Life history theory predicts that exposure to extrinsic mortality threats early in life leads to a faster life history strategy characterized by preference for present versus future outcomes. The condition of one's body also determines the probability of survival. With this in mind, we predicted that a marker of damage to one's body, levels of the proinflammatory cytokine IL-1β, would also promote preference for present over delayed outcomes.
We found that levels of serum IL-1β predicted more reported impulsivity, less preference for delaying gratification, and a more present temporal orientation. Additonal analyses suggest that environmental stress may partially exert its effect on temporal focus through somatic damage.

From the perspective of Terror Management Theory (TMT), humans hold the potential to experience paralyzing terror due to the understanding of our eventual death. This terror results from the effort to reconcile death awareness and the evolutionary struggle to survive. While TMT research has accumulated many significant findings since its origination, basic assumptions of this theory have recently been challenged. Some critics are pointed out that there is no direct evidence for the experience of “terror” within the TMT literature (Marten & van den Bos ,2014) as mortality salience (MS) effects have been largely observed through the use of self-reported questionnaires and a terror after MS manipulation is mostly inferred. The current study attempts to address these concerns by seeking to obtain the confirmation of unconscious terror to mortality salience measured via salivary cortisol response.

Songbirds are an appealing animal model for speech acquisition partially due to the fact that they are also vocal learners, meaning they acquire their vocalizations through imitation (Doupe & Kuhl, 1999). Birdsong is defined as a "chain of discrete acoustic elements arranged in a particular temporal order" (Berwick et al. 2011). While Bengalese finches (Lonchura striata domestica) have a repertoire of 8-12 syllables (i.e. acoustic elements), the sequence of these syllables can vary according to set patterns and rules. Song sequence stereotypy, linearity and consistency are measures of syntax. The Bengalese finch song is semi-variable. Some syllable-to-syllable combinations are fixed, whereas some syllables (hereafter, “branching syllables) can be followed by multiple syllables (hereafter, “branching points”). In the avian brain, two different neural pathways are responsible for song acquisition and production, and both pathways are controlled by the avian premotor nucleus, HVC (proper name). Previously, we have found that male Bengalese finches show initial acoustic impairment and gradual recovery over the course of seven days after small, unilateral HVC microlesions (right hemisphere = 4, left hemisphere = 4). Here we explore whether HVC contributes to maintaining and recovering song syntax, as well as potential differential effects of lefts versus right HVC microlesions. To answer these two questions, we analyzed the syntax of previously collected songs at three different time points: baseline (pre-surgery), post-surgery day 4 (PSD4), and post-surgery day 7(PSD7). Each syllable was assigned a unique label, however, due to the extent of song degradation at PSD4, we did could not “match” syllables across days. Using an online java applet, the Songinator (Zevin, Seidenberg & Bottjer, 2004), we computed scores for stereotypy, linearity and consistency. Using a 2 x 3 repeated-measures ANOVA, we did not find any significant differences across time points for stereotypy (F(1.09, 6.53) = 0.18, p = 0.40), linearity (F(2,12) = 0.94, p = 0.42), or consistency (F(2, 12) = 0.63, p = 0.55). We also did not find an interaction effect for stereotypy (F(1.09, 6.53) = 0.84, p = 0.41), linearity (F(2, 12) = 1.25, p = 0.32), or consistency (F(2, 12) = 0.27, p = 0.77). However, we observed that right HVC microlesions exhibited increased linearity over time (Pre: 0.29 ± 0.02, PSD4: 0.31 ± 0.02, PSD7: 0.34 ± 0.01) . We examined this finding in more detail by computing the a change ratio (PSD4/pre-surgery) for the number of syllables and the average number of branching points per syllable. We found that HVC damage increased the number of unique syllables in both groups. Interestingly, there was also an increase in the number of branching points, but only in the left HVC group, compared to the right HVC microlesion (t(6) = 1.853, p = 0.057, one-tailed). These results support previous findings that HVC lesions disrupt vocal production and suggest novel syllables are the result of impaired motor control. These results also suggest that control of song syntax is somewhat lateralized. Left HVC microlesions initially impair the birds’ ability to produce a stereotyped song by making syllable transitions more variable. Therefore, the right HVC controls song variability, and left HVC song stereotypy.

Terror management theory suggests that when mortality concerns are salient, religion can serve as a defense in an attempt to boost self-esteem and shield against the potential for anxiety. Interestingly, however, very little research has been conducted on people who actively question their religious beliefs in order to attain a better understanding (i.e., quest religiosity). Recent research suggests that quest religiosity moderated the effects of mortality salience in that participants who were high in quest religiosity experienced a decrease in self-esteem following reminders of death. Building on these findings, the current studies further examined quest religiosity to extend to underlying death cognitions and fear of death. Study 1 found that individuals who were high in quest religiosity experienced a greater accessibility of death-related thoughts. Additionally, Study 2 demonstrated that quest religiosity fully mediated the relationship between fear of death and well-being among religious individuals. Specifically, high fear of death predicted greater quest religiosity that, in turn, predicted lower well-being. These results suggest an associative link between fear of death and quest. Importantly, religion can serve as a buffer for existential terror but questioning these beliefs lowers their efficacy and impacts well-being.

Previous research suggests that individuals pursue close relationships because they help people cope with mortality awareness (Mikulincer, Florian, & Hirschberger, 2003). Further, there is some evidence to suggest that individuals achieve a sense of death transcendence through the prospect of parenthood. For example, following reminders of death, people have a greater desire for children (e.g., Wisman & Goldenberg, 2005), have more vivid and accessible parenthood-related cognitions (Yaakobi, Mikulincer, & Shaver, 2014), and are more negative toward strict birth-control policies and more positive toward younger family members (Zhou, Liu, Chen, & Yu, 2008). However, no prior work has examined parenting behaviors directly. For this reason, the purpose of the present research was to examine whether people display more behaviors associated with responsive caregiving following reminders of mortality. Participants were exposed to a mortality salience manipulation in which they were randomly assigned to complete items relating to their fear of death or public speaking (the control condition). Following this, everyone took part in a simulated baby paradigm to assess participants’ responses to a simulated infant doll that was programmed (wirelessly) to begin crying inconsolably (Rutherford, Goldberg, Luyten, Bridgett, & Mayes, 2013). The extent to which participants engaged in caregiver-based touching behaviors (i.e., holding the baby in a meaningful way in an attempt to calm or soothe the baby) toward the simulated crying infant served as the dependent variable. The results revealed that, in comparison to the control condition, reminders of death led participants to engage in a greater degree of caregiver-based touching behaviors while interacting with a simulated crying infant. Overall, these initial findings suggest that reminders of death influence actual caregiving behaviors and suggest that people may display more optimal parenting behavior in the real world when thoughts of death are salient.