Sunday, July 25, 2021

Greece: Gay people were not less likely than people of other sexual orientations to be in a relationship; gay men but not women experienced longer spells of singlehood than people of other sexual orientations

The effect of sexual orientation on singlehood: Evidence from the Greek cultural context. Menelaos Apostolou. Personality and Individual Differences, Volume 183, December 2021, 111150. https://doi.org/10.1016/j.paid.2021.111150

Highlights

• Finds that, homosexual people were not less likely than people of other sexual orientations to be in a relationship.

• Finds that, homosexual people were considerably less likely to be married than people of other sexual orientations.

• Finds that, homosexual men but not women experienced longer spells of singlehood than people of other sexual orientations.

Abstract: The social stigma attached to same-sex attraction, along with the limited availability of same-sex outlets, are likely to cause difficulties to homosexual people in attracting intimate partners. Based on this reasoning, the current study aimed to test the hypothesis that homosexual people would be more likely to be involuntarily single, and would experience longer spells of singlehood than people of other sexual orientations. Evidence from a sample of 10,939 Greek-speaking participants, indicated that homosexual people were not less likely than people of other sexual orientations to be in a relationship than involuntarily single. However, homosexual people were considerably less likely to be married than people of other sexual orientations, with the effect being more pronounce for men than for women. In addition, male homosexuals experienced longer spells of singlehood than men of other sexual orientations, but no such effect was found for women.


Keywords: SinglehoodInvoluntary singlehoodSexual orientationHomosexuality


COVID-19: Across 17 countries with lower fluctuations in births, the number of births fell on average by more than 5% in Nov & Dec 2020 & 8.9% in Jan 21, YoY; Spain births plummeted by 20% in Dec 20 and Jan 21

Sobotka, Tomas, Aiva Jasilioniene, Ainhoa A. Galarza, Kryštof Zeman, Laszlo Nemeth, and Dmitri Jdanov. 2021. “Baby Bust in the Wake of the COVID-19 Pandemic? First Results from the New STFF Data Series.” SocArXiv. March 24. doi:10.31235/osf.io/mvy62

Abstract: Past evidence on fertility responses to external shocks, including economic recessions and the outbreaks of infectious diseases, show that people often put their childbearing plans on hold in uncertain times. We study the most recent data on monthly birth trends to analyse the initial fertility responses to the outbreak of the COVID-19 pandemic. Our research, based on new Short-Term Fertility Fluctuations (STFF) data series (https://www.humanfertility.org/cgi-bin/stff.php), embedded in the Human Fertility Database (HFD), shows the initial signs of the expected “birth recession”. Monthly number of births in many countries fell sharply between October 2020 and the most recent month observed, often bringing about a clear reversal of the previous trend. Across 17 countries with lower fluctuations in births, the number of births fell on average by 5.1% in November 2020, 6.5% in December 2020 and 8.9% in January 2021 when compared with the same month of the previous year. Spain sustained the sharpest drop in the number of births among the analysed countries, with the number of births plummeting by 20% in December 2020 and January 2021. The combined effect of rising mortality and falling birth rates is disrupting the balance of births and deaths in many countries, pushing natural population increase to record low levels in 2020 and 2021.



Additional wealth and unearned income effects: An extra dollar of unearned income in a given period reduces pre-tax labor earnings by about 50 cents, decreases total labor taxes by 10 c, & increases consumption by 60 c

How Americans Respond to Idiosyncratic and Exogenous Changes in Household Wealth and Unearned Income. Mikhail Golosov, Michael Graber, Magne Mogstad, and David Novgorodsky. Becker Friedman Institute, Working Paper 2021-76. Jul 2021.  https://bfi.uchicago.edu/wp-content/uploads/2021/06/BFI_WP_2021-76.pdf

Abstract: We study how Americans respond to idiosyncratic and exogenous changes in household wealth and unearned income. Our analyses combine administrative data on U.S. lottery winners with an event study design that exploits variation in the timing of lottery wins. Our first contribution is to estimate the earnings responses to these windfall gains, finding significant and sizable wealth and income effects. On average, an extra dollar of unearned income in a given period reduces pre-tax labor earnings by about 50 cents, decreases total labor taxes by 10 cents, and increases consumption by 60 cents. These effects are heterogeneous across the income distribution, with households in higher quartiles of the income distribution reducing their earnings by a larger amount. Our second contribution is to develop and apply a rich life-cycle model in which heterogeneous households face non-linear taxes and make earnings choices along both intensive and extensive margins. By mapping this model to our estimated earnings responses, we obtain informative bounds on the impacts of two policy reforms: an introduction of UBI and an increase in top marginal tax rates. Our last contribution is to study how additional wealth and unearned income affect a wide range of behavior, including geographic mobility and neighborhood choice, retirement decisions and labor market exit, family formation and dissolution, entry into entrepreneurship, and job-to-job mobility.

JEL Codes: D15, J22, H21, H31, H53

Keywords: income effects; labor supply elasticities; lottery winning; taxation; universal basic income; wealth effects


Historical language records reveal a surge of cognitive distortions in recent decades: Maybe recent socioeconomic changes, new technology, and social media are associated with a surge of those distortions

Historical language records reveal a surge of cognitive distortions in recent decades. Johan Bollen et al. Proceedings of the National Academy of Sciences, July 27, 2021 118 (30) e2102061118; https://doi.org/10.1073/pnas.2102061118

Significance: Can entire societies become more or less depressed over time? Here, we look for the historical traces of cognitive distortions, thinking patterns that are strongly associated with internalizing disorders such as depression and anxiety, in millions of books published over the course of the last two centuries in English, Spanish, and German. We find a pronounced “hockey stick” pattern: Over the past two decades the textual analogs of cognitive distortions surged well above historical levels, including those of World War I and II, after declining or stabilizing for most of the 20th century. Our results point to the possibility that recent socioeconomic changes, new technology, and social media are associated with a surge of cognitive distortions.

Abstract: Individuals with depression are prone to maladaptive patterns of thinking, known as cognitive distortions, whereby they think about themselves, the world, and the future in overly negative and inaccurate ways. These distortions are associated with marked changes in an individual’s mood, behavior, and language. We hypothesize that societies can undergo similar changes in their collective psychology that are reflected in historical records of language use. Here, we investigate the prevalence of textual markers of cognitive distortions in over 14 million books for the past 125 y and observe a surge of their prevalence since the 1980s, to levels exceeding those of the Great Depression and both World Wars. This pattern does not seem to be driven by changes in word meaning, publishing and writing standards, or the Google Books sample. Our results suggest a recent societal shift toward language associated with cognitive distortions and internalizing disorders.

