Neural Correlates of Mating System Diversity: Oxytocin and Vasopressin Receptor Distributions in Monogamous and Non-Monogamous Eulemur

Nicholas M. Grebe, Annika Sharma, Sara M. Freeman, Michelle C. Palumbo, Heather B. Patisaul, Karen L. Bales & Christine M. Drea. "Neural Correlates of Mating System Diversity: Oxytocin and Vasopressin Receptor Distributions in Monogamous and Non-Monogamous Eulemur." Scientific Reports, February 12, 2021. DOI: 10.1038/s41598-021-83342-6

Abstract: Contemporary theory that emphasizes the roles of oxytocin and vasopressin in mammalian sociality has been shaped by seminal vole research that revealed interspecific variation in neuroendocrine circuitry by mating system. However, substantial challenges exist in interpreting and translating these rodent findings to other mammalian groups, including humans, making research on nonhuman primates crucial. Both monogamous and non-monogamous species exist within Eulemur, a genus of strepsirrhine primate, offering a rare opportunity to broaden a comparative perspective on oxytocin and vasopressin neurocircuitry with increased evolutionary relevance to humans. We performed oxytocin and arginine vasopressin 1a receptor autoradiography on 12 Eulemur brains from seven closely related species to (1) characterize receptor distributions across the genus, and (2) examine differences between monogamous and non-monogamous species in regions part of putative “pair-bonding circuits”. We find some binding patterns across Eulemur reminiscent of olfactory-guided rodents, but others congruent with more visually oriented anthropoids, consistent with lemurs occupying an ‘intermediary’ evolutionary niche between haplorhine primates and other mammalian groups. We find little evidence of a “pair-bonding circuit” in Eulemur akin to those proposed in previous rodent or primate research. Mapping neuropeptide receptors in these nontraditional species questions existing assumptions and informs proposed evolutionary explanations about the biological bases of monogamy.

Discussion

As the first study to investigate neuropeptide receptor distribution in strepsirrhine primates, we document binding patterns of both oxytocin and vasopressin in members of the Eulemur clade that fall between those of classic rodent models (e.g.18,19) and those of more recently characterized haplorhine primates46,47,57. This intermediacy may have functional implications for lemurs’ evolutionary specializations, potentially reflecting the comparatively variable role of these neuropeptides in sensory ecology (e.g.13,58). As the first primate study to directly compare neuropeptide receptor binding between brain specimens from monogamous and non-monogamous species of the same genus, our findings also fill a critical gap in knowledge of how variation in neuroanatomy reflects variation in primate mating systems or sociality. Beyond simply representing another data point in the domain of comparative neurology, findings from our study of Eulemur question the universality of classic vole models and suggest a revisitation of their implications for humans.

Like rodents, lemurs show olfactory specialization59, which is prominently displayed in their use of scent to convey a wide array of reproductive and social information60,61. Some degree of similarity in the involvement of OXTRs in processing chemically encoded socio-reproductive information in these taxa is suggested by the diffuse binding of both OXTR and AVPR1a in the olfactory bulbs and olfactory tubercle, and by dense binding of AVPR1a in the CeA and BNST (across mating systems). Likewise, AVPR1a binding has been found in the olfactory bulb of platyrrhine primates (e.g. common marmosets;57) that also rely extensively on olfactory communication62; similar binding has not been reported in less olfactory-oriented catarrhine primates.

Relative to other placental mammals, vision is exceptionally well-developed in primates, but less so in strepsirrhines than in haplorhines. In catarrhines, for example, trichromacy63,64 and visual gaze are particularly important in reproductive and social communication65,66. Consistent with previous work in haplorhine primates, we found OXTR expression in V1 and the LGN across species, and AVPR1a expression in these and additional areas related to visual attention (i.e., Rtg, SC, and amygdalar nuclei); nevertheless, binding in Eulemur was less widespread than that observed in haplorhine primates (e.g.46,47). With regard to sensory pathways, therefore, our results are consistent with lemur neuroanatomy representing a bridge between odor-reliant rodents and vision-reliant haplorhines.

Intermediary patterns were also evident in other pathways. For instance, consistent with findings in some rodent species (singing mice:23; prairie and montane voles:19), but unlike findings in haplorhine primates, we observed dense AVPR1a expression in the MGN of lemurs. Because the MGN is an essential auditory relay nucleus—receiving input from the inferior colliculus and projecting to the auditory cortices—our findings potentially implicate vasopressin in another sensory modality in Eulemur; it is possible that vasopressin plays a modulatory role in the processing of vocal communication or emotionally valent sounds.

