Tuesday, September 1, 2020

Being more happy (more positive affect) was associated with heavy alcohol use

Daily associations between affect and alcohol use among adults: The importance of affective arousal. Dusti R. Jones et al. Addictive Behaviors, September 1 2020, 106623. https://doi.org/10.1016/j.addbeh.2020.106623

Objective: Little is known about whether level of affective arousal (i.e., high vs. low) is associated with alcohol use and whether this relationship differs by valence (i.e., positive vs. negative affect) among adults.

Methods. Participants were n=93 self-reported current drinkers (ages 25-65) who reported positive (PA) and negative affect (NA) seven times a day and alcohol use once a day for seven consecutive days. For each individual, mean levels of high arousal PA (e.g., excited), low arousal PA (e.g., satisfied), high arousal NA (e.g., frustrated), and low arousal NA (e.g., sad) were computed for each day.

Results. Alcohol use was reported on 30% of person-days, with an average of 2.3 drinks consumed on drinking days. Heavy episodic drinking (4+/5+ drinks for women/men) occurred on 4% of days. After covarying for age, gender, and weekday, days with higher-than-usual levels of high arousal PA were associated with a 52% increase in the odds of consuming any alcohol and a 105% increase in the odds of engaging in heavy episodic drinking. Individuals reporting more low arousal PA on average had a 77% increase in the odds of heavy episodic drinking. No significant associations between high or low arousal NA and alcohol use were found.

Conclusions. Greater PA, but not NA, was associated with heavy alcohol use at both the within- and between-person levels, perhaps attributable to social and enhancement drinking motives. Results differed by arousal, highlighting the importance of considering a wide range of affective states when examining alcohol use behavior.

Keywords: positive affectnegative affectaffective arousalalcohol use

Men’s decision to augment their masculinity via full beardedness occurs under conditions characterised by stronger inter-sexual and intra-sexual selection (competition)

Cross-Cultural Variation in Men’s Beardedness. Barnaby J. W. Dixson & Anthony J. Lee. Adaptive Human Behavior and Physiology (2020). Sep 1 2020. https://link.springer.com/article/10.1007/s40750-020-00150-4

Objectives To test whether cross-cultural variation in men’s facial hair conforms to patterns predicted by processes of inter-sexual and intra-sexual selection.

Methods Data were taken from the PEW Research Center’s World’s Muslims’ project that collected information from 14,032 men from 25 countries. An Independent Factor Analysis was used to analyse how suites of demographic factors predict men’s beardedness.

Results Analyses replicated those from past research using the PEW data, showing that beardedness was more frequent under prevailing conditions of lower health and higher economic disparity.

Conclusions These findings contribute to evidence that men’s decision to augment their masculinity via full beardedness occurs under conditions characterised by stronger inter-sexual and intra-sexual selection.

Check also Mothers are sensitive to men's beards as a potential cue of paternal investment. Barnaby J. W. Dixson, Siobhan Kennedy-Costantini, Anthony J. Lee, Nicole L. Nelson. Hormones and Behavior, Volume 113, July 2019, Pages 55-66. https://www.bipartisanalliance.com/2019/05/preferences-for-beards-when-judging.html

The belief that “my side” sees the world objectively while the “other side” sees it through the lens of its biases (the “objectivity illusion”), was strong & persistent among Trump and Clinton supporters before the election

The objectivity illusion and voter polarization in the 2016 presidential election. Michael C. Schwalbe, Geoffrey L. Cohen, and Lee D. Ross. Proceedings of the Royal Society, September 1, 2020 117 (35) 21218-21229; https://doi.org/10.1073/pnas.1912301117

Significance: Political polarization increasingly threatens democratic institutions. The belief that “my side” sees the world objectively while the “other side” sees it through the lens of its biases contributes to this political polarization and accompanying animus and distrust. This conviction, known as the “objectivity illusion,” was strong and persistent among Trump and Clinton supporters in the weeks before the 2016 presidential election. We show that the objectivity illusion predicts subsequent bias and polarization, including heightened partisanship over the presidential debates. A follow-up study showed that both groups impugned the objectivity of a putative blog author supporting the opposition candidate and saw supporters of that opposing candidate as evil.

