Eating and wheel running across the estrous cycle in rat lines selectively bred on a taste phenotype

The Occidental Low- and High-Saccharin-Consuming rats (respectively, LoS and HiS) have been selectively bred for decades to study the relationship between taste and behaviors in and beyond the ingestive domain. Whether the saccharin phenotype is associated with behavioral periodicities tied to reproductive status is not known. Here we describe for the first time variation across the estrous cycle in chow intake and wheel running by LoS and HiS rats. This study also shed light on why rats, humans, and some other mammals eat less and become more active as fertility increases. Wheel running increases when eating is reduced through restricted chow access, more so in LoS rats than in HiS rats (Dess et al., 2000). If the decrease in food intake from diestrus through estrus causes the increase in running (Eat Less → Run More hypothesis, ELRM), then the running peak should follow the eating nadir and be greater in LoS rats. Bayesian cyclic regression showed that estrous cycles were shorter in LoS rats than in HiS rats; implications are discussed. Contrary to ELRM, the running peak did not follow the eating nadir, and cycle amplitude did not distinguish LoS rats from HiS rats. These results indirectly support the No Time To Eat hypothesis (Fessler, 2003), according to which the periovulatory eating nadir and running peak reflect fitness-enhancing consequences of shifts away from eating and toward mating as fertility increases.

The influence of mortality reminders on cultural in-group versus out-group takeaway food safety perceptions during the COVID-19 pandemic

During the early stages of the COVID‐19 pandemic takeaway food orders generally increased, yet sales of Chinese and Italian food declined. At this time, news sources ran stories on the safety of cuisine from these countries, frequently juxtaposed with communications on mortality‐related information related to the virus. Terror management theory suggests mortality concerns can lead people to defend against the psychological threat of death by bolstering positive evaluations of products and values of their own culture, and by disparaging products and values of other cultures. This translates to food preferences, with death reminders heightening consumption of food from one's own (vs. others’) culture. However, whether this extends to food safety perceptions has not yet been probed. In the present experimental study, we examine whether death reminders (vs. a control topic) led U.S. participants to view American takeaway food as safer to consume, relative to Chinese and Italian food. Results indicate that across conditions, American food was evaluated as safer relative to Chinese and Italian takeout. Further, American takeaway was seen as safer after mortality reminders (vs. a control topic), with no differences in safety evaluations for Chinese or Italian takeout. Results are discussed in relation to the COVID‐19 pandemic.

Benefits of heroes to coping with mortality threats by providing perceptions of personal power and reducing unhealthy compensatory consumption

Mortality threats are among the strongest psychological threats that an individual can encounter. Previous research shows that mortality threats lead people to engage in unhealthy compensatory consumption (i.e., overeating), as a maladaptive coping response to threat. In this paper, we propose that reminders of heroes when experiencing mortality threat increases perceptions of personal power, which in turn buffers the need to engage in unhealthy compensatory consumption. We test and find support for our predictions in a series of four studies that include real-world Twitter data after a series of terrorist attacks in 2016-2017, and three experimental studies conducted online and in the field with behavioral measures after Day of the Dead and during COVID-19 pandemic. These findings advance the literature on compensatory consumption, mortality threats, and the psychological functions of heroes.

Sweetener Intake by Rats Selectively Bred for Differential Saccharin Intake: Sucralose, Stevia, and Acesulfame Potassium

Behavioral responses to sweeteners have been used to study the evolution, mechanisms, and functions of taste. Occidental low and high saccharin consuming rats (respectively, LoS and HiS) have been selectively outbred on the basis of saccharin intake and are a valuable tool for studying variation among individuals in sweetener intake and its correlates. Relative to HiS rats, LoS rats consume smaller amounts of all nutritive and nonnutritive sweeteners tested to date, except aspartame. The lines also differ in intake of the commercial product Splenda; the roles of sucralose and saccharides in the difference are unclear. The present study extends prior work by examining intake of custom mixtures of sucralose, maltodextrin, and sugars and Splenda by LoS and HiS rats (Experiment 1A-1D), stevia and a constituent compound (rebaudioside A; Experiment 2A-2E), and acesulfame potassium tested at several concentrations or with 4 other sweeteners at one concentration each (Experiment 3A-3B). Results indicate that aversive side tastes limit intake of Splenda, stevia, and acesulfame potassium, more so among LoS rats than among HiS rats. In addition, regression analyses involving 5 sweeteners support the idea that both sweetness and bitterness are needed to account for intake of nonnutritive sweeteners, more so among LoS rats. These findings contribute to well developed and emerging literatures on sweetness and domain-general processes related to gustation.