Keywords: cognitive distortionsinternalizing disordershistorical language analysis

Check also Individuals with depression express more distorted thinking on social media. Krishna C. Bathina, Marijn ten Thij, Lorenzo Lorenzo-Luaces, Lauren A. Rutter & Johan Bollen. Nature Human Behaviour, February 11 2021. https://www.bipartisanalliance.com/2021/02/individuals-with-depression-express.html


“You don’t believe in God? You ain’t Black”: Identifying as atheist elicits identity denial from Black ingroup members

Howard, S., Kennedy, K. C., & Vine, K. T. (2021). “You don’t believe in God? You ain’t Black”: Identifying as atheist elicits identity denial from Black ingroup members. Cultural Diversity and Ethnic Minority Psychology, Jul 2021. https://doi.org/10.1037/cdp0000397

Abstract: Objective: Anecdotal narratives and recent qualitative research with Black atheists document experiences of racial identity denial from the target’s perspective. However, no research to date has examined whether Black perceivers perceive Black atheists as being weakly identified with their race. Because belief in God is often inextricably linked with Black racial identity in the Black community, we hypothesized that Black atheists would be perceived as less Black than nonatheists.

Method: Black/African American adults (n = 343) were randomly assigned to view one of three Black individual’s social networking profiles (i.e., a Christian, an atheist, and religion not explicitly mentioned). After, they reported their perceptions of the targets’ perceived racial identity and trustworthiness.

Results: Black participants, regardless of how strongly they identified racially, perceived a Black Atheist as less racially identified than a Black Christian or someone whose religious affiliation was unknown. Additionally, a Black atheist was perceived as less trustworthy than a Black Christian.

Conclusions: Black atheists experience general anti-atheist bias (e.g., perceived as untrustworthy), as well as unique anti-atheist bias in the form of racial identity denial. These findings extend previous research on identity denial and intragroup dynamics and advance our understanding of the relationship between religious identification and racial identity denial within the Black community.


Sexual Orientation, Sexual Arousal, and Finger Length Ratios in Women

Sexual Orientation, Sexual Arousal, and Finger Length Ratios in Women. Luke Holmes, Tuesday M. Watts-Overall, Erlend Slettevold, Dragos C. Gruia, Jamie Raines & Gerulf Rieger. Archives of Sexual Behavior, Jul 23 2021. https://link.springer.com/article/10.1007%2Fs10508-021-02095-5

Abstract: In general, women show physiological sexual arousal to both sexes. However, compared with heterosexual women, homosexual women are more aroused to their preferred sex, a pattern typically found in men. We hypothesized that homosexual women’s male-typical arousal is due to their sex-atypical masculinization during prenatal development. We measured the sexual responses of 199 women (including 67 homosexual women) via their genital arousal and pupil dilation to female and male sexual stimuli. Our main marker of masculinization was the ratio of the index to ring finger, which we expected to be lower (a masculine pattern) in homosexual women due to increased levels of prenatal androgens. We further measured observer- and self-ratings of psychological masculinity–femininity as possible proxies of prenatal androgenization. Homosexual women responded more strongly to female stimuli than male stimuli and therefore had more male-typical sexual responses than heterosexual women. However, they did not have more male-typical digit ratios, even though this difference became stronger if analyses were restricted to white participants. Still, variation in women's digit ratios did not account for the link between their sexual orientation and their male-typical sexual responses. Furthermore, homosexual women reported and displayed more masculinity than heterosexual women, but their masculinity was not associated with their male-typical sexual arousal. Thus, women’s sexual and behavioral traits, and potential anatomical traits, are possibly masculinized at different stages of gestation.

Discussion

The present data confirmed that homosexual women had more male-typical sexual arousal patterns than heterosexual women, as indicated by both their genital arousal and their pupil dilation. However, there was no evidence that they had more male-typical digit ratios, or that digit ratios mediated the relationship between women’s sexual orientation and their male-typical sexual arousal patterns. Moreover, even though homosexual women were more masculine than heterosexual women in their self-reports or via observer ratings, this pattern, too, did not explain their male-typical arousal patterns.

The finding that homosexual women had stronger responses to their preferred sex than heterosexual women is consistent with previous research both for genital arousal and pupil dilation (Chivers et al., 20042007; Rieger et al., 20152016). However, the finding that 2D:4D was not significantly lower in homosexual women than heterosexual women is puzzling, as it was confirmed previously in a meta-analysis (Grimbos et al., 2010). This may have been due to methodological reasons: Although between-rater reliability was high, and computer-assisted measurement techniques, such as those employed in the current study, have been shown to have the highest reliability compared to other methods of measuring 2D:4D (Allaway et al., 2009), we cannot say with certainty that our measure was valid.

Indeed, there is an ongoing debate about the utility of 2D:4D: Although it is regarded as a valid measure with respect to sex differences and female sexual orientation differences, it is also the case that there is much variability in this measure across individuals, and findings only apply on aggregate and do not apply to single people (Swift-Gallant et al., 2020). Furthermore, the aforementioned meta-analysis suggested a publication bias in reported relationships of sexual orientation with 2D:4D (Grimbos et al., 2010), and the true effect could therefore be smaller than usually published. In the present data, the strongest linear relationship of sexual orientation with 2D:4D was r (or β) = − 0.12 in the right hand. With this effect, post hoc power analyses indicated a minimum sample of 542 women for it to be significant. If our a priori sample size estimate had returned such a large number, we would have considered it an unreasonable goal for a laboratory-based study like ours.

Another possible explanation for the present null finding with respect to 2D:4D is the ethnic makeup of the sample. We did not factor this into planning the present study because the meta-analysis pointed to an ethnicity effect only in men and not in women (Grimbos et al., 2010), although other research has found an influence of ethnicity on 2D:4D in women (Lippa, 2003). Indeed, excluding all non-Caucasian participants from the present sample made the association between 2D:4D and sexual orientation stronger (although still nonsignificant) in both hands (Fig. 4). Thus, future research measuring the relationship between 2D:4D and sexual orientation may wish to either employ a racially homogenous participant sample, or recruit enough participants that per-race comparisons are feasible. Note that even within the white sample, 2D:4D did not appear to explain (mediate) any relationship of women's sexual orientation with their sexual response patterns.

It is impossible to draw any conclusions from the present data about whether the relationship between 2D:4D and sexual orientation mediates the relationship between sexual orientation and sexual responses, simply because 2D:4D in itself did not relate to sexual orientation. With regard to masculinity–femininity, if anything, statistically controlling for any of the three masculinity–femininity variables made the correspondence of women’s sexual orientation with their male-typical sexual arousal stronger. This pattern—a strengthening of the effect of sexual orientation on sexual response when measures of behavioral masculinity are statistically controlled for—has been previously noted (Rieger et al., 2016). In combination with present findings, it appears unlikely that it was previously a chance finding.