Abstract: Two studies conducted during the 2016 presidential campaign examined the dynamics of the objectivity illusion, the belief that the views of “my side” are objective while the views of the opposing side are the product of bias. In the first, a three-stage longitudinal study spanning the presidential debates, supporters of the two candidates exhibited a large and generally symmetrical tendency to rate supporters of the candidate they personally favored as more influenced by appropriate (i.e., “normative”) considerations, and less influenced by various sources of bias than supporters of the opposing candidate. This study broke new ground by demonstrating that the degree to which partisans displayed the objectivity illusion predicted subsequent bias in their perception of debate performance and polarization in their political attitudes over time, as well as closed-mindedness and antipathy toward political adversaries. These associations, furthermore, remained significant even after controlling for baseline levels of partisanship. A second study conducted 2 d before the election showed similar perceptions of objectivity versus bias in ratings of blog authors favoring the candidate participants personally supported or opposed. These ratings were again associated with polarization and, additionally, with the willingness to characterize supporters of the opposing candidate as evil and likely to commit acts of terrorism. At a time of particular political division and distrust in America, these findings point to the exacerbating role played by the illusion of objectivity.

Keywords: intergroup conflictpolarizationcognitive biaspolitical psychology

Liking for foods high in salt and fat is associated with a lower diet quality but liking for foods high in sugar is not

Liking for foods high in salt and fat is associated with a lower diet quality but liking for foods high in sugar is not – Results from the Predise study. Elise Carbonneau et al. Food Quality and Preference, September 1 2020, 104073. https://doi.org/10.1016/j.foodqual.2020.104073

• Liking for sweet foods is not associated with Canadian Healthy Eating Index (C-HEI).
• Liking for salty foods is associated with lower consumption of healthy foods.
• Liking for salty foods is inversely associated with C-HEI in men.
• Liking for salty foods is inversely associated with C-HEI in less educated women.

Abstract: The research aimed at examining how liking for foods high in salt and fat and for foods high in sugar are associated with overall diet quality and how these associations differ according to individual characteristics (i.e., sex, age, education, income, nutrition knowledge, and energy reporting status) in French-speaking adults from the Province of Quebec, Canada. As part of the web-based cross-sectional PREDISE study, 1096 men and women completed online questionnaires. The Food Liking Questionnaire assessed reported liking for a variety of salty foods (high in salt and fat) and sweet foods (high in sugar and either high-fat or low-fat) on a scale from 1 to 9. The Canadian Healthy Eating Index (C-HEI) was computed based on data collected using 24-hour food recalls. Women (vs. men) reported lower liking for salty foods (5.97±1.34 vs. 6.58±1.16, p<0.0001) and for sweet foods (5.52±1.36 vs. 5.71±1.25, p=0.015). Multiple linear regressions showed that liking for sweet foods was not associated with C-HEI (B=-0.10, p=0.78). Given a significant sex interaction in the association between liking for salty foods and C-HEI (p interaction=0.0218), subsequent analyses were stratified by sex. Multiple linear regressions supported that liking for salty foods was more strongly inversely associated with C-HEI in men (B=-3.37, p<0.0001) than women (B=-1.46, p=0.0035). In conclusion, a strong liking for salty foods may interfere with healthy eating, especially in men. Building on these results, future studies should investigate the potential of interventions designed to improve the healthiness of food habits in individuals with strong liking for these foods.

Keywords: Food likingsalty foodssweet foodsdiet qualityHealthy Eating IndexPREDISE study

Rolf Degen summarizing... A majority of laypersons mistakenly believe that people can be trained to become highly accurate judges of truth and deception ("truth wizards")

The psychology of confessions: A comparison of expert and lay opinions. Fabiana Alceste  Timothy J. Luke  Allison D. Redlich  Johanna Hellgren  Aria D. Amrom  Saul M. Kassin. Applied Cognitive Psychology, August 16 2020. https://doi.org/10.1002/acp.3735

Summary: Despite a body of confessions research that is generally accepted in the scientific community, courts often exclude experts on the ground that such testimony would not assist the jury, which can use its common sense. To examine whether laypeople know the contents of expert testimony on confessions, we asked 151 lay participants to indicate their beliefs about 30 confession‐related statements used in a recent survey of 87 confession experts (Kassin et al., American Psychologist, 2018, 73, 63–80). Participants agreed with experts on only 10 of the 30 propositions, suggesting that much of the psychology of confessions is not common knowledge and that expert testimony can assist the trier of fact.

