Monday, August 31, 2020

Positive relationship between intolerance & perceived homosexuality; The more a given gender-role violation is thought to implicate homosexuality, the more negatively/less positively people tend to react to the violation

Differential Reactions to Male and Female Gender-Role Violations: Testing the Sexual Orientation Hypothesis. Ursula A. Sanborn-Overby & Kimberly K. Powlishta. Archives of Sexual Behavior (2020). Aug 31 2020.

Abstract: Previous research has found that gender-atypical males are evaluated more negatively than gender-atypical females. According to the sexual orientation hypothesis, this asymmetry in evaluations occurs because the feminine characteristics taken on by males when they violate gender roles are more closely tied to perceived sexual orientation than are the masculine characteristics of gender-atypical females. The current series of studies were designed to confirm the existence and generality of the asymmetry phenomenon (Study 1), the preconditions for testing the sexual orientation hypothesis (Study 2), and then to test the hypothesis itself (Study 3). Study 1 found that, as predicted, adults (N = 195, females = 97) displayed more intolerance of males than of females committing gender-role violations across a wide variety of characteristics within multiple domains, although the existence of asymmetry varied somewhat depending on the domain. Study 2 revealed that, as predicted, adults (N = 196, females = 117) believed that gender-role violations indicate homosexuality more so for males than for females overall and across all four domains studied (occupation, activity, trait, and appearance). Study 3 directly tested the sexual orientation hypotheses by examining the relationship between intolerance of specific gender-role violations (scores from Study 1) and the perceived homosexuality associated with those violations (scores from Study 2). Overall, there was a positive relationship between intolerance and perceived homosexuality, indicating that the more a given gender-role violation is thought to implicate homosexuality, the more negatively/less positively people tend to react to the violation, consistent with the sexual orientation hypothesis.

We find a ‘good-looking giver’ effect–that more physically attractive people are more likely to engage in giving behaviors, and vice versa

The Good-looking Giver Effect: The Relationship Between Doing Good and Looking Good. Sara Konrath, Femida Handy. Nonprofit and Voluntary Sector Quarterly, August 28, 2020.

Abstract: Evidence exists that beautiful is seen as good: the halo effect wherein more physically attractive people are perceived to be good, and the reverse halo that good is seen as beautiful. Yet research has rarely examined the evidence linking the beautiful with the good, or the reverse, without the halo effect. We examine the relationship between physical attractiveness (beauty) and giving behaviors (good), where ratings of attractiveness are independent of giving behaviors. We use three U.S. datasets: (a) a nationally representative sample of older adults (NSHAP), (b) a nationally representative longitudinal study of adolescents (ADD Health), and (c) the 54-year Wisconsin Longitudinal Study (WLS), to present evidence that these two characteristics (attractiveness and giving) are indeed correlated without the halo effect. We find a ‘good-looking giver’ effect–that more physically attractive people are more likely to engage in giving behaviors, and vice versa. Thus, in ecologically valid real-world samples, people who do good are also likely to look good.

Keywords: physical attractiveness, halo effect, beauty, prosocial behavior, giving behaviors

Expressions of Sexual Deviance in Black Serial Killers: The number of Black serial killers has increased, but empirical studies have not focused on this unique population

Expressions of Sexual Deviance in Black Serial Killers. Lucia J. Weatherall. PhD Thesis, Walden Univ, 2020.

Abstract: The number of Black serial killers (BSKs) has increased, but empirical studies have not focused on this unique population, including their expressions of sexual deviance. The purpose of this case study was to understand the common socialization experiences and the expressions of sexual deviance in BSKs. Two conceptual frameworks were used to identify the concepts to explore: Bandura’s social learning theory of aggression and Agnew’s general strain theory. Data collected came from archival court and police records in Texas. A content-analysis approach was used to analyze the archival data, organized by criminal background, sexual deviance, familial data, and social development. The results identified rape and sadism as the primary expressions of sexual deviance in BSKs. The level of aggression and trauma experienced during childhood was consistent across all cases. The results, while limited by the lack of interviews with family and law enforcement, indicated that BSKs present a social problem and have an adaptive skill not hindered by mental impairments or limited education. The results suggested empirical research needs to explore aggression and strain on African American children, the possible connection to the lack of paternal involvement, and expressions of sexual deviance in BSKs. Future research on BSKs can help create an accurate profile to assist law enforcement agencies identify predators.


