Existential neuroscience: neurophysiological correlates of proximal defenses against death-related thoughts - PubMed (original) (raw)

Johannes Klackl et al. Soc Cogn Affect Neurosci. 2013 Mar.

Abstract

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.

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Figures

Fig. 1

Fig. 1

Summary of the ERP results of Study 1. (A) The P1 was maximal at occipital recording sites. No effects of word category were present. (B) The N1 was also maximal at occipital sites. No effects of word category were present. (C) The P300 had a parieto-occipital maximum and exhibited no reliable word category effects. (D) The LPP was maximal at parietal sites and sensitive to word category. It was larger for death-related, unpleasant and pleasant words compared to neutral words. Also, it was more sensitive to death-related over both unpleasant and pleasant words. (E) Grand average ERPs at Pz illustrate the LPP effects. Note the stimulus offset effect at 300 ms, which coincides with the P300. The data were low-pass filtered (10 Hz, 24 db/Oct) for display purposes.

Fig. 2

Fig. 2

Summary of the ERP results of Study 2. (A) The P1 was maximal at occipital sites. (B) The N1 also exhibited bilateral occipital maxima, but was not differentially sensitive to the word categories. (C) A clear parietooccipital P300 emerged, but was not influenced by word category. (D) The distribution of the LPP was somewhat more anterior compared to the P300. The LPP was sensitive to arousal in general: death-related, unpleasant and pleasant words elicited greater amplitudes. As in Experiment 1, it was also more sensitive to death-related over both neutral and unpleasant words. Unlike in Experiment 1, death-related and pleasant words did not differ. (E) Grand average ERPs at Pz. The data were low-pass filtered (10 Hz, 24 db/Oct) for display purposes.

References

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