Testosterone administration increases the audience effect & further buttress the social status hypothesis (which posits that testosterone promotes status-seeking behaviour in a context-dependent manner)

Exogenous testosterone increases the audience effect in healthy males: Evidence for the social status hypothesis. Yin Wu et al. Proceedings of the Royal Society: Biological Sciences, July 2020. https://royalsocietypublishing.org/doi/10.1098/rspb.2020.0976

Abstract: Several studies have implicated testosterone in the modulation of altruistic behaviours instrumental to advancing social status. Independent studies have also shown that people tend to behave more altruistically when being watched (i.e. audience effect). To date, little is known about whether testosterone could modulate the audience effect. In the current study, we tested the effect of testosterone on altruistic behaviour using a donation task, wherein participants were asked to either accept or reject a monetary transfer to a charity organization accompanying a personal cost either in the presence or absence of an observer. We administered testosterone gel or placebo to healthy young men (n = 140) in a double-blind, placebo-controlled, mixed design. Our results showed that participants were more likely to accept the monetary transfer to the charity when being observed compared to when they completed the task alone. More importantly, this audience effect was amplified among people receiving testosterone versus placebo. Our findings suggest that testosterone administration increases the audience effect and further buttress the social status hypothesis, according to which testosterone promotes status-seeking behaviour in a context-dependent manner.

Electronic supplementary material: https://doi.org/10.6084/m9.figshare.c.5046800

Women show pre-copulatory mating preferences for human leucocyte antigen-dissimilar men; a possibility is that the ultimate mating bias towards HLA-dissimilar partners could occur after copulation, at the gamete level

Post-copulatory genetic matchmaking: HLA-dependent effects of cervical mucus on human sperm function. Annalaura Jokiniemi, Martina Magris, Jarmo Ritari, Liisa Kuusipalo, Tuulia Lundgren, Jukka Partanen and Jukka Kekäläinen. Proceedings of the Royal Society: Biological Sciences, August 2020. https://royalsocietypublishing.org/doi/10.1098/rspb.2020.1682

Abstract: Several studies have demonstrated that women show pre-copulatory mating preferences for human leucocyte antigen (HLA)-dissimilar men. A fascinating, yet unexplored, possibility is that the ultimate mating bias towards HLA-dissimilar partners could occur after copulation, at the gamete level. Here, we explored this possibility by investigating whether the selection towards HLA-dissimilar partners occurs in the cervical mucus. After combining sperm and cervical mucus from multiple males and females (full factorial design), we found that sperm performance (swimming velocity, hyperactivation, and viability) was strongly influenced by the male–female combination. This indicates that sperm fertilization capability may be dependent on the compatibility between cervical mucus (female) and sperm (male). We also found that sperm viability was associated with partners' HLA dissimilarity, indicating that cervical mucus may selectively facilitate later gamete fusion between immunogenetically compatible partners. Together, these results provide novel insights into the female-mediated sperm selection (cryptic female choice) in humans and indicate that processes occurring after copulation may contribute to the mating bias towards HLA-dissimilar partners. Finally, by showing that sperm performance in cervical mucus is influenced by partners' genetic compatibility, the present findings may promote a deeper understanding of infertility.