The unique and consistent findings offer a meaningful contribution to the forensic
psychology community and adding to the literature on BSKs. The common theme of
negative parental support (and associated strain) with childhood trauma indicates a
potential connection to aggression, sexual deviance, and serial murder as an adult. The
data confirmed the presence of aggression during social development of the 14 BSKs
either during childhood or expressed at an adult. I plan to use the result for presentations
to law enforcement agencies at the local, state, and federal level. Providing law
enforcement with additional data could assist with the pursuit and capture of this
population. I plan to give presentations, discussing the negative familial exposure and
strain during childhood, focused at the juvenile justice system.
Furthermore, the implications of this study can assist various law enforcement
agencies. Presentations can assist agencies with investigation practices and techniques to
help identify victims of BSKs, who would otherwise go unnoticed or unidentified as
victims of a serial killer. For example, law enforcement agencies should review the
procedures in place when responding to missing persons reports or deaths of the missingmissing
population. Far too often, agencies dismiss the reports as a voluntary choice
when the individual lives a transient lifestyle, allowing BSKs longer crime sprees. The
lack of a comprehensive investigations into the cause of deaths for the missing-missing,
as in Case #14, suggested a dismissive approach in providing closure for the victims and
their families. Law enforcement agencies, using systems to capture forensic evidence and
search DNA profiles compared to cold cases, increased the number of BSKs identified.
The lack of communication between law enforcement agencies in sexual assaults,
missing persons, and murders allowed BSKs to prey upon women, elderly, and the
missing-missing. Additional implication included increased communications between
jurisdictions, and sharing of information on criminal activities, to identify patterns more


In summary, the purpose of the study described the expressions of sexual
deviance in BSKs. The study determined BSKs rape their victims as the most common
expression in sexual deviance. The study also suggested BSKs do not always murder the
victims they rape, and instead express sexual deviance through sadistic acts. The results
of the study determined BSKs remain out of the social spotlights and off the radar of law
enforcement agencies. The study suggested that BSKs prey upon all levels of society, and
across racial demographics. Although the missing-missing remain a vulnerable and easily
forgotten victims, BSKs kills women, children, and men. BSKs who committed murders
over extended time used various methods to kill their victims as an adaptive method to
avoid detection.
The results of the study suggested BSKs have a common pattern during
childhood. BSKs exposed to abuses, aggression, and violence within their families and
social development did not receive attention or a proper outlet. The underreporting of
psychological interventions of African American boys could result from the belief
systems that do not encourage weakness (Lester & White, 2014; Voison et al., 2013).
BSKs with a limited education or intellect demonstrated an adaptability to aid with their
criminal activities. The socially adaptive behaviors and criminally adaptive skills
demonstrated by BSKs with lower IQ suggested a level of planning, premeditation, and
deception. The finding conflicted with profiles on serial killers. This misconception
benefited the BSKs population as they continued to navigate below the radar; until DNA
matches (found by computers) caught up to them. The potential for a connection in
expressions of sexual deviance and a lack of paternal figures during childhood requires
the consideration of future studies.
The research on WSKs provided law enforcement agencies and researchers with a
vast pool of data to profile perpetrators and reduce the number of their victims.
Documentaries on WSKs (i.e. Ted Bundy, Jeffery Dahlmer, and Todd Kohlhepp)
provided intrigued audiences hours of information into their lives, motives, and victims.
Meanwhile, BSKs (like their White counterparts) also have the appearance of normalcy
(Arndt et al., 2004; Beasley, 2004; Hickey, 2015; Kraemer et al., 2004) and continued to
thrive undetected by law enforcement, family, friends, and co-workers. Case #11 lived a
normal life, working as a waiter and taking care of his family. His common-law wife
found it hard to believe she lived with a serial murderer; until DNA evidence linked him
to a series of rapes and murders near their home. Case #14 methodically and with malice
murdered almost 100 women, for almost four decades, across the United States.
Black men commit serial murder. BSKs present a social problem that requires
more research and law enforcement consideration. Empirical research needs to explore
the effects of exposure to aggression, violence, and strain during childhood on African
American. Additionally, studies on the expressions of sexual deviance in BSKs, and the
possible connection to paternal involvement. The results of the case study demonstrated
BSKs possess an adaptive skill, a flexibility with victim selection, and variation of
expressions in sexual deviance; not hindered by mental impairments or limited education.
Last, research on BSKs would allow for a more accurate profile to assist law enforcement
agencies. The social aggression and strain experienced during childhood manifest into
actions, including rape and sadistic violence. Additional research on BSKs would provide
beneficial information to develop interventions for at risk youths. Addressing the
aggression and strain experienced during childhood might provide a healthy outlet. Left
unaddressed we have a society at risk of finding a place on the carrousel of victims,
spinning in the mind of a predator.

