalographic activity. Moreover, we explored whether personality and demographics modulate psychophysical and neural changes related to mortality salience (MS). Following MS induction, a specific increase in ratings of intensity and threat was found for both nociceptive and auditory stimuli. While MS did not have any specific effect on nociceptive and auditory evoked potentials, larger amplitude of theta oscillatory activity related to thermal nociceptive activity was found after thoughts of death were induced. MS thus exerted a top-down modulation on theta electroencephalographic oscillatory amplitude, specifically for brain activity triggered by painful thermal stimuli. This effect was higher in participants reporting higher threat perception, suggesting that inducing a death-related mind-set may have an influence on body-defence related somatosensory representations.

Existential neuroscience: neurophysiological correlates of proximal defenses against death-related thoughts

A great deal of evidence suggests that reminders of mortality increase in-group support and worldview defense, presumably in order to deal with the potential for anxiety that roots in the knowledge that death is inevitable. Interestingly, these effects are obtained solely when thoughts of death are not in the focus of consciousness. When conscious, death-related thoughts are usually defended against using proximal defenses, which entail distraction or suppression. The present study aimed at demonstrating neurophysiological correlates of proximal defenses. We focused on the late positive potential (LPP), which is thought to reflect an increased allocation of attention toward, and processing of, motivationally relevant stimuli. Our prediction was that the LPP should be increased for death-related relative to death-unrelated, but equally unpleasant stimulus words. In Experiment 1, this prediction was confirmed. This finding was replicated in Experiment 2, which used a target word detection task. In Experiment 2, both death-related and pleasant words elicited an enhanced LPP, presumably because during the less demanding task, people might have distracted themselves from the mortality reminders by focusing on pleasant words. To summarize, we were able to identify a plausible neurophysiological marker of proximal defenses in the form of an increased LPP to death-related words.

Existential neuroscience: a functional magnetic resonance imaging investigation of neural responses to reminders of one's mortality

A considerable body of evidence derived from terror management theory indicates that the awareness of mortality represents a potent psychological threat engendering various forms of psychological defense. However, extant research has yet to examine the neurological correlates of cognitions about one's inevitable death. The present study thus investigated in 17 male participants patterns of neural activation elicited by mortality threat. To induce mortality threat, participants answered questions arranged in trial blocks that referred to fear of death and dying. In the control condition participants answered questions about fear of dental pain. Neural responses to mortality threat were greater than to pain threat in right amygdala, left rostral anterior cingulate cortex, and right caudate nucleus. We discuss implications of these findings for stimulating further research into the neurological correlates of managing existential fear.

Neurocognitive processes of linguistic cues related to death

Consciousness of the finiteness of one's personal existence influences human thoughts and behaviors tremendously. However, the neural substrates underlying the processing of death-related information remain unclear. The current study addressed this issue by scanning 20 female adults, using functional magnetic resonance imaging, in a modified Stroop task that required naming colors of death-related, negative-valence, and neutral-valence words. We found that, while both death-related and negative-valence words increased activity in the precuneus/posterior cingulate and lateral frontal cortex relative to neutral-valence words, the neural correlate of the processing of death-related words was characterized by decreased activity in bilateral insula relative to both negative-valence and neutral-valence words. Moreover, the decreased activity in the left insula correlated with subjective ratings of death relevance of death-related words and the decreased activity in the right insula correlated with subjective ratings of arousal induced by death-related words. Our fMRI findings suggest that, while both death-related and negative-valence words are associated with enhanced arousal and emotion regulation, the processing of linguistic cues related to death is associated with modulations of the activity in the insula that mediates neural representation of the sentient self.

The neural correlates of race

Behavioral analyses are a natural choice for understanding the wide-ranging behavioral consequences of racial stereotyping and prejudice. However, studies using neuroimaging and electrophysiological research have recently considered the neural mechanisms that underlie racial categorization and the activation and application of racial stereotypes and prejudice, revealing exciting new insights. Work that we review here points to the importance of neural structures previously associated with face processing, semantic knowledge activation, evaluation and self-regulatory behavioral control, enabling specification of a neural model of race processing. We show how research on the neural correlates of race can serve to link otherwise disparate lines of evidence on the neural underpinnings of a broad array of social-cognitive phenomena; we also consider the implications for effecting change in race relations.