Relative to haplorhines, additional patterns of receptor binding in Eulemur show both similarities and striking reversals. In Eulemur, we observed strong AVPR1a binding, but diffuse or modest OXTR binding, in both the striatum and hippocampal regions. This striatal pattern is comparable to that seen in coppery titi monkeys47, but it contrasts with the dense OXTR expression found in both rodents67 and marmosets57. Hippocampal patterns in Eulemur are reversed from that observed in titi monkeys47. Oxytocin acting on OXTRs in the NAcc is necessary for pair-bond formation in voles4. Precise functions of oxytocin or vasopressin within the hippocampal formation remain to be identified68, but there is some evidence that they modulate the encoding and consolidation of socially relevant memories69,70. In any event, our divergent results in these regions suggest that neural mechanisms of pair bonding in lemurs may differ substantially from other mammalian groups studied thus far.

Regarding the influential hypothesis that interspecific variation in specific populations of receptors reflects variation in social organization or mating system, our results did not reveal comparable differences to the striking findings previously reported for monogamous and non-monogamous vole species. For instance, in Insel and Shapiro18, the effect size for a mating system difference in OXTR was d = 2.23 in the NAcc and d = 2.06 for the LA; in Insel et al.19, the mating system difference in AVPR1a was d = 3.66 for the LS and d = 2.81 for the BNST. In Eulemur, despite a sample size that matched these classic vole studies, differences between mating systems, for either neuropeptide, were almost uniformly non-significant (with much smaller effect sizes; all d < 0.8) in all regions of a hypothesized rodent ‘pair-bonding circuit’. Our results do not support the suggestion that OXTR/AVPR1a differences in key dopaminergic areas separate monogamous from non-monogamous species4. When expanding our comparisons across the entire brain, however, we observed some significant differences between mating systems, including in the Rtp for OXTR and the VA Thal, DR, and PFC for AVPR1a.

How should one interpret these mixed results? Regarding null findings, we note that exhausting the available bank of Eulemur brain tissue at the Duke Lemur Center nevertheless left us with limited statistical power to detect differences in individual regions as a function of mating system. While large differences comparable in magnitude to those reported in Insel and Shapiro18 and Insel et al.19 would be detectable with our sample—indeed, we matched the sample size from these classic studies—more modest differences may have been missed. Regarding exploratory positive findings, we first caution that examining numerous regions increases the potential for false-positives, and that there is a lack of information about the functional significance for many of these differences. For instance, whereas the presence of OXTR in the pontine reticular areas of Eulemur and rhesus macaques46 suggests a possible conserved function of oxytocin in this region, it is unclear how differences in this region that controls horizontal gaze and saccadic eye movement would be involved in differences in social bonding behavior. Although the ventral anterior thalamus has important functions in spatial memory and learning71, it has not been specifically implicated in pair-bonding processes. That said, other findings more readily yield potential interpretations. First, the AVPR1a difference we observed in the DR, a source of serotonin and a region involved in reward-seeking and reward-tracking behavior72, suggests that some of the effects of vasopressin on social behavior may owe to activation of the DR serotonin system73. If so, monogamous Eulemur may have developed denser populations of AVPR1a to bolster serotonergic functions of social reward behavior that foster the creation of pair bonds. Second, rather than observing OXTR binding differences in the PFC—a key area generating the reinforcing, hedonic properties of pair-bonding behavior and mating in rodents4—we instead found a difference in AVPR1a binding in this region. Perhaps some of the mechanisms mediated by oxytocin in rodents are carried out by the structurally similar vasopressin in primates—a suggestion that has been hypothesized and substantiated in several previous studies45.

Collectively, mixed findings for mating system differences, like the aforementioned binding patterns found across lemur species, are consistent with the existence of distinctive mechanisms for the formation of monogamous mating systems in Eulemur. In questioning the universality of these mechanisms across mammalian groups, our findings in this domain can also be considered within the broader context of psychological oxytocin research, which is similarly marked by interpretive challenges and heterogeneous findings (e.g.74). We suggest that expanding the toolkits available to researchers, including broadening the animal models studied, will likely continue to reveal unexpected findings that require modification to existing theory (a point echoed by behavioral ecologists; e.g.75).