Imagination, the Brain’s Default Mode Network, and Imaginative Verbal Artifacts

Carroll J. (2020) Imagination, the Brain’s Default Mode Network, and Imaginative Verbal Artifacts. In: Carroll J., Clasen M., Jonsson E. (eds) Evolutionary Perspectives on Imaginative Culture. Springer, August 29 2020.

Abstract: The purpose of this chapter is to explain how imaginative verbal artifacts are produced by the imagination and in turn influence the imagination. Assimilating recent neuroscientific research on the evolution of modern brain shape and on the brain’s default mode network, we can now say with confidence that the imagination is a neurological reality, that it is lodged in specific parts of the brain, that it consists of an identifiable set of components and processes, that these components and processes have adaptive functions, and that in fulfilling its functions imagination has been a major causal factor in making Homo sapiens the dominant species on earth. The first section of the chapter defines the main terms in this argument. The second section describes the evolution of modern brain shape and suggests the role imagination has played in producing the complex of behaviors that characterize neurologically modern Homo sapiens. The third section describes the current neuroscientific understanding of the brain’s default mode network—the neurological locus of imagination. The fourth section describes three core processes of imagination used in constructing imaginative verbal artifacts: simulation, mental time travel, and perspective taking (also known as “Theory of Mind” and “mentalizing”). The three processes are illustrated with reference to a modern American novel, Wallace Stegner’s Angle of Repose. The fifth section describes four specialized forms of imagination that deploy the core processes: dreaming, mind-wandering, autobiographical narratives, and counterfactual thinking. That section explains how these forms are involved in writing or reading literature and identifies a few literary works that illustrate them. The final section sums up the argument for the adaptive functions of literature.

Keywords: Imagination Globular brain Default mode network Literature Simulation Mental time travel Perspective taking Spontaneous thought Literary theory

The Role of Aesthetic Style in Alleviating Anxiety About the Future

Carney J. (2020) The Role of Aesthetic Style in Alleviating Anxiety About the Future. In: Carroll J., Clasen M., Jonsson E. (eds) Evolutionary Perspectives on Imaginative Culture. Springer, August 29 2020.

Abstract: Though few would dispute that aesthetic style is a vehicle for cognitive effects, there is little systematic work that views style from anything other than a historical perspective. This chapter will outline how style, broadly conceived, can be understood as an attempt to avoid anxiety by gaining predictive traction on the future. The central claim will be that style evolved as complexity reduction device, to the extent that it is a predictive scheme that balances explanatory simplicity against model accuracy. I shall show that every given style achieves this by saturating the perceptual environment with evidence for a particular model of the world. This account of style explains several features of its target phenomenon, including its normative character, its polemical nature, and its transitory duration. It also allows for style to be seen as continuous with other complexity reduction strategies on the part of biological agents more generally. The discussion will be supported by a historical appreciation of how style has been theorized in the past, but my overall framework will be provided by information theory.

Keywords: Anxiety Style Prediction Aesthetics Cognition Model building

Women's wellbeing and fertility in rural Tanzania: Overall, women's wellbeing was highest in husband-older marriages, but among women married to older men, spousal age gap was unrelated to wellbeing

Shared interests or sexual conflict? Spousal age gap, women's wellbeing and fertility in rural Tanzania. David W. Lawson et al. Evolution and Human Behavior, August 29 2020.

• We explore whether husband-older spousal age gaps are costly or beneficial to women.
• Women frequently married older men than their stated ideal spousal age gaps.
• Spousal age gap was unrelated to the risk of divorce or to women's fertility.
• Overall, women's wellbeing was highest in husband-older marriages.
• However, among women married to older men, spousal age gap was unrelated to wellbeing.