If one assumed for a moment that the present findings are accurate, what could be their reasons? For females, it is possible that there exist several “sensitive periods” of masculinization during prenatal development, and that these periods differ for different traits (McCarthy et al., 2018; Xu et al., 2019). At least in non-human primates, exposure to testosterone at different stages of gestation may masculinize sexual behaviors independently from non-sexual behaviors (Goy et al., 1988). Specifically, Goy et al. reported that female rhesus macaques exposed to testosterone during their prenatal development had different behavioral outcomes depending on the timing, with those exposed early in gestation displaying male-typical sexual behaviors (e.g., mounting other females) and those exposed late in gestation displaying male-typical non-sexual behaviors (e.g., rough play). It is possible that behavioral traits and sexual arousal patterns are masculinized at different stages of development in humans also, and thus, are not necessarily interlinked within individuals—for example, those who have male-typical arousal may not have male-typical gender-related behaviors and vice versa.

A final point concerns bisexual women, who were intermediate between heterosexual and homosexual women in their sexual arousal and masculinity–femininity, but were significantly more feminine in their 2D:4D. One hypothesis is that due to intermediate dosages of genetic or prenatal hormonal influences, bisexual individuals, who could be considered to have sexual orientations between heterosexual and homosexual, also fall intermediate with respect to correlates of sexual orientation (Rieger et al., 2020). Thus, regarding bisexual women's 2D:4D, we assumed that they could also be intermediate between heterosexual and homosexual women on this measure. Contrary to this assumption, bisexual women had more feminine 2D:4D than both heterosexual and homosexual women (Table 1). It has been proposed that personality differences between homosexual and heterosexual women may be caused by exposure to androgens during prenatal development, whereas the distinct personality traits of bisexual individuals (e.g., higher sociosexuality compared to heterosexual and homosexual) may be a correlate of their higher levels of postnatal androgens (Lippa, 2020). If the present findings are valid, they would suggest that bisexual women also differ from heterosexual and homosexual women with respect to prenatal androgenization, but this would imply that they have been less masculinized than other groups, and we cannot offer an explanation for why this would be the case.

In sum, the findings of the present research suggest that there is no link between the male-typical sexual responses of homosexual women and putative markers of prenatal androgenization. Other purported markers of androgen exposure may reveal a different pattern than the one reported here. Such markers include the distance between the anus and the genitalia (Barrett et al., 2018) and otoacoustic emissions, which are tiny sounds emitted by the inner ear (McFadden & Pasanen, 1998). Another avenue for future research would involve individuals with conditions affecting the availability of androgens, or their sensitivity to them. To our knowledge, no studies to date investigated the arousal patterns of women with CAH. If androgen exposure does indeed impact sexual responses—and given the apparent impact of excessive androgens on the sexual orientation of women with CAH (Meyer-Bahlburg et al., 2008; Zucker et al., 1996)—women with CAH may show male-typical specificity in their sexual arousal.

Saturday, July 24, 2021

In the U.K., he noted "a tendency to admire authoritarian China among scientists that surprised some people;" "scientists take a somewhat top-down view of the political world," contrary to bottom-up Evolution

How science lost the public’s trust. Tunku Varadarajan. The Wall Street Journal, July 24 2021. https://www.wsj.com/articles/covid-china-media-lab-leak-climate-ridley-biden-censorship-coronavirus-11627049477

From climate to Covid, politics and hubris have disconnected scientific institutions from the philosophy and method that ought to guide them.

‘Science” has become a political catchword. “I believe in science,” Joe Biden tweeted six days before he was elected president. “ Donald Trump doesn’t. It’s that simple, folks.” 

But what does it mean to believe in science? The British science writer Matt Ridley draws a pointed distinction between “science as a philosophy” and “science as an institution.” The former grows out of the Enlightenment, which Mr. Ridley defines as “the primacy of rational and objective reasoning.” The latter, like all human institutions, is erratic, prone to falling well short of its stated principles. Mr. Ridley says the Covid pandemic has “thrown into sharp relief the disconnect between science as a philosophy and science as an institution.”

Mr. Ridley, 63, describes himself as a “science critic, which is a profession that doesn’t really exist.” He likens his vocation to that of an art critic and dismisses most other science writers as “cheerleaders.” That somewhat lofty attitude seems fitting for a hereditary English peer. As the fifth Viscount Ridley, he’s a member of Britain’s House of Lords, [...]

[...] With the Canadian molecular biologist Alina Chan, he’s finishing a book called “Viral: The Search for the Origin of Covid-19,” to be published in November.

It will likely make its authors unwelcome in China. As Mr. Ridley worked on the book, he says, it became “horribly clear” that Chinese scientists are “not free to explain and reveal everything they’ve been doing with bat viruses.”

That information has to be “dug out” by outsiders like him and Ms. Chan. The Chinese authorities, he says, ordered all scientists to send their results relevant to the virus for approval by the government before other scientists or international agencies could vet them: “That is shocking in the aftermath of a lethal pandemic that has killed millions and devastated the world.”

Mr. Ridley notes that the question of Covid’s origin has “mostly been tackled by people outside the mainstream scientific establishment.” People inside not only have been “disappointingly incurious” but have tried to shut down the inquiry “to protect the reputation of science as an institution.” The most obvious reason for this resistance: If Covid leaked from a lab, and especially if it developed there, “science finds itself in the dock.”

Other factors have been at play as well. Scientists are as sensitive as other elites to charges of racism, which the Communist Party used to evade questions about specifically Chinese practices “such as the trade in wildlife for food or lab experiments on bat coronaviruses in the city of Wuhan.”

Scientists are a global guild, and the Western scientific community has “come to have a close relationship with, and even a reliance on, China.” Scientific journals derive considerable “income and input” from China, and Western universities rely on Chinese students and researchers for tuition revenue and manpower. All that, Mr. Ridley says, “may have to change in the wake of the pandemic.”

In the U.K., he has also noted “a tendency to admire authoritarian China among scientists that surprised some people.” It didn’t surprise Mr. Ridley. “I’ve noticed for years,” he says, “that scientists take a somewhat top-down view of the political world, which is odd if you think about how beautifully bottom-up the evolutionary view of the natural world is.”

He asks: “If you think biological complexity can come about through unplanned emergence and not need an intelligent designer, then why would you think human society needs an ‘intelligent government’?” Science as an institution has “a naive belief that if only scientists were in charge, they would run the world well.” Perhaps that’s what politicians mean when they declare that they “believe in science.” As we’ve seen during the pandemic, science can be a source of power.