Providing context to our results is the fact that numerous factors other than species identity influence an individual’s oxytocin and vasopressin neurocircuitry. Neurobiology is not static throughout the lifespan, but rather may vary seasonally, with social circumstance, and with age or life-history stage (e.g.52). Thus, while receptor distributions can differ widely between species and social systems18,19,22, they might also differ substantially within individuals of the same species or mating system. Indeed, Phelps and Young27 report intraspecific variation in AVPR1a binding among prairie voles often comparable to or greater than interspecific variation (for a recent example of experience-dependent, intraspecific OXTR patterns in a primate model, see68). Nevertheless, these same authors also report less variation in regions regulating social bonding, relative to those unrelated to social bonding—a pattern consistent with natural selection winnowing neuropeptide expression in these former regions. We also observed substantial intraspecific and within-mating system variation in Eulemur (see individual-level estimates of receptor profiles in Table S3)—given our limited sample size per species, it is unclear to what extent this might be explained by season-level, individual-level, and/or species-level differences. In Eulemur, some areas previously identified as key to social bonding—such as nuclei of the amygdala and the BNST—showed relatively small coefficients of variation within mating systems, consistent with27, even though they did not differ significantly between mating systems. Other regions that showed relatively little variation within Eulemur mating systems, such as the primary visual cortex and SC, were not the same ones identified as part of a pair-bonding circuit in rodent studies, but they are consistently identified as sites of OXTR and AVPR1a in nonhuman primate studies46,47. Perhaps neuropeptide binding in regions responsible for processing visual information are important targets of stabilizing selection in primates, regardless of the underlying mating system.

As in the classic vole studies18,19, we categorized our Eulemur species as belonging to one of two broad mating systems, based on extant information about their wild counterparts39. On the one hand, we cannot rule out the possibility that group size reductions, selective reproduction, or long-term pair housing in captivity may have contributed to ‘monogamous-like’ receptor binding profiles across species in our sample, potentially minimizing differences by mating-system category. On the other hand, one might expect such a ‘flattening’ influence to lead to similar receptor profiles across individuals and species, but this does not reflect our results, which are more accurately characterized by a large degree of within-mating system variation. More generally, we believe our results complement the recognition of substantial, natural heterogeneity in social behavior, within or between species, under the general umbrella of ‘monogamous’ or ‘non-monogamous’. Pair-living, pair-bonding, and genetic monogamy are overlapping, yet constitute distinct components of a monogamous mating system that are often conflated40,76. Different configurations of these components across ‘monogamous’ species could conceivably create different neuropeptide receptor distributions. Importantly, we note that flexibility in putative mating systems is likely the norm, rather than the exception in animal models. Even the seemingly well-characterized mating system of prairie voles contains surprises revealed only upon extensive observation in naturalistic settings26. In some cases, differences in neuropeptide receptor distributions may be detectable in spite of intraspecific (or within-mating system) social variation, but this may less common than previously assumed.

People generally prefer not to be the topic of gossip, especially when negative, but a non-trivial minority (about 1/3) actually prefer to be talked about than ignored; this preference is stronger in men & in self-reported narcissists

The Oscar Wilde Dilemma: Understanding When People Want to be the Topic of Gossip. Andrew Hales, Meltem Yucel, Selma Rudert. Society for Personality and Social Psychology, conference 2021, Feb 11, 2021. https://whova.com/embedded/subsession/cecli_202103/1392301/1392305/

Description: When, if ever, do people want to be talked about behind their back? An experiment with a nationally representative sample (N = 1,900) indicated that people generally prefer not to be the topic of gossip, especially when negative. However, a non-trivial minority (about one-third) actually prefer to be talked about than ignored. This preference is stronger in men and in self-reported narcissists.

Going for Woke: White Americans Downshift Conservatism in Interracial Settings

Going for Woke: White Americans Downshift Conservatism in Interracial Settings. Olivia Foster-Gimbel. Society for Personality and Social Psychology, conference 2021, Feb 10, 2021. https://whova.com/embedded/subsession/cecli_202103/1447262/1447263/

Description: For White Americans, interracial interactions can induce concerns about appearing prejudiced, prompting behavioral shifts in interracial (versus same-race) interactions (Bergsieker et al., 2010; Dupree & Fiske, 2018) . The current research tests whether White Americans shift their self-presentation of political preferences when responding to a Black versus a White interaction partner. In four studies (N=3125), White participants created a profile that they believed would be forwarded to a presumed-real Black or White partner. Meta-analysis revealed that White Americans presented themselves as less supportive of conservative policies and politicians when responding to a Black (versus White) interaction partner. This effect was mediated by perceptions of partner ideology. White Americans perceived a Black partner as significantly less conservative than a White partner, driving this “conservative downshift”. Finally, Black Americans (n = 337) were more willing to interact with a White partner who downshifted conservatism, rating them as more likeable and less biased. White Americans’ political preferences shift based on the audience, with consequences for interracial affiliation.