4. Discussion

Our results show that along with sperm intrinsic quality (male effect) and cervical mucus identity (female effect), sperm performance was also strongly dependent on male–female combination (interaction), explaining 8.5–32.3% of the total variation in measured sperm traits. In other words, females had a stronger effect on the sperm of some males than the others. We also observed that both the number of different HLA alleles and the Grantham pairwise amino acid distance of HLA alleles affected sperm viability: sperm had higher survival rates in HLA-dissimilar male–female combinations than in more similar combinations. Conversely, we found that HLA-allele sharing did not affect sperm motility, but the Grantham distance was negatively associated with sperm swimming velocity and hyperactivation in one of the three time points (180 min). In other words, sperm motility was higher in male–female combinations that had low HLA amino acidic divergence in comparison to more dissimilar combinations. However, the observed effect was male-dependent, indicating that the effect of the Grantham distance on sperm motility varies across males. None of the measured sperm traits was associated with male–female genome-wide similarity. Although all the male subjects were diagnosed as normozoospermic it is possible that reproductive physiology of the study subjects may partly differ from that of the average male and/or female population. Consequently, some caution should be applied to generalize our findings and future research should ideally aim to test whether the same mechanisms are widespread in the human population.
The female reproductive tract allows only a minute subset of spermatozoa to reach the site of fertilization [49,75,76], but the mechanisms and function of this stringent sperm selection have remained ambiguous. It has been suggested that the functional incompatibility between cervical mucus and sperm could play an important role in the process [62,66], but to the best of our knowledge none of the earlier studies have experimentally tested this possibility. The present results demonstrate that the chemical composition of the cervical mucus may selectively maintain sperm viability of HLA-dissimilar males, indicating that cervical mucus could mediate post-copulatory choice towards the sperm of immunologically compatible males. Furthermore, given that sperm performance in cervical mucus predicts fertilization success [62], these results raise the novel possibility that immunological compatibility between sperm and cervical mucus plays an important role in determining the reproductive success of the partners. While previous studies have reported an effect of MHC-dissimilarity on egg-sperm fusion [6,1719,21], to our knowledge, this is the first study to show that MHC-based cryptic female choice could be mediated by fluids of the female reproductive tract in mammals.
Earlier studies have demonstrated that cervical mucus is capable of conserving sperm function [62] and it has been hypothesized that cervical crypts could serve as sperm reservoirs [77], where sperm motility is restrained to enhance longevity, such as in the sperm storage sites of the oviduct [78,79]. Besides demonstrating that cervical mucus likely preserves sperm viability of HLA-dissimilar males, we also found evidence that cervical mucus may simultaneously restrict sperm motility of these males. This could indicate that one key function of cervical mucus is to selectively store the sperm of immunologically compatible males, possibly for later use in fertilization. Alternatively, our results raise the intriguing possibility that females (via cervical mucus) may reduce the survival of sperm of (overly) HLA-similar males on the one hand and slow down the sperm of (overly) HLA-dissimilar ones on the other. Such a search for intermediate MHC dissimilarity may facilitate ‘production' of intermediately heterozygous offspring at MHC loci, which, according to the optimal MHC-heterozygosity hypothesis, may have better immunocompetence than more heterozygous individuals [80]. In fact, while highly heterozygous individuals at MHC loci are able to present more antigens to the immune system, they are likely to have smaller T-cell repertoires following thymic selection [80]. Supporting the optimal heterozygosity hypothesis, Jacob et al. [81] showed that women prefer the body odour of men with whom they share few HLA alleles over the more similar and dissimilar men [36]. However, since observed sperm motility associations were present only at one time point and were not consistent across males, further studies are required to investigate the relative importance of these alternative functions of cervical mucus. Furthermore, since performed cervical mucus dilution likely altered sperm motility patterns, we encourage future studies to confirm whether our results can be replicated in undiluted cervical mucus to fully account for its natural viscoelastic features.
The observed effects of partners' HLA dissimilarity on sperm function could potentially arise at least through two evolutionary mechanisms. First, as highlighted above, cervical mucus -mediated selection towards HLA-dissimilar males may represent an evolutionary strategy that ensures the ‘production' of offspring that have broad (or optimal) antigen recognition capability and thus better ability to fight against infections [82]. Supporting this possibility, pathogens have been widely assumed to be the strongest selective agent in human evolution (e.g. [9]). Alternatively, it is possible that HLA-associated sperm preferences represent a gamete-level inbreeding avoidance mechanism that prevents mating between close relatives [10]. In the present study, however, we found that overall (genome-wide) genetic similarity was not associated with sperm performance, indicating that observed findings are more likely to be a direct consequence of HLA-dependent sperm selection, instead of inbreeding avoidance based on HLA-independent cues. Although detailed molecular-level mechanisms behind our findings remain to be described, we envisage that sperm surface HLA molecules and/or HLA-linked olfactory receptors [83] may play an important role in the demonstrated sperm selection process.
Besides clarifying the mechanistic basis of female-induced sperm selection in humans, our findings may have novel implications for the deeper understanding of infertility and for the development of new contraceptives. Infertility affects about 15% of couples globally and currently remains unexplained in 30–40% of cases [84]. Furthermore, a reliable diagnosis of infertility is extremely challenging, and the accuracy of diagnoses is low when compared to several other areas of medicine [85,86]. According to current clinical practice, infertility problems are partitioned into male- and female-derived pathological factors and are thus thought to represent a disease of the reproductive system [87]. Our results indicate that this may represent an overly simplistic view, since it does not consider the fact that some male–female (or their gamete) combinations may be immunologically more compatible than others. Consequently, gamete-level incompatibility may reduce the probability of conception and may help to understand fertilization problems, especially in couples that are diagnosed with unexplained infertility.
In conclusion, our results show that chemical factors in the cervical mucus preferentially conserve sperm viability (and possibly constrain sperm motility) of HLA-dissimilar males. This indicates that one of the key functions of cervical mucus may be to selectively facilitate gamete fusion between immunogenetically compatible partners and this way facilitate optimization of offspring immunocompetence. Immunological mechanisms of sperm selection have remained virtually unexplored in mammals and internally fertilizing species, in general. The present results provide novel insights into MHC-based post-copulatory sperm selection in humans and may be potentially applied to many other species. Furthermore, a more pervasive integration of the demonstrated ‘gamete compatibility' concept into current infertility diagnostic guidelines may facilitate development of more personalized infertility diagnostics and increase accuracy of the diagnoses.