But there’s a “tension between scientists wanting to present a unified and authoritative voice,” on the one hand, and science-as-philosophy, which is obligated to “remain open-minded and be prepared to change its mind.” Mr. Ridley fears “that the pandemic has, for the first time, seriously politicized epidemiology.” It’s partly “the fault of outside commentators” who hustle scientists in political directions. “I think it’s also the fault of epidemiologists themselves, deliberately publishing things that fit with their political prejudices or ignoring things that don’t.”

Epidemiologists are divided between those who want more lockdowns and those who think that approach wasn’t effective and might have been counterproductive. Mr. Ridley sides with the latter camp, and he’s dismissive of the alarmist modeling that led to lockdowns in the first place. “The modeling of where the pandemic might go,” he says, “presents itself as an entirely apolitical project.

But there have been too many cases of epidemiologists presenting models based on rather extreme assumption.”

One motivation: Pessimism sells. “You don’t get blamed for being too pessimistic, but you do get attention. It’s like climate science. Modeled forecasts of a future that is scary is much more likely to get you on television.” Mr. Ridley invokes Michael Crichton, the late science-fiction novelist, who hated the tendency to describe the outcomes of models in words that imply they are the “results” of an experiment. That frames speculation as if it were proof.

Climate science is already far down the road to politicization. “Twenty or 30 years ago,” Mr. Ridley says, “you could study how the ice ages happened and discuss competing theories without being at all political about it.” Now it’s very hard to have a conversation on the subject “without people trying to interpret it through a political lens.”

[...]

The politicization of science leads to a loss of confidence in science as an institution. The distrust may be justified but leaves a vacuum, often filled by a “much more superstitious approach to knowledge.” To such superstition Mr. Ridley attributes public resistance to technologies such as genetically modified food, nuclear power—and vaccines.

If you spurn Covid-19 vaccination, Mr. Ridley says he would “fervently argue” that it is “the lesser of two risks, at least for adults.” We have “ample data to show that—for this vaccine, and for others, going back centuries.” He calls vaccination “probably the most massive and incredible benefit of scientific knowledge.” Yet it’s “counterintuitive and difficult to understand,” which may explain why its advocates have been vilified through the centuries.

He cites the example of Mary Wortley Montagu, a British aristocrat, who pushed for smallpox inoculation in Britain after witnessing its administration in Ottoman Turkey in the early 18th century. She was viciously pilloried, he says, as was Zabdiel Boylston, a celebrated Boston doctor who inoculated residents against smallpox during a smallpox outbreak in 1721.

Vaccines have been central to the question of “misinformation” and the White House’s pressure campaign against social media to censor it. Mr. Ridley worries about the opposite problem: that social media “is complicit in enforcing conformity.” It does this “through ‘fact checking,’ mob pile-ons, and direct censorship, now explicitly at the behest of the Biden administration.” He points out that Facebook and Wikipedia long banned any mention of the possibility that the virus leaked from a Wuhan laboratory.

“Conformity,” Mr. Ridley says, “is the enemy of scientific progress, which depends on disagreement and challenge. Science is the belief in the ignorance of experts, as [the physicist Richard] Feynman put it.” Mr. Ridley reserves his bluntest criticism for “science as a profession,” which he says has become “rather off-puttingly arrogant and political, permeated by motivated reasoning and confirmation bias.” Increasing numbers of scientists “seem to fall prey to groupthink, and the process of peer-reviewing and publishing allows dogmatic gate-keeping to get in the way of new ideas and open-minded challenge.”

 The World Health Organization is a particular offender: “We had a dozen Western scientists go to China in February and team up with a dozen Chinese scientists under the auspices of the WHO.” At a subsequent press conference they pronounced the lab-leak theory “extremely unlikely.” The organization also ignored Taiwanese cries for help with Covid-19 in January 2020.

“The Taiwanese said, ‘We’re picking up signs that this is a human-to-human transmission that threatens a major epidemic. Please, will you investigate?’ And the WHO basically said, ‘You’re from Taiwan. We’re not allowed to talk to you.’ ”

 He notes that WHO’s primary task is forestalling pandemics. Yet in 2015 it “put out a statement saying that the greatest threat to human health in the 21st century is climate change. Now that, to me, suggests an organization not focused on the day job.”

In Mr. Ridley’s view, the scientific establishment has always had a tendency “to turn into a church, enforcing obedience to the latest dogma and expelling heretics and blasphemers.” This tendency was previously kept in check by the fragmented nature of the scientific enterprise: Prof. A at one university built his career by saying that Prof. B’s ideas somewhere else were wrong. In the age of social media, however, “the space for heterodoxy is evaporating.” So those who believe in science as philosophy are increasingly estranged from science as an institution. It’s sure to be a costly divorce.

Mr. Varadarajan, a Journal contributor, is a fellow at the American Enterprise Institute and at New York University’s Classical Liberal Institute.

In general, pornography use trended downward over the pandemic, for both men and women; problematic pornography use trended downward for men and remained low and unchanged in women

Porndemic? A Longitudinal Study of Pornography Use Before and During the COVID-19 Pandemic in a Nationally Representative Sample of Americans. Joshua B. Grubbs, Samuel L. Perry, Jennifer T. Grant Weinandy & Shane W. Kraus. Archives of Sexual Behavior, Jul 19 2021. https://link.springer.com/article/10.1007%2Fs10508-021-02077-7

Abstract: Of the many changes in daily life brought about by the COVID-19 pandemic, social distancing efforts and governmentally mandated lockdowns were among the most drastic. Coinciding with these changes, popular pornography websites made some previously premium content available for free, spurring dramatic increases in traffic to these websites. This increase in time spent at home and reported increases in traffic to specific pornographic websites led to some speculation that pornography use might generally increase over the course of the pandemic and that problematic use might also increase. To test these speculations and quantify the effects of the pandemic and its associated restrictions on social behaviors on pornography use, we analyzed data from a longitudinal sample of American adults. Baseline, nationally representative data were collected in August 2019 via YouGov (N = 2518). Subsequent data were collected in February 2020 (n = 1677), May 2020 (n = 1533), August 2020 (n = 1470), and October 2020 (n = 1269). Results indicated that, in May 2020, immediately following the height of the first wave of pandemic-related lockdowns, more people reported past-month pornography use than at other follow-up time points, but less did so than at baseline. Among those who reported use in May 2020, only 14% reported increases in use since the start of the pandemic, and their use returned to levels similar to all other users by August 2020. In general, pornography use trended downward over the pandemic, for both men and women. Problematic pornography use trended downward for men and remained low and unchanged in women. Collectively, these results suggest that many fears about pornography use during pandemic-related lockdowns were largely not supported by available data.