Utilitarianism: Collectives were more utilitarian than the statistical aggregate of their members; it seems deliberation and consensus within a group transiently reduced the emotional burden of norm violation

Many heads are more utilitarian than one. Anita Keshmirian. Society for Personality and Social Psychology, conference 2021, Feb 10, 2021. https://whova.com/embedded/subsession/cecli_202103/1447352/1447368/

Description: Moral judgments have a very prominent social nature and in everyday life they are continually shaped by discussions with others. Psychological investigations of these judgments, however, have rarely addressed the impact of face-to-face interaction. To examine the role of social deliberation within small groups on moral judgments, we had groups of 4 to 5 participants judge moral dilemmas first individually and privately, then collectively and interactively and finally individually a second time. We employed both real-life and sacrificial moral dilemmas in which the character’s action or inaction violated a moral principle to benefit the greatest number of people. Participants decided if these utilitarian decisions were morally acceptable or not. We found that collectives were more utilitarian than the statistical aggregate of their members compared to both first and second individual judgments. This supports the hypothesis that deliberation and consensus within a group transiently reduced the emotional burden of norm violation and indicates normative conformity in moral judgments.

Excavation at three Late Prehistoric Eskimo sites in arctic Alaska has revealed the presence of Venetian glass trade beads in radiocarbon-dated contexts that predate Columbus's discovery of the Western Hemisphere

A Precolumbian Presence of Venetian Glass Trade Beads in Arctic Alaska. Michael L. Kunz, Robin O. Mills. American Antiquity, January 2021. https://www.cambridge.org/core/journals/american-antiquity/article/abs/precolumbian-presence-of-venetian-glass-trade-beads-in-arctic-alaska/3465746929B31ADBC6E1D1A23D09A2CD#

Abstract: Excavation at three Late Prehistoric Eskimo sites in arctic Alaska has revealed the presence of Venetian glass trade beads in radiocarbon-dated contexts that predate Columbus's discovery of the Western Hemisphere. The bead variety, commonly known as “Early Blue” and “Ichtucknee Plain,” has been confirmed by expert examination and comparative Instrumental Neutron Activation Analysis (INAA). The beads are present in sites throughout the Caribbean, the eastern coast of Central and North America, and the eastern Great Lakes region, where they are commonly found in sites dating between approximately AD 1550 and 1750, although a diminishing presence continues into the early 1800s. Beads of this variety have not previously been reported from Alaska. Ascribed to Venetian production by their precolumbian age, the beads challenge the currently accepted chronology for the development of their production methodology, availability, and presence in the Americas. In the absence of trans-Atlantic communication, the most likely route these beads traveled from Europe to northwestern Alaska is across Eurasia and over the Bering Strait. This is the first documented instance of the presence of indubitable European materials in prehistoric sites in the Western Hemisphere as the result of overland transport across the Eurasian continent.

Engaging in pro-environmental behaviours can increase one’s desirability in the mating market; & people display a motivation to engage in pro-environmental behaviours in the presence of attractive, opposite sex targets

Farrelly, Daniel, and Manpal S. Bhogal. 2021. “Mate Choice Enhances Pro-environmentalism.” PsyArXiv. February 13. doi:10.31234/osf.io/sepj9

Abstract: Previous research shows that altruistic behaviour is important in mate choice. A plethora of research shows that people are attracted to altruistic mates, and in turn, display altruistic behaviours towards those they find attractive. However, most of this research has focused on everyday altruism. Here, we apply this theoretical framework to pro-environmental behaviours, which are important altruistic behaviours, considering there is a time cost involved in engaging in such behaviours. In addition, encouraging people to engage in pro-environmental behaviours has great implications for the protection of our planet. Here, across two experiments, we successfully show that engaging in pro-environmental behaviours can increase one’s desirability in the mating market (experiment 1, n = 157) and that people display a motivation to engage in pro-environmental behaviours in the presence of attractive, opposite sex targets (experiment 2, n= 307). These are exciting and novel research findings, whereby we show that we can increase pro-environmental behaviours via mate choice motivation and also demonstrate their positive role in mate evaluation. These findings have implications for marketing and increasing environmental behaviour through the lens of evolutionary theory.