Abstract: The marriage of older men to younger women is common across cultures. On one hand, husband-older marriage may serve the interests of both sexes, a conclusion broadly consistent with reported gender differences in mate preferences. On the other hand, men alone may benefit from such marriages at a cost to women if seniority enables men to exert dominance in conflicts of interest. Indeed, in public health large spousal age gaps are generally deemed “pathological”, both a cause and consequence of gender inequalities harmful to women. We investigate these alternative models of spousal age gap using data from a cross-sectional survey of women in Mwanza, northwestern Tanzania (n = 993). Consistent with the notion that spousal age gaps are a product of sexual conflict, women typically married with a larger age gap than stated ideals. However, adjusting for potential confounds, spousal age gap was not associated with fertility or the risk of divorce. Furthermore, women's mental health and autonomy in household decision-making was higher in husband-older marriages compared to rare cases of same-age or wife-older marriage. Beyond this comparison, the magnitude of spousal age gaps was unrelated to either measure of women's wellbeing among the overwhelming majority of marriages where the husband was older. Together these findings suggest husband-older marriage does not influence marital stability, relatively large spousal age gaps are neither especially costly nor beneficial to women, and that alternative sociodemographic factors are more important in driving variation in women's wellbeing and reproductive success in this context. Our results support neither a model of mutual benefits, nor a “pathological” conceptualization of spousal age gaps. We conclude by both encouraging evolutionary human scientists to engage more fully with models of sexual conflict in future studies of marriage and mating, and suggesting that public health scholars consider more neutral interpretations of spousal age differences.

Keywords: Spousal age differenceEmpowermentMental healthMarriageTanzaniaSexual conflict

Kin-Avoidance in Cannibalistic Homicide

Kin-Avoidance in Cannibalistic Homicide. Marlies Oostland and Michael Brecht. Front. Psychol., August 31 2020.

Abstract: Cannibalism in the animal kingdom is widespread and well characterized, whereas the occurrence of human cannibalism has been controversial. Evidence points to cannibalism in aboriginal societies, prehistory, and the closely related chimpanzees. We assembled a non-comprehensive list (121 offenders, ~631 victims) of cannibalistic homicides in modern societies (since 1900) through internet-searches, publications, and expert questioning. Cannibalistic homicides were exceedingly rare, and often sex-related. Cannibalistic offenders were mainly men and older than offenders of non-cannibalistic homicides, whereas victims were comparatively young. Cannibalistic offenders typically killed manually (stabbing, strangulating, and beating) rather than using a gun. Furthermore, they killed more strangers and fewer intimates than conventional offenders. Human cannibals, similar to cannibalism in other species, killed and ate conspecifics, occasionally vomited and only rarely (2.5% of victims) ate kin. Interestingly, cannibalistic offenders who killed their blood relatives had more severe mental problems than non-kin-cannibals. We conclude that cannibalistic homicides have a unique pattern of murder methods, offenders, and victims.