Discussion

At the outset of this work, we sought to examine whether or not there was evidence that pornography use had increased in response to the COVID-19 pandemic and associated restrictions on social behavior. Using a longitudinal study that started with a nationally representative sample of adults in the U.S., we examined the extent to which pornography viewing frequency and PPU changed from August 2019 to October 2020. Below, we summarize our findings and discuss the implications of the present work in the context of the ongoing COVID-19 pandemic and associated lockdowns.

Pornography in the Pandemic

As we noted earlier in this work, the world’s largest pornographic website made claims of increased pornography use at the outset of the COVID-19 pandemic during the height of the first wave of lockdowns and stay-at-home orders (Pornhub Insights, 2020). These increases in pornography use occurred in tandem with this same website offering a range of incentives for increased use. Similarly, analyses of internet search data suggested that interest in pornography peaked during the early stages of the pandemic (Zattoni et al., 2020). Collectively, this led to speculation in popular media (Grubbs, 2020) and peer-reviewed journals (Király et al., 2020; Mestre-Bach et al., 2020; Sinclair et al., 2020) about the possibility for pornography use to increase over the course of the pandemic. However, the present results indicate that, overall, changes seen in pornography viewing during the first several months of the pandemic were generally minimal and impermanent for both men and women.

Over the course of data collection, we found that the majority (86%) of our sample reported either decreases or consistency in their pornography use during the height of pandemic-related lockdowns (i.e., May 2020). It is important to note that a minority of our sample (5% of our May 2020, follow-up sample; corresponding with 14% of those who viewed pornography within one month of our May 2020, wave; 14.6% of men, 13.7% of women) did report increases in pornography use during the first COVID-19-related lockdowns. However, even for this group, by August 2020 and continuing into October 2020, their use had returned to levels indistinguishable from levels of those who reported decreases or that their use had stayed the same. Although a greater percentage of participants reported viewing pornography within the past month in May 2020 than did so at any other follow-up (38%), the percentages of people reporting past-month use in August 2020 (23%) and October 2020 (20.6%) were substantially lower than prior waves. Moreover, though May 2020 demonstrated the highest pornography use of any follow-up, rates of use were still lower than baseline rates in August 2019. In short, although it seems that, in May 2020, more people did indeed view pornography within the past month than at other follow-up points, this is better characterized as slight deviation from an otherwise clear downward trend.

Results from our LGC analyses generally support the above findings. Across five time points, we found no evidence that general symptoms of depression and anxiety trended either downward or upward, but rather remained stable over the course of our study. We found clear evidence that pornography use frequency trended toward less use over the course of the pandemic for both men and women. With regard to self-reported PPU, we found that it trended downward for men. For women, PPU neither increased nor decreased, on average. That is, PPU among women remained low and consistently flat without any fluctuations over the five time points.

In sum, although concerns were raised that pornography viewing (and possibly PPU) could increase during the early part of the pandemic (Grubbs, 2020; Turak, 2020), our results do not fully support this conclusion. That is, the above findings suggest that pornography use generally decreased for both men and women over the 15 months of data collection, and, even among those who experienced initial increases in pornography use, such increases were temporary. The general trends for both pornography use and PPU were downward, particularly for men, with little change in PPU for women who started with already low levels of PPU.

Implications

Despite the public-facing concerns that many public outlets, activists, and even some academic researchers shared, there is little evidence to support the notion that widespread increases in pornography use were a problem among U.S. adults during the early stages of the COVID-19 pandemic and its associated lockdowns. Although it is certainly possible that individual experiences may vary (i.e., some people may have experienced increased PPU), the general trend was for both pornography use and self-reported PPU to decrease over the course of this study. We suspect that the novelty effects of viewing pornography, even with a premium subscription offered to entice new viewers by Pornhub, likely wore off as people adjusted to new routines and allocated their time to working from home or taking on new demands caused by the pandemic (e.g., online schooling for children, caring for family members). Perhaps more simply, as promotional offers of free premium content expired, people may have simply stopped consuming as much pornography. Additionally, as the initial lockdown periods expired and the weather became more amenable to outdoor activities across the U.S., it is also possible that people were spending less time alone at home. Such conjecture is consistent with the previously discussed literature noting that boredom often motivates pornography use and suggests that, as people found alternate ways to spend their time, boredom-motivated pornography use likely decreased.

We have largely framed the results of the present work in the context of mandatory lockdowns, rather than in the context of the pandemic itself. Specifically, though lockdowns and restrictions have largely eased in the U.S. since their initial peak in April and May 2020, the SARS-CoV-2 virus has spread at a much greater rate in the times since those lockdowns expired. Accordingly, it is important to note that the trend of pornography use decreasing over the course of this work has occurred as the objective markers of the pandemic itself have increased. This suggests that, whereas lockdowns, restrictions, and stay-at-home orders in the Spring of 2020 did coincide to more people reporting pornography use in May of 2020 than at any other follow-up, pornography use has trended downward even as the spread of the SARS-CoV-2 has trended upward. In short, although speculative, the effects of the pandemic and associated social distancing measures on pornography use seem to have occurred as a result of lockdown efforts (i.e., more boredom, increased free time), rather than responses to the virus itself (i.e., increased use of pornography to cope with fears about the virus).

Of the many explanations for the trends described above, a particularly obvious explanation is that use of pornography trended downward because people were, in general, less likely to have time alone to view pornography. Although some people do report using pornography with their partners, pornography use is most often a solitary activity (Kraus & Rosenberg, 2014) and quite often hidden from partners (Willoughby & Leonhardt, 2020). Additionally, among individuals who live with others (e.g., family, roommates), some level of privacy is typically required for one to use pornography. That is, the majority of people are unlikely to regularly view pornography in the company others, particularly when those others are not prospective sexual partners. Given that social distancing measures and travel restrictions led to people spending more time at home with others, it is quite possible that such measures also led to general downward trends in pornography use, though our data do not allow us to directly test this hypothesis.

Finally, we note that pornography use decreased from baseline measures in August 2019 to February 2020 (before the spread of SARS-CoV-2 in the U.S.), suggesting that downward trends in use may have happened without the pandemic. In general, it may be that people use less pornography over time. Although we examined pornography viewing over five time points, we did not measure individuals’ motives for viewing pornography (e.g., enhancement of dyadic sexual activity, assistance in solitary masturbation, alleviation of boredom or stress); it is possible that individuals’ motives for viewing pornography may have changed or shifted throughout the pandemic, particularly as people have found themselves under growing stressors due to recent economic, employment, health, and caregiving challenges attributed to the ongoing COVID-19 pandemic and associated restrictions on activity.