Check also Bhogal, M. S., & Bartlett, J. E. (2020). Further support for the role of heroism in human mate choice. Evolutionary Behavioral, Sep 2020. https://www.bipartisanalliance.com/2020/09/men-and-women-reported-higher.html

And The role of altruistic costs in human mate choice. Manpal Singh Bhogal et al. Personality and Individual Differences, Volume 160, 1 July 2020, 109939. https://www.bipartisanalliance.com/2020/02/human-mate-choice-individuals.html

And The role of prosocial behaviors in mate choice: A critical review of the literature. Manpal Singh Bhogal, Daniel Farrelly, Niall Galbraith. Current Psychology, May 27 2019. https://www.bipartisanalliance.com/2019/05/most-research-has-found-that-people.html

Liberals and Conservatives Show Equal Group Bias in Sharing Behavior: there are no ideological differences in actual behavior despite previous literature indicating differences in attitude/intention measures

Liberals and Conservatives Show Equal Group Bias in Sharing Behavior. Onurcan Yilmaz. Society for Personality and Social Psychology, conference 2021, Feb 9, 2021. https://whova.com/embedded/subsession/cecli_202103/1447166/1447200/

Rolf Degen's take: The left and the right were equally inclined to give away a larger share of the pie to people from their own camp

Description: A long-standing debate revolves around the question whether liberals and conservatives differ in their tendency for group bias. The ideology asymmetry hypothesis predicts less group bias among liberals than conservatives whereas the symmetry hypothesis expects identical group bias for both liberals and conservatives. We provide a large-scale (N=1,347) preregistered experiment testing the predictions of the asymmetry hypotheses: previously identified liberals and conservatives played Dictator Games with either an in- or out-group member, either under time-pressure (<5s) or time-delay (>20s). Although the manipulation worked as intended, we found no effect of time pressure on either group bias or on dictator sharing behavior. However, substantial group bias was observed in nearly identical amounts among liberals and conservatives. Both liberals (17.1%) and conservatives (16.3%) shared more with their in-groups. These findings suggest that there are no ideological differences in actual behavior despite previous literature indicating differences in attitude/intention measures.

Participants experienced greater momentary happiness when not experiencing a desire compared to experiencing acute desire; & the greater the desire conflicted with important goals the lower the momentary happiness

Testing Buddha: Is Acute Desire Associated with Lower Momentary Happiness? Stephen L. Murphy, Yuka Ozaki, Malte Friese & Wilhelm Hofmann. Journal of Happiness Studies, Feb 12 2021. https://rd.springer.com/article/10.1007/s10902-021-00362-9

Abstract: A central Buddhist claim is that having desires causes suffering. While this tenet draws from the belief that an acute desire state is more momentarily aversive than a no-desire state, the efficacy of this belief has yet to be comprehensively examined. To empirically investigate this claim, we furnished data from two experience sampling studies across USA/Canadian (N = 101; 3224 observations) and Japanese cultures (N = 237; 8497 observations). We compared states of acute desire with states of no desire regarding momentary happiness. We then tested, in an additional step, whether acute desires at greater conflict with personal goals were associated with even lower levels of momentary happiness. Findings were consistent across studies, with participants experiencing greater momentary happiness when not experiencing a desire compared to experiencing acute desire. Also, the greater the desire conflicted with important goals the lower the momentary happiness. The present findings support a key basis of the Buddhist belief that having desires causes suffering, showing acute desire states on average to be more aversive than no desire states.

General Discussion

Buddhism claims that having desires is the root of all suffering (Burton 2010). Nonetheless, a key foundation of this popular tenet had yet to be comprehensively examined—that individuals are, on the whole, momentarily happier when not experiencing a desire compared to when they are experiencing an acute desire. Across two culturally-divergent experience-sampling studies, and in support of our ‘Buddha hypothesis’, findings aligned with Buddhist tenets in showing momentary happiness was indeed greater when individuals were without desire compared to when they were experiencing an acute desire. Fine-grained analyses revealed that acute desires in greater conflict with important personal goals were associated with lower momentary happiness.