Cannibalistic homicides were very rare, often violent, manual and sex-related crimes. Victims were younger and offenders were older than in conventional homicide offenses. Cannibalistic offenders only rarely consumed kin and most who did suffered from serious mental problems.
Our data set consists of 121 offenders with approximately 631 victims. This is a very large number of victims, but note that we are dealing with the entirety of easily accessible cannibalism cases in modern societies since 1900. The case numbers in the US and Germany might be of particular relevance, because, in these two countries, we made a special attempt for a complete coverage of cases. Unsurprisingly, cannibalistic homicide is an exceedingly rare crime, accounting for a minute fraction of homicides. For the US in the period 1960–2018, we estimated the fraction of cannibalistic homicides, being the number of cannibalistic homicides divided by the total homicides [Uniform Crime Reporting (UCR) Program Federal Bureau of Investigation, 2020], to be 0.01%.
The cannibalistic homicides described here had many hundreds of victims but included only one cannibalized neonate. The two other children 2 years or younger killed by cannibalistic offenders were not cannibalized. Since in non-cannibalistic homicides the killing of children 2 years or younger is quite common (accounting for ~2.6% of homicides as reported in FBI data), it appears that this victim population is largely missing in cannibalistic offenses, i.e., we would have expected >15 cases. From a biological perspective, the absence of cannibalistic neonaticide in humans is surprising. Human neonaticide shares many features of cannibalistic neonaticide in rodents and lagomorphs (Sawin et al., 1960DeSantis and Schmaltz, 1984). In humans, neonaticide, as defined by the killing of a neonate on the day of its birth by his/her own mother, incidence varied from 0.07 to 8.5 per 100,000 births (Tanaka et al., 2017). This behavioral pattern is strongly promoted by maternal stress and intrusion by novel partners or detection of predators. Thus, even though neonaticide has been suggested to be a prototypical “biologically” predetermined behavior (Hausfater and Hrdy, 2017), it still shows differences between rodents and humans.
Our data suggest kin-avoidance in cannibalistic homicide. About 97.5% of the victims were non-kin, a statistical difference to occurrence of kin-homicides in conventional homicides (Figure 6). The consanguinity of victim-offender pairs was very low. This conclusion agrees with findings from two other large-scale studies on cannibalistic homicides (Rajs et al., 1998Lester et al., 2015). A diverging result with a large fraction of kin-cannibalism was only observed in one study with only five cases (Raymond et al., 2019). We think these discrepancies reflect different sampling of cases, i.e., while our internet search sampled mostly cases by news coverage, Raymond et al. (2019) focused on psychiatric patients. Indeed, in our sample the cannibalistic offenders with the most obvious mental problems killed more kin (Figure 6D). This reduced kin avoidance in offenders with mental problems might not be limited to cannibalistic homicides. Offenders of conventional homicides in Scotland targeted three times more kin when they had a psychiatric diagnosis at the time of trial. The fraction of kin victims for offenders with a psychiatric diagnosis at the time of trial was 30.9%, compared to a kin victim rate of 11.3% for mentally healthy offenders (Gillies, 1976).
The fact that mental problems can reduce kin-selectivity in cannibalistic homicides does not argue against the existence of strong anti-kin-ingestion mechanisms, whether such mechanisms are a result of nature, nurture, or a combination of both. In rats, there are kin-responsive neurons in the lateral septum (Clemens et al., 2020), which might point to a possible biological basis of kin recognition at least in rodents. Humans use stable psychosocial cues to distinguish different types of kin from non-kin, and the cues used for kin detection depends on the specific dyad (Lieberman et al., 2007Tal and Lieberman, 2008Antfolk et al., 2018Billingsley et al., 2018). One such cue is early co-residence between purported siblings as suggested by Westermarck (i.e., the hypothesis of Westermarck, 1922). It might be that this system of kin detection is affected in offenders with a psychiatric diagnosis and thereby prevents the offenders from recognizing and avoiding kin.
Spitting out conspecifics or parts of them is a characteristic behavior of cannibalistic animals and humans. We found five such throwing up /spitting out events, which may not sound like a lot in 631 victim cases, but our documentation is not comprehensive and it is important to keep in mind that many humans may eat a thousand meals a year without any one such throw up event. In sticklebacks, a strongly cannibalistic fish species, spitting out of newly hatched fish has been carefully documented and referred to as “testing” (Bruijn and Sevenster, 1982). Similarly, the cannibalistic spadefoot tadpoles have been seen to nip at and spit out conspecifics (Pfennig et al., 1993), a behavior referred to as “tasting”. Our observations on humans and a review of the animal literature suggest, however, that it is very unlikely that spitting out meat from cannibalistic events indeed reflects a sensory discriminatory behavior or gustatory “tasting”. The reasons, why we reject the tasting/testing hypothesis are the following: (i) Stickleback, spadefoot tadpoles, and humans have potent non-gustatory kin-discrimination mechanisms. In stickleback (Mehlis et al., 2008) and in salamander tadpoles (Pfennig et al., 1994), such mechanisms are olfactory in nature and in humans and apes (Parr and de Waal, 1999) such mechanisms are presumably visual; (ii) when tested intadpoles by nare occlusion, olfactory mechanisms were necessary for kin discrimination, whereas the remaining gustatory mechanism (after nare occlusion) were insufficient for kin-discrimination (Pfennig et al., 1994); (iii) human gustatory kin-discrimination appears highly implausible from our screening of cannibalism reports. On numerous occasions, human meat was sold (and probably eaten) by cannibals as ostrich, pork, horse, or