Limitations

Although results in the current study are novel and shed light on unanswered questions around the possible effects of COVID-19 on pornography viewing behaviors among U.S. adults, they are not without limitations. First, we used a short measure, the Cyber Pornography Use Inventory-4 (CPUI-4; Grubbs & Gola, 2019), to assess for PPU in the current study. The use of a brief PPU measure for a longitudinal study is advantageous (i.e., reduces burden and time for participants), but it also lacks the diagnostic accuracy of a clinical interview or clinically validated measure. Further work using a validated clinical measure of PPU, such as the Problematic Pornography Consumption Scale (Bőthe et al., 2018), would likely provide a better diagnostic picture of PPU. Second, although it is beyond the scope of this paper, further work is also needed to identify factors (e.g., demographic, clinical, personality) that can predict the development of PPU or changes in PPU status over time, particularly during periods of significant stress or unrest due to the COVID-19 pandemic. Third, we did not examine the possible effects of moral incongruence on self-reported PPU as noted in prior works (e.g., Grubbs, Lee, Hoagland, Kraus, & Perry, 2020), which suggests that religiousness can moderate the relationships between pornography and self-reported PPU. Fourth, we did not examine the potential effects of pornographic content consumed or whether or not individuals felt as if their preferences in pornographic content shifted or became problematic over the course of the pandemic. We also note that our measure of symptoms of depression and anxiety, the PHQ-4, although widely used as a general screening measure of such distress, is not a diagnostically precise instrument and only briefly captures symptoms of depression and anxiety. Symptoms of loneliness, feelings of boredom, COVID-19 specific anxiety, and general stress levels associated with pandemic-related lifestyle changes were not assessed and may have demonstrated different trends than what we observed in PHQ-4 scores. More simply, general depression and anxiety may not have been the best measure of pandemic-related distress.

Behavioral Ecology of the Family: Harnessing Theory to Better Understand Variation in Human Families

Behavioral Ecology of the Family: Harnessing Theory to Better Understand Variation in Human Families. Paula Sheppard, Kristin Snopkowski. Soc. Sci. 2021, 10(7), 275; Jul 19 2021. https://doi.org/10.3390/socsci10070275

Abstract: Researchers across the social sciences have long been interested in families. How people make decisions such as who to marry, when to have a baby, how big or small a family to have, or whether to stay with a partner or stray are questions that continue to interest economists, sociologists, demographers, and anthropologists. Human families vary across the globe; different cultures have different marriage practices, different ideas about who raises children, and even different notions of what a family is. Human behavioral ecology is a branch of anthropology that is particularly interested in cultural variation of family systems and how these differences impact upon the people that inhabit them; the children, parents, grandparents. It draws on evolutionary theory to direct research and generate testable hypotheses to uncover how different ecologies, including social contexts, can explain diversity in families. In this Special Issue on the behavioral ecology of the family, we have collated a selection of papers that showcase just how useful this framework is for understanding cultural variation in families, which we hope will convince other social scientists interested in family research to draw upon evolutionary and ecological insight in their own work.

Keywords: human behavioral ecology; kinship; marriage systems; cross-cultural variation; family formation; cooperation and conflict; cooperative breeding; kin networks

3. Conclusions

In this Special Issue, we illustrate the benefits of applying a theoretical framework to create directed research that can complement data-driven methods so commonly used in other social sciences such as demography and quantitative sociology. Human Behavioral Ecology recognizes that the currency that people are trying to maximize is fitness5, not wealth or status, or even health, even though those things are often quite strongly associated with fitness. This insight is the grounding of all HBE hypothesis-testing and can be harnessed to explain the immense variation in human social behavior. It can also explain how apparently illogical behavior, such as life-threatening risk-taking, or not pursuing a high-education pathway, may be a logical choice for some people given their current circumstances.
Human behavioral ecology is not only useful for understanding why people do the things they do but it has policy-relevant applications too. For instance, if we recognize that teenage pregnancy is often the product of limited choices and an unknown future that young women have in high-mortality neighborhoods (Geronimus et al. 1999) policymakers can focus attention on providing ways to improve young women’s health. Similarly, policy focused on reducing poverty, such as Universal Basic Income (Nettle 2018) can remove the insecurity of the future enabling people to prioritize long-term goals over short-term risks.
Here we have gathered an array of articles that demonstrate how the rich ecologies we inhabit as a diverse species can explain the myriad different family structures, reproductive outcomes, and social networks that we see across the world. We have also demonstrated the value of conducting cross-cultural research, not only because those cultures are intrinsically interesting but also because a global perspective can provide insights about societies and behavior in the global North.

Determinants of the Arab Spring Protests in Tunisia, Egypt, and Libya: The role of economic factors was inconsistent, whereas political grievances were more clearly related to the motive to participate in the uprisings

Determinants of the Arab Spring Protests in Tunisia, Egypt, and Libya: What Have We Learned? Zahraa Barakat, Ali Fakih. Soc. Sci. 2021, 10(8), 282; July 23 2021. https://doi.org/10.3390/socsci10080282

Abstract: This paper provides empirical evidence on the determinants of protest participation in Arab Spring countries that witnessed major uprisings and in which social unrest was most pronounced. Namely, this paper investigates the latter in Tunisia, Egypt, and Libya using a micro-level data survey, the Arab Transformation Survey (2015). The findings of our probit regression analysis reveal that gender, trust in government, corruption concern, and social media usage have influenced the individual’s perception of protest activism. We find evidence that the role of economic factors was inconsistent, whereas political grievances were more clearly related to the motive to participate in the uprisings. We then control for country-specific effects whereby results show that citizens in each country showed different characteristics of participation. The findings of this research would set the ground for governments to better assess the health of their societies and be a model of governance in the Middle East.