The present study investigated whether acute desire states were associated with lower momentary happiness relative to desire states given this theorized effect had yet to be comprehensively tested (Cooney et al. 1987; Kavanagh et al. 2005). Finding support for this effect was also valuable given the notion that acute desire states are aversive relative to no desire states is a foundational Buddhist belief that underpins their more popular tenet that having desires causes suffering. The present study’s findings perfectly aligned with this ‘Buddha Hypothesis’ that acute desire states would be more aversive than no desire states. Importantly, these findings build upon the weaknesses of past research that generally show acute desire states can be aversive (e.g., Cooney et al. 1987; Kavanagh et al. 2005). The present study showed that acute desire states were on average more aversive than no desire states. While unknown whether having desires is associated with lower temporally-stable forms of happiness, the present findings add some weight by supporting the efficacy of key belief upon which this view is based (although it should be borne in mind that pleasure from satisfying desires may yet attenuate, extinguish, or even crowd out the affective consequences of acute desire states). The present findings also keep desire-related research in the spotlight (e.g., Hofmann et al. 2012), highlighting that greater consideration of desire states may be critical for better understanding important processes and outcomes.

This research has various strengths, not least that identified effects were replicated and found to be of a similar magnitude across studies (dStudy1 = 0.62, dStudy2 = 0.71). That our findings were based upon data drawn from American/Canadian as well as Japanese participants also reduces (although does not eliminate) concerns that the identified effects were culturally specific. For instance, clear cultural differences in mean momentary happiness existed between Study 1 and Study 2. This finding corresponds with divergence in World Happiness Rankings between these nations (Japan, America, and Canada are placed 58th, 19th, and 9th, respectively, where higher rankings reflect happier nations; Helliwell et al. 2019). Nonetheless, we found momentary happiness was similarly reduced across studies when desires were acute rather than absent. A further strength of the present findings is that they came from data gathered at random times seven times a day during all typical waking hours, on all weekdays, in a large participant group, and across a large (unrestricted) number of desire-related domains. Ecological validity in this study was thus high. Indeed, it was the ecologically valid nature of this data, and the need for any strong test of the ‘Buddha Hypothesis’ to be based upon ecologically valid data, that motivated the present research.

Another strength of the present research was evidence highlighting differences in momentary happiness did not manifest due to a relatively high prevalence of acute desires in high- rather than low-conflict with important personal goals (i.e., across studies low-conflict acute desires were more frequently experienced). This potential explanation for reported differences inexplicably arises given that theory and literature suggest that conflicting (rather than unconflicting) desires require more effort and are generally more aversive (Dreisbach and Fischer 2012; Saunders et al. 2017). Nonetheless, in both studies, low-conflict (acute) desires were more prevalent than medium- or high-conflict desires, and low-conflict desires were also associated with less momentary happiness relative to having no desire. Finally, we did not hypothesize a magnitude for the proposed effects. Irrespective, our findings were consistent with both religious and psychological accounts that effects between desire and no desire are unlikely to be minor (e.g., Kavanagh et al. 2005). Specifically, the identified medium effect across Study 1 and Study 2 in unstandardized metric equated to a nearly 1-point difference on a 7-point scale.

Nonetheless, it is also important to bring attention to a key alternative explanation for our findings. That is, although conceived, in line with Buddhist tenets, that an acute desire state would reduce momentary happiness relative to a no desire state, it yet remains possible this identified effect reflected (at least in part) the reverse causal sequence—that lower (higher) momentary happiness gave rise to an acute (no) desire state. Indeed, this causal direction is equally conducive as it’s opposite with the present findings. Furthermore, this reverse causal sequence has theoretical and empirical support—aversive states like stress, fatigue, and emotional distress are well acknowledged to orient individuals towards more immediately gratifying opportunities (Tice et al. 2001). Accordingly, although considerable support exists to suggest acute desire promotes an aversive state (Kavanagh et al. 2005), that the present study was methodologically constrained in its ability to make strong causal claims demands the veracity of the reverse causal sequence should not be overlooked.

A secondary aim of the present study was to examine whether (acute) desires in greater conflict with important personal goals would, overall, be associated with lower levels of momentary happiness relative to having no desire. We hypothesized that momentary happiness would be lower, relative to the no desire state, when the degree of conflict with important goals was higher. Parts of this effect were established previously in a different sample, but without a more fine-grained analysis of degree of conflict, and without the crucial no desire baseline (Hofmann et al. 2013). Findings across both studies reported here provided a more generalizable basis for this claim, showing greater momentary happiness when conflict with personal goals was low or medium rather than high, and that even low conflict states were still experienced as lower in momentary happiness than no desire states.

Limitations

A first limitation of the present findings has been highlighted—that causality cannot be inferred in the present correlational research. Therefore, caution is warranted in concluding that desire-related variables (e.g., acute vs. no desire; low vs. high conflict) may have caused differences in momentary happiness. For instance, it is possible participants, in moments they were less (more) momentarily happy, were more likely to have (no) desires. This limitation can be remedied in future laboratory-based settings or in research using ecological momentary interventions (e.g., Heron and Smyth 2010).