tenderloin, mostly without any customer complaints reported. For instance, J.R.M. sold meat of his victims as special barbecue meat in a stand next to his trailer. He mixed the meat together with pork, which he claims tastes very similar to human meat, so that nobody could tell the difference (Serial killer who “cut up victims and sold them as BBQ” dies, 2017). If humans cannot discriminate human meat from beef, how could humans or animals taste kin? (iv) “Testing” behavior in stickleback is strongly dependent on the state of satiation (Bruijn and Sevenster, 1982); it is not obvious why a sensory discriminatory behavior should strongly depend on the state of satiation; and (v) in interviews with human cannibalistic offenders, they do not report that kin had a bad taste. We propose an alternative explanation for cannibalistic spitting-out: We suggest that this behavior is driven by internally generated repulsion and reflects a conflict between kin-protective, anti-cannibalistic drives, and predatory/consumptive systems. This explanation makes sense, because (i) we do not assume gustatory kin-discrimination, (ii) it is consistent with strong dependence on internal variables like hunger, and (iii) it fits with reports from cannibalistic offenders. In our explanation we explain a contradictory behavior (spitting out, a reversion of the decision to ingest), by an internal contradiction (preying vs. protection of potential kin).
Forensic awareness could be another explanation for the kin-avoidance observed in our study. Accordingly, cannibalistic offenders would avoid eating kin in order to escape prosecution, which is conceivably more likely for kin offenses. While we think forensic awareness is an important consideration, we do not think this hypothesis can fully explain our data. In particular, we do not see any evidence for a differential “forensic awareness” of cannibalistic and conventional offenders. Instead, many cannibalistic offenders enjoyed the celebrity emanating from their deeds; indeed, cannibal P.K. sends a letter to the press detailing the whereabouts of the grave of one of his victims, an action not speaking to forensic awareness. Also, other considerations do not align with the forensic awareness hypothesis. Offenders of cannibalistic crimes who showed forensic awareness were excluded from this study. For example, it is thought that the “confession” of cannibalism by E.K. is the result of forensic awareness, and he is, therefore, excluded from this study on the grounds of not enough evidence for cannibalism (Supplementary Data Sheet 3). However, we cannot exclude that other offenders still included in our study had a similar tactic unknown to us. It could be that offenders with forensic awareness will target strangers more often than family to dismiss any suspicions which might fall on them. In that case, one might argue that a reduced mental health also likely reduces the forensic awareness and that that could explain our finding that offenders with reduced mental health targeted kin more often. While we can not exclude this theory, we deem it unlikely because (i) this would then also be true for non-kin relatives such as intimate partners, and this is not the case (Figure 6E), and (ii) we excluded cases with suspicions of forensic awareness, and in first-hand reports by cannibals included in this study, they claim to really kill and eat for the purpose of pleasure, and (iii) cannibalistic offenders, who had enough forensic awareness to never be detected, are also not included in this study for the obvious reason that they are unknown. According to the theory above, uncaught cannibalistic offenders would target strangers more often than family, and those cannibals are missing from our study. Thus, if this is true, we are missing more strangers victims but we are not missing as many kin victims, in which case the actual effect size would be even larger than reported here.
War and hunger related cases of cannibalism appear to share features of cannibalistic homicide identified here. In war crimes, it is often the enemy which is cannibalized (Tanaka, 2018). In hunger-related cannibalism there are also indications of kin-avoidance. In the famous Uruguayan Air Force flight 571 incident, where starving victims of the plane crash fed on meat from deceased co-passengers to survive, it is said that at least some survivors made efforts to avoid eating kin (Arijón, 2008). Specifically, when one of them could only eat his kin for survival, he decided to cross the Andes to search for help instead (Parrado and Rause, 2013), which is the journey which eventually led to their rescue. Internally generated disgust is evident in such cases, i.e., the plane crash victims were appalled by eating human meat.
To achieve a correct interpretation of the results reported here, it is necessary to consider the limitations of our data set. Cannibalistic homicide is a secretive crime and our study is based on second hand and potentially distorted information. Thus, despite the best of our efforts, some errors are inevitable and we expect that our data set may contain mistakes about homicides, offenders, victims, and victim-offender relationships. The case of cannibalistic offender J.K. provides a warning. No less than five putatively innocent people were arrested for his crimes (three of whom committed suicide and a fourth was wrongly convicted of murder). Furthermore, some homicide offenders may give a calculated “confession” of cannibalism in order to use an insanity plea, as is suspected to be the case with E.K. (who for this reason has been excluded from this study, see Supplementary Data Sheet 3). In anthropology, the mere existence of human cannibalism in, for example, aboriginal cultures has been questioned on grounds of sensationalistic reporting in travelogs (Arens, 2004). Does this mean that one can dismiss our evidence about cannibalistic homicides, because these crimes seldom have eyewitnesses or video evidence and, without exception, incidents have been hyped by the press? We think the answer is a resounding no. The hundreds of cases documented in our report leave no room for doubt. We acknowledge, however, that our worldwide collection of cases is subject to a variety of sampling biases.