Keywords: Arab Spring; participation; protesting; probit model

6. Conclusions

This paper examines the factors behind participation in the Arab Spring demonstrations in Tunisia, Egypt, and Libya. Findings for all three countries reveal that set of socioeconomic and sociopolitical factors have established a motivation behind an individual’s decision to protest. The willingness to participate in uprisings was shown to be driven by political grievances rather than economic factors. The intention of such a result may reinforce the main determinant for conflict in weak MENA communities, suggesting that aspects of state fragility in MENA seem to be different than other societies in the world (Kivimäki 2021).
We find that the gender gap is significant in the examined sample, lack of trust in government showed to be a significant trigger towards protesting, social media played an essential role in influencing people to take part in protests, and governments’ attempts to combat corruption tend to decrease the probability of bringing people into streets. Indeed, each country had its roots for the uprisings; hence, our results show a substantial difference among the studied countries in citizens’ pattern toward rebellion. For instance, corruption and inequality seemed to increase the likelihood of protest participation in Egypt. We also find evidence that Egyptians with good health and who are satisfied with the economic development in their countries were engaged in political activism more often than those who are dissatisfied. As for Libyan citizens, males were more probable to join revolts. It was found that corruption, political freedom, lack of trust in government, and social media usage are the main drivers to prompt the protesting mechanism in Libya; however, satisfaction with the social security played a positive role in influencing people to join revolts. Lastly, Tunisia showed a gender gap difference in protest involvement. Regardless of the low magnitude, youth engagements tend to be significant, and usage of social media was correlated with a higher likelihood for political participation.
To further validate our findings, we can include other countries, increasing our sample size to helps us draw more accurate generalizations. Adding more economic indicators that were unfeasible to us and essential in having a better understanding whether participants were motivated by political change or economic grievances.
To reach a more diversified understanding of the “Arab Spring” and its broader implications requires looking at their margins; hence, the narration of the “Arab Spring” employing a more in-depth approach. Although revolts used the same slogans calling for freedom and the fall of the “regime”, considering them as a single revolution indicates a misguided viewpoint given the differences between distinct Arab countries (Ventura 2016, p. 285). Many groups anticipated their movements such as the “Arab Spring” for recognition purposes. On the other hand, terms such as Arab awakening is linked to a “Neo-Orientalist” world-view calling for people’s awareness in the Arab world about the West’s approach to portraying them as oppressed, under-civilized, and lacking agency, to the idea of “Arab despotism” and the belief that Western philosophical theology is the only path towards modernity, or the “Islamist Winter”, which was employed to swing the focus of the social movement to political and security threats (Huber and Kamel 2015, p. 129Al-Kassimi 2021). In this context, the representation of the events taking place in MENA seems to be generalized and associated with the myth of “Oriental despotism” (Ventura 2016, p. 286). The neo-orientalist approach can be recognized based on how rebellions were gendered by considering how Arab women were seen as victims of oppression and required saving (Al-Kassimi 2021). For instance, Western media deployed a gendered issue out of the uprisings and the continuous calls for women’s rights confirm their “Orientalism” (Mahmood 2006Abu-Lughod 2013Abbas 2014Ventura 2016, p. 291). Moreover, to state that all Arab are Muslims represents a neo-Orientalist myth (Mahmood 2006Abu-Lughod 2013Abbas 2014). The participation of women in the protest challenges the neo-orientalist approach whereby a broad range of females were involved in the protests. Whether on the ground or their heavily online presence on social media platforms, such as Leila-Zahra, Esraa Abdel-Fattah, and Lina Ben Mhenne, they played a major role as activists in women empowerment agenda. Such a deterministic frame necessitates a deeper recognition and deconstruction (Khalid 2015, p. 163). Of note, Western modernity has refuted the ideology of Arab women as being rational and competent authors of their political lives by limiting the intricacy of Arab cultural heterogeneity across the Mashreq and Maghreb (Al-Kassimi 2021, p. 26).

7. Policy Implications

Understanding the factors that gave rise to the uprising helps to better assess the health of our society and to provide guidance for strategies ensuring political stability. Governments shall rely on two main pillars to build citizenship and minimize the risk of political instability. The first pillar is forming an anticorruption ecosystem by taking solid and firm actions to fight the existing corruption. Some measures include restructuring the judicial system to avoid bribes and irregular payments, investigating and penalizing those involved in corrupt acts within the public administration, and seizing assets where wealth cannot be explained, subject to judicial oversight (Morgan 1998). The second pillar is building transparency and trust between citizens and the government. Though efforts to earn public trust are limited, transparency is assumed to be crucial (Kettl 2017). A vital prerequisite for that is creating portals where government spending is published regularly allowing citizens to track all the ongoing projects and initiatives. It is worth noting that governments can adopt social media to provide complementary information broadcasting, communication, and participation channels whereby citizens can access government services and also government officials be able to make more informed decisions. Countries can also put citizens at the heart of policy making by offering them the opportunity to shape legislation in areas that they care most about by voting on policy proposals. Transparent, unbiased, and inclusive policy making helps in improving democratic performance (Shah 2007).

Lethal coalitionary attacks of chimpanzees on gorillas in the wild

Lethal coalitionary attacks of chimpanzees (Pan troglodytes troglodytes) on gorillas (Gorilla gorilla gorilla) in the wild. Lara M. Southern, Tobias Deschner & Simone Pika. Scientific Reports, July 19 2021. DOI: 10.1038/s41598-021-93829-x

[Popular version: https://www.mpg.de/17223684/0719-evan-lethal-attacks-by-chimpanzees-on-gorillas-observed-150495-x. Here, climate change shows up three times (also appears there as a keyword), while in the paper there is no occurence of climat*, warm*, or temperat*. Also, in the paper's 90+ references, the titles do not make mention of those three word stems.]

Abstract: Intraspecies violence, including lethal interactions, is a relatively common phenomenon in mammals. Contrarily, interspecies violence has mainly been investigated in the context of predation and received most research attention in carnivores. Here, we provide the first information of two lethal coalitionary attacks of chimpanzees (Pan troglodytes troglodytes) on another hominid species, western lowland gorillas (Gorilla gorilla gorilla), that occur sympatrically in the Loango National Park in Gabon. In both events, the chimpanzees significantly outnumbered the gorillas and victims were infant gorillas. We discuss these observations in light of the two most widely accepted theoretical explanations for interspecific lethal violence, predation and competition, and combinations of the two-intraguild predation and interspecific killing. Given these events meet conditions proposed to trigger coalitional killing of neighbours in chimpanzees, we also discuss them in light of chimpanzees’ intraspecific interactions and territorial nature. Our findings may spur further research into the complexity of interspecies interactions. In addition, they may aid in combining field data from extant models with the Pliocene hominid fossil record to better understand behavioural adaptations and interspecific killing in the hominin lineage.

Discussion

Here, we report the first observations of two lethal coalitionary attacks of chimpanzees on another hominid species, gorillas. In both events, the chimpanzees considerably outnumbered the gorillas, however in the second event, the lethal attack started when the silverback had abandoned his group. In both events, the victims were gorilla infants, but the consumption of the victim was observed in one event only.

Recent studies59 were able to distinguish genetically distinct gorilla groups within the study area; when overlaid against the Rekambo chimpanzee community home range there was clear overlap with seven distinct gorilla groups (see Supplementary Fig. S1 in the Supplementary information). However, further data are needed to clarify whether our rare observations are due to lack of data or indeed mirror true frequencies of interspecies interactions in the study area.

In the following paragraphs, we will present and discuss several possible explanations that may account for the two lethal coalitionary encounters observed.