A second limitation is given by the relatively low number of acute desire experiences utilized for the present purpose. These relatively low numbers prevented exploratory analyses of interest—e.g., to examine whether the domain in which acute desires arose moderated the extent to which level of conflict with other personal goals associated with momentary happiness. However, the decision to not include satisfied desire experiences in our analyses was an important one to prevent confounding effects. Despite the low number of cases, results across the two studies appeared quite robust and replicated well in the two different cultural settings. This provides some confidence in the robustness and generality of findings.

A third limitation is that, although our sample was heterogenous, approximately 78% of our sample in Study 1 was Caucasion. This renders it unknown whether our results would replicate in a more diverse sample. This argument can be extended to other characteristics. For instance, a high percentage of participants in both samples were college/university educated; much fewer participants exhibited lower educational attainment. Future research should aim to remedy this issue by testing this Buddha Hypothesis using a more diverse sample.

A final limitation is that the data furnished for this study precluded the possibility of examining whether desire-related variables (e.g., acute vs. no desire; low vs. high conflict) associated with more temporally-stable representations of happiness (momentary representations of happiness were available only). While the high frequency in which acute desires are experienced in typical daily life suggests momentary decrements in happiness may hinder broader representations of happiness (e.g., life satisfaction, wellbeing), this transfer effect was not examined and thus is not supported. Buddhist tenets primarily concern the chronic rather than acute effects of desire-related instances (i.e., how desire influences happiness in general rather than in momentary instances). Future research should therefore aim to explicitly measure more temporally-stable representations of happiness to ensure a more robust test of Buddhist arguments.

A majority of people all over the world reported that people today are less moral than they used to be; they reported that people in general have declined but that their friends and family have actually improved morally

The Illusion of Moral Decline. Adam Mastroianni. Society for Personality and Social Psychology, conference 2021, Feb 9, 2021. https://whova.com/embedded/subsession/cecli_202103/1447166/1447171

Description: People think that morality has declined, and they appear to be wrong. In nearly 400 public opinion surveys, a majority of people all over the world reported that people today are less moral than they used to be. We confirmed this finding in our own nationally representative survey and found that Americans think decline has been happening at least since their birth. In fact, they believe the decline is so rapid that people today are worse than people were even four years ago. Contrary to expectations, younger participants perceived just as much decline as older participants. In a follow up study, participants reported that people in general have declined but that their friends and family have actually improved morally. These effects were robust across a variety of moral attitudes and behaviors. Finally, a meta-analysis of another 127 nationally representative surveys strongly suggests that the perception of moral decline is an illusion: indicators of morality show essentially zero change over time.

 

Women who ate chocolate more frequently reported less interest in sex; popular portrayals in which chocolate is represented as substituting for sex & “satisfying” the need for sex in women represent one possible explanation

Golomb B A, Berg B K (February 12, 2021) Chocolate Consumption and Sex-Interest. Cureus 13(2): e13310. February 12, 2021; doi:10.7759/cureus.13310

Rolf Degen's take: Women who eat chocolate more often report less interest in sex

Abstract

Media and popular literature link chocolate and sex-interest in women, but there is little research examining their association. This cross-sectional analysis sought to address this gap by assessing the relation of chocolate-consumption frequency to self-rated interest in sex. Seven-hundred twenty-three (723) Southern California men and women, age >20, completed surveys providing chocolate-consumption frequency (Choc0, x/week) and interest in sex (rated 0-10). 

Regression (robust standard errors) examined the relationship of chocolate-consumption frequency (Choc0, x/week) to sex-interest, adjusted for potential confounders. Tests for gender and age interactions guided gender- and age-stratified analyses. The mean sex-interest was 7.0±3.0 overall; 5.7±3.1 in women and 7.4±2.8 in men. The reported chocolate frequency was 2.0±2.5x/week overall; 2.5±2.8x/week in women and 1.8±2.4x/week in men. Those who ate chocolate more frequently reported lower interest in sex. Significance was sustained with an adjustment: per-time-per-week chocolate was eaten, β=-0.11(SE=0.050), p=0.02. The gender interaction was significant (p=0.03). The gender-stratified analysis showed the effect was driven by the much stronger relation in women: full model, per time-per-week chocolate consumed, β=-0.26(SE=0.08), p=0.002. Chocolate-consumption frequency was the strongest assessed predictor of sex-interest in women. A relationship was not observed in men, though a trend was present in younger men.