Limitations of Our Approach

The value of the data provided in our study might be limited by the following weaknesses:
1. The secretive nature of cannibalistic homicide. Cannibalistic homicide is nothing that can be openly performed in modern societies. The vast majority of cannibalistic homicides described here have been performed secretively and often there have been considerable efforts by offenders to destroy evidence. Hence, this paper largely describes deeds that nobody witnessed and cannibalism – the defining characteristic of what is talked about here – has rarely been directly established.
2. The need for estimates. Given the secretive nature of cannibalistic homicide, many details of the offenses described here can only be estimated. Many of these estimates are based on excellent evidence such as confessions, post-mortem examinations, or strongly suggestive circumstance (a child’s hand cooking in salted water on the stove), but nevertheless the evidence remains inferential.
3. Sampling biases. Perhaps the biggest problem of the data presented here is that our “news-based” search for cannibalistic incidents is subject to sampling biases. In particular, the data presented here will be biased towards particularly newsworthy cases with high victim numbers or gruesome case details.
4. Outright distortions. Sensationalism in the press might also lead to inflated presentation of evidence and distortion of the facts.
5. Reliance on second hand information. Our data set relies largely on web and newspaper reports and less so on official documents (original verdicts, interviews, letters and notes from the cannibal offender, autobiographies by offenders, and the like). Hence, verification of incident details is largely indirect.
6. Unintentional mistakes. Our data set is very large and unquestionably contains mistakes. Such mistakes would happen less in official documents double-checked and based on primary crime evidence but are unavoidable in our type of analysis.
7. Language barriers. We decided for a worldwide search of cannibalism cases, which allowed us amassing a large sample, but led us to encounter language problems. In several instances we used tools such as Google Translate to check local news sources. Such tools are powerful, but imperfect.

Strengths of Our Approach

1. Numbers. The biggest strength of the worldwide internet-based search for cannibalistic homicides is the sheer number of cases it returns.
2. Substantial coverage. The news coverage of cannibalistic cases is substantial. In a contemporary society, it is therefore simply unlikely that a cannibalistic homicide is not covered, unless (a specific detail of) a case is prohibited to be covered by the press.
3. Rich detail. Our data set contains very detailed information about cannibalistic homicides.
4. Good estimates. A lot of the evidence presented here is inferential, but many of the estimates presented here are good estimates. In modern societies an immense amount of effort is made to clear up homicides. Thus, a lot of the estimates about the deeds of serial murderers presented come from police investigators, who spent years of their life chasing the perpetrators; such detailed police work entitles to estimates about the deeds of offenders.
5. Documentation effort in internet-data sets. A lot of our searches and results rely on pages like and lists of cannibalistic incidents. Many of these data sets do not comply with strict scientific standards of referencing; nevertheless, it would be a mistake to underestimate the effort and expertise that went into aggregating these data sets.
6. Access to rare cases. Cannibalistic homicides are rare and if one wants to investigate subclasses of such cases (i.e., very rare cases) the comprehensive search strategy is indispensable.
7. Informal cross validation. Whenever possible we informally cross-validated data sets against each other.
Our results indicate that cannibalistic homicide is a distinctive offense with a special pattern of murder methods, a strong relation to sexual acts, distinctive patterns of victims and offenders, and unique victim-offender relationships. There is a seemingly high amount of kin-avoidance in such crimes, in particular, if offenders do not suffer from serious mental health problems. We suggest that kin-avoidance and spitting out of conspecifics might be triggered by internally generated disgust against kin-ingestion.

Social status is a universal and consequential dimension of variation within human groups; multiple prominent theories have been proposed to explain how status is allocated

Psychological foundations of human status allocation. Patrick K. Durkee, Aaron W. Lukaszewski, and David M. Buss. Proceedings of the National Academy of Sciences, August 18, 2020.

Significance: Social status is a universal and consequential dimension of variation within human groups. Multiple prominent theories have been proposed to explain how status is allocated, but extant evidence is insufficient to adjudicate between their conflicting predictions. Here we show that distinctions between each theory hinge on the relative importance of four key affordance dimensions: benefit-generation ability, benefit-generation willingness, cost-infliction ability, and cost-infliction willingness. Each theory makes a different prediction about the role of each affordance in status allocation. We test these competing predictions to explain status allocations across 14 nations. We found that benefit-generation affordances uniquely predicted status allocations across nations, whereas cost-infliction affordances were weak or null competing predictors.