Opposing Standards Within the Cultural Worldview: Terror Management and American Women's Desire for Uniqueness Versus Inclusiveness

Two different standards within American women's overall cultural worldview were examined in two studies: standing out and fitting in. American culture prescribes and values uniqueness, yet gender norms for women prescribe and value inclusiveness. Thus, unlike American men, American women encounter incongruent cultural norms that make it unclear which she will uphold when faced with thoughts of death. We hypothesized that, for women (and not men), gender salience would moderate worldview adherence. Using standard terror management manipulations, American women were subjected to a self or gender prime (Study 1) as well as a non-gender-group prime and compared to men (Study 2). Results showed that under mortality salience, women primed with gender identified more with their gender group, were more likely to behave inclusively, and were more likely to desire affiliation. In contrast, those primed with the self, a non-gender-group prime, as well as men, were more likely to desire uniqueness. These findings suggest that, for an American woman, both inclusiveness and uniqueness are responses to mortality salience, depending on her momentary reference point.

Gut Microbiota and a Selectively Bred Taste Phenotype: A Novel Model of Microbiome-Behavior Relationships

OBJECTIVES

The microbiota-gut-brain axis is increasingly implicated in obesity, anxiety, stress, and other health-related processes. Researchers have proposed that gut microbiota may influence dietary habits, and pathways through the microbiota-gut-brain axis make such a relationship feasible; however, few data bear on the hypothesis. As a first step in the development of a model system, the gut microbiome was examined in rat lines selectively outbred on a taste phenotype with biobehavioral profiles that have diverged with respect to energy regulation, anxiety, and stress.

METHODS

Occidental low and high-saccharin-consuming rats were assessed for body mass and chow, water, and saccharin intake; littermate controls had shared cages with rats in the experimental group but were not assessed. Cecum and colon microbial communities were profiled using Illumina 16S rRNA sequencing and multivariate analysis of microbial diversity and composition.

RESULTS

The saccharin phenotype was confirmed (low-saccharin-consuming rats, 0.7Δ% [0.9Δ%]; high-saccharin-consuming rats, 28.1Δ% [3.6Δ%]). Regardless of saccharin exposure, gut microbiota differed between lines in terms of overall community similarity and taxa at lower phylogenetic levels. Specifically, 16 genera in three phyla distinguished the lines at a 10% false discovery rate.

DISCUSSION

The study demonstrates for the first time that rodent lines created through selective pressure on taste and differing on functionally related correlates host different microbial communities. Whether the microbiota are causally related to the taste phenotype or its correlates remains to be determined. These findings encourage further inquiry on the relationship of the microbiome to taste, dietary habits, emotion, and health.

Two decades of terror management theory: a meta-analysis of mortality salience research

A meta-analysis was conducted on empirical trials investigating the mortality salience (MS) hypothesis of terror management theory (TMT). TMT postulates that investment in cultural worldviews and self-esteem serves to buffer the potential for death anxiety; the MS hypothesis states that, as a consequence, accessibility of death-related thought (MS) should instigate increased worldview and self-esteem defense and striving. Overall, 164 articles with 277 experiments were included. MS yielded moderate effects (r = .35) on a range of worldview- and self-esteem-related dependent variables (DVs), with effects increased for experiments using (a) American participants, (b) college students, (c) a longer delay between MS and the DV, and (d) people-related attitudes as the DV. Gender and self-esteem may moderate MS effects differently than previously thought. Results are compared to other reviews and examined with regard to alternative explanations of TMT. Finally, suggestions for future research are offered.

Psychological defenses against death anxiety: integrating Terror Management Theory and Firestone's Separation Theory

The author attempts to integrate Terror Management Theory (TMT) and R. W. Firestone's Separation Theory (1984, 1994). Both theories emphasize defense against death anxiety as a key human motive. Whereas TMT focuses extensively on self-esteem and cultural worldview, Firestone posited additional defenses such as gene survival, self-nourishing behaviors, addictive couple bonds, and adopting an anti-sexual approach to life. TMT offers a strong base of experimentally validated ideas and the experimental paradigms to test the broad array of defenses enumerated in Firestone's Separation Theory. Therefore, an integration of the two theories would be beneficial to a fuller understanding of psychological defenses against death anxiety.