One explanation may be that the observed events represent cases of predation with the chimpanzees hunting and opportunistically targeting the smaller-bodied gorilla infants as prey. Although differences in behaviours accompanying hunting and hunting patrol patterns have been observed across sites, the behaviors observed at Loango were similar to the patterns reported for Taï41,60 and Ngogo38. For instance, the chimpanzees showed conspicuous behaviours prior to hunting such as being extremely attentive to any arboreal movements, scanning, changing directions several times without vocalizing, and performing specific call types—hunting calls38,45. Post-hunting behaviour is characterized by the prevalence of high-ranking males as the primary prey possessors and consumers, high levels of attention, arousal and excitement of party members, as well as begging and food sharing13,40,41,41,61. However, the behaviours observed during the two events were very different to those reported during hunting: The chimpanzees were noisy, emitted alarm barks and screams and performed displays long before the infants were killed. The excitement levels dropped immediately following the death of the infant gorillas. In addition, the observed feeding behaviours during the two events also differed from patterns expected during conventional hunting for the purpose of gaining nutritional benefits through the consumption of prey27. In the first encounter no feeding behaviour was observed, and in the second event the gorilla infant was almost entirely consumed by a single adult female. In contrast to species-typical hunts, in the second event the majority of individuals present, including adult males, showed almost no interest in the carcass, and only small amounts of meat were exchanged between low ranking individuals.

Another explanation may be that the two cases are the product of interspecific competition such as IGP and IK. So far, studies investigating interspecific competition in gorillas and chimpanzees have provided evidence for dietary niche differentiation and mutual avoidance to limit competition e.g.,62,63,64,65,66,67. All previous accounts of interspecies interactions as well as co-feeding events have been reported as peaceful despite a relatively high potential for feeding competition concerning key resources or during certain periods e.g.,68,69,70. Thus far, aggressive interference competition, including infanticide, has been observed between monkey species (e.g., Cercopithecus nicitans stampflii, Cercopithecus diana diana71; Ateles hybridus, Alouatta seniculus72) but not between chimpanzees and gorillas. Such interactions are however frequent in carnivore species and have been suggested as key determinants of their abundance and distribution33,73 (but see for an overview of other taxa31). As in the lethal interactions discussed here, carnivores tend to attack their closest dietary competitors31, most agonistic encounters occur in seasonal environments when food is scarce27, and killings decrease abruptly when dietary overlap is reduced73. Gorillas and chimpanzees show considerable dietary overlap and have a relatively high potential for dietary competition45,74. Across study communities, the degree of dietary overlap ranges between: 50% Kahuzi-Biega; Gorilla beringei graueri, Pan troglodytes schweinfurthii75 and 60–80% Loango, Lopé, and Ndoki; Gorilla g. gorilla, Pan t. troglodytes66,74,76. The two lethal encounters we observed occurred at times characterized by food scarcity and a period of high dietary overlap (for fruit resources)45,74—February and December 2019. In contrast, the two previously observed peaceful co-feeding events took place in April, a month characterized by relatively low dietary overlap between the two species45,74.

Furthermore, age, size and patterns of grouping seem to play a significant role in the outcome of IGP’s and IK’s (see e.g.,27). While relative body size of the opponents is the primary determinant of lethal interactions and results in favour of the larger species, in interactions involving adults, smaller species frequently kill the young of larger species27,73. There are cases where smaller species were able to kill or deter larger species such as wolves (Canis lupus) killing adult black bears (Ursus americanus)77 and hyenas (Crocuta Crocuta) killing lions (Panthera leo)27, however, these outcomes were only possible when individuals of the smaller species formed coalitions27,77. The grouping style of a species was found to strongly influence the outcome of IGP’s resulting largely in favour of species that form groups78. This is in line with our current observations, where the chimpanzees were at an advantage even against the larger gorilla species, given their ability to cooperate. Additionally, specific adaptations to prey-capture also influence the outcome of IGP’s, resulting in favour of species more adapted for vertebrate predation73 where the successful species, here, the chimpanzee, has adaptations to vertebrate predation13,39,41. Hence, as in IGP food webs (with specific emphasis of species classification) portrayed by Arim and Marquet79, the two reported killings may represent cases of IGP and IK between an intermediate omnivorous species (i.e. broad diets comprising both animal and plant foods80), the chimpanzee, and a herbivorous species (feeding mainly on plant foods81), the gorilla.

Lastly, both of the lethal encounters reported here also showed similarities to behaviours observed during chimpanzee intercommunity encounters. For instance, similar to territorial patrols, where chimpanzees move to the periphery and beyond their territorial boundaries to search for neighbours e.g.,11,13,82,83, the observed events took place in the peripheries of the territory before and during territorial patrols. In both events, infants were targeted and adult males were the main attackers and played the most active roles. Similarly, in lethal chimpanzee intercommunity encounters, infanticide is common and adult males are the main participants11,83,84,,83,84 (but see for female roles51). It has been proposed that in chimpanzees, adult males may kill infants of other communities to reduce competition for food by inducing foreign females to avoid contested regions84. The observed interspecies killings of gorilla infants by chimpanzees could have similar motivations85. We also observed behaviours before and during the encounters characteristic to coalitionary intercommunity encounters such as aggression (e.g., charges, chases, threatening displays, contact aggression), high levels of arousal and the use of loud vocalizations13,14,15,51. The imbalance-of-power hypothesis postulates that the function of unprovoked intercommunity aggression (such as deep incursions into other chimpanzee communities’ territory and coalitionary attacks) is a drive for dominance over neighbours resulting in fitness benefits for the attackers through improved access to resources such as food, females, or safety6,13. Two conditions are proposed to be required to trigger coalitional killing of neighbours: (i) a state of intergroup hostility, and (ii) sufficient imbalances of power between interacting parties resulting in impunity from aggressors. Thus, it may be possible that at Loango, which is characterized by relatively high dietary food overlap in specific months45,74, gorillas are perceived as competitors, for both space and resource use, similar to members of other chimpanzee communities. Lastly, we cannot rule out that the presence of human observers, in both events, may have had an effect on the unhabituated silverback’s departure and may have tilted the imbalance of power in favour of the habituated chimpanzees.

In sum, the observed events show similarities to patterns reported in IGP’s, IK’s and intraspecies agonistic encounters. Ultimately, additional observations in combination with isochronous assessments of fruit availability and dietary overlap are needed to differentiate whether coalitionary attacks are indeed the output of interspecific predation spurred by opportunistic hunting, interspecies competition for food resources or whether these interactions are merely a non-adaptive by-product of the “xenophobic nature” of chimpanzees. Finally, analyses of long-term phenological data could aid in investigating if potential high levels of feeding competition may be a more recent phenomenon caused by a collapse in fruit availability as observed in other tropical forests in Gabon86.