Abstract: Competing theories of status allocation posit divergent conceptual foundations upon which human status hierarchies are built. We argue that the three prominent theories of status allocation—competence-based models, conflict-based models, and dual-pathway models—can be distinguished by the importance that they place on four key affordance dimensions: benefit-generation ability, benefit-generation willingness, cost-infliction ability, and cost-infliction willingness. In the current study, we test competing theoretical predictions about the relative centrality of each affordance dimension to clarify the foundations of human status allocation. We examined the extent to which American raters’ (n = 515) perceptions of the benefit-generation and cost-infliction affordances of 240 personal characteristics predict the status impacts of those same personal characteristics as determined by separate groups of raters (n = 2,751) across 14 nations. Benefit-generation and cost-infliction affordances were both positively associated with status allocation at the zero-order level. However, the unique effects of benefit-generation affordances explained most of the variance in status allocation when competing with cost-infliction affordances, whereas cost-infliction affordances were weak or null predictors. This finding suggests that inflicting costs without generating benefits does not reliably increase status in the minds of others among established human groups around the world. Overall, the findings bolster competence-based theories of status allocation but offer little support for conflict-based and dual-pathway models.

Keywords: statushierarchyaffordancesdominanceprestige

Nostalgia is a bittersweet emotion, but more sweet than bitter

The Hedonic Character of Nostalgia: An Integrative Data Analysis. Joost Leunissen et al. Emotion Review, August 30, 2020.

Abstract: We conducted an integrative data analysis to examine the hedonic character of nostalgia. We combined positive and negative affect measures from 41 experiments manipulating nostalgia (N = 4,659). Overall, nostalgia inductions increased positive and ambivalent affect, but did not significantly alter negative affect. The magnitude of nostalgia’s effects varied markedly across different experimental inductions of the emotion. The hedonic character of nostalgia, then, depends on how the emotion is elicited and the benchmark (i.e., control condition) to which it is compared. We discuss implications for theory and research on nostalgia and emotions in general.

Keywords: ambivalence, integrative data analysis, negative affect, nostalgia, positive affect

Ambivalence and the Function of Nostalgia

The ambivalent hedonic character of nostalgia can provide
clues to its functional value. The dynamic model of affect
(Zautra et al., 2000) and the coactivation model of health (J. T.
Larsen et al., 2003) point to the resilience and coping functions
of ambivalent affect. According to the dynamic model of affect,
positive and negative affect function to provide information
about one’s immediate environment that is relevant to one’s
well-being. In calm and predictable times, positive and negative
affect are relatively independent. However, during times of
stress, an attentional shift occurs where negative affect gains
priority, resulting in a stronger inverse association between positive
and negative affect (Davis et al., 2004; Zautra et al., 2002).
The key to maintaining psychological well-being during times
of stress is the “uncoupling” of positive and negative affect
(Reich et al., 2003, p. 77). This uncoupling allows one to experience
positive and negative affect simultaneously, and this emotional
complexity is a key driver to cope with stressful life
circumstances. For example, dispositional resilience is positively
associated with emotional ambivalence (Ong &
Bergeman, 2004), emotional ambivalence is positively associated
with resilience during bereavement (Coifman et al., 2007),
and emotional ambivalence is positively associated with psychological
well-being during psychotherapy (Adler &
Hershfield, 2012). The coactivation model of health similarly
proposes that ambivalent affect facilitates coping with stressful
life events (J. T. Larsen et al., 2003). The results of a 10-year
longitudinal study are consistent with the idea that ambivalent
affect is positively associated with well-being (Hershfield et al.,
2013). The ability to tolerate and harness emotional ambivalence,
then, is a resource for coping with stressful life experiences
(Lindquist & Barrett, 2008; Ong et al., 2009).

Research on the psychological functions of nostalgia dovetails
with the demonstrated benefits of emotional ambivalence.
Ambivalent affect could influence cognitive flexibility (Mejía &
Hooker, 2017; Rothman & Melwani, 2017). Ambivalent affect
facilitates contradictory appraisals of a situation (e.g., certain
and uncertain, under control and not under control). This, in turn,
may activate a wider range of (atypical) information, give awareness
to new priorities, and encourage the pursuit of novel options