Women who ate chocolate more frequently reported less interest in sex, a finding not explained by assessed potential confounders. Popular portrayals in which chocolate is represented as substituting for sex and “satisfying” the need for sex in women represent one possible explanation for these findings.

Discussion

Women who ate chocolate more frequently reported significantly less interest in sex. A qualitatively similar finding was present for analysis of combined men and women. However, the finding was particularly strong among women, and separately significant for women, for whom chocolate-consumption frequency was, indeed, the strongest assessed predictor of sex-interest. On exploratory analysis, younger adult men (under age 55) contributed somewhat to the relationship in the combined-sex sample, but the relationship of more frequent chocolate consumption to lesser sex-interest in younger men was materially weaker than the relationship in women, and the significance of the finding was attenuated with adjustments (vs strengthened in women). Older men did not share this relationship.

Fit with literature

Against a surfeit of popular allusions to a link between sex and chocolate, few studies appear to have sought to empirically assess the relation of chocolate consumption to interest in sex. We identified only one prior study that addressed something nominally similar - assessing prediction by a chocolate measure against an index of “sexual desire” in a convenience sample of women in Northern Italy [24]. Many features of the study affect statistical power and ability to see a relationship [24]: chocolate-consumption frequency was binarized (daily - yes or no) so that those eating chocolate 6x/week are categorized with those eating it never. That study’s “age-adjusted” analysis showed no significant relationship. (In fact, in their sample, younger age was associated both with more “sexual desire” and more daily chocolate consumption, producing a spurious positive association that was obviated with age-adjustment.) However, the study involved a smaller sample, and the binarized chocolate-frequency measure is expected to lose statistical benefits relative to a more continuous analysis approach. That study also did not assess, so could not adjust for, other potential confounders. Applying to our data an approximation to their analysis approach - by binarizing our chocolate measure as they did for comparison - yields their finding of a nonsignificant age-adjusted relationship in women, consistent with the expected loss of important information and statistical power by dichotomizing a more continuous predictor. Since reproducing their analysis decision - one that is associated with the expected loss of power - reproduces their null finding, that finding does not challenge our own.

Though the scientific context for our finding is limited, nonscientific representations relevant to our finding are rife and motivated the present study. Internet quote sites provide these examples: "It's not that chocolates are a substitute for love. Love is a substitute for chocolate. Chocolate is, let's face it, far more reliable than a man." - Miranda Ingram [25]; "My favorite thing in the world is a box of fine European chocolates which is, for sure, better than sex." - Alicia Silverstone [25]; “All you need is love" (where the word love is crossed out and chocolate written in) - Anonymous [26]; and "Forget love ... I'd rather fall in chocolate!" - Anonymous [25]. Instances like these reprise a theme in which chocolate is compared to (or substituted for) love and sex - with the comparison favoring chocolate - for women (albeit often with humorous intent). This depiction seems quite specific to chocolate among food products and specific to women. Our findings are consistent with but do not compel these characterizations. Indulgence in the putatively preferred comparator (chocolate) might relieve the desire for the supposedly less gratifying substitute (sex).

We do not have access to data on the frequency of sex, and interest in chocolate, to examine the converse relationship.

Mechanism

A biological underpinning for such a proposed explanation is reflected in the inference that “Chocolate gets right to the heart of sexual pleasure by increasing the brain’s level of serotonin” [6]. (Indeed, chocolate does contain phenylethylamine and stimulates biogenic amines, including serotonin and dopamine as well as catecholamines [5].) The differential effects in men vs women could be speculated to align with observations that different brain regions are activated and inhibited by chocolate consumption, and chocolate “satiety,” in women vs men [27].

Limitations

This study has limitations. It is cross-sectional: temporality is not known and causality cannot be inferred. Though it was noted that these findings are consistent with a portrayal of a chocolate-substituting-for-sex-in-women portrayal that is rife in the lay literature, they, by no means, compel that interpretation. Potential for bias and confounding are inherent to observational studies. The study did not include women of childbearing potential, and findings might not extend to this group. However, the relationship was by no means attenuated (indeed, showed a suggestion of being strengthened) for the youngest women among those assessed. The study was relatively generally sampling but did have other exclusions, and findings need not extend to excluded groups such as those with heart disease, diabetes, or cancer. The fact that questions about sex were not a central focus of the parent study, and did not figure in the recruitment process may be a relative strength, reducing participation bias based on the outcome - for a potentially sensitive topic. An additional strength is the large sample size and access to key relevant covariates, including measured testosterone, blood pressure, calorie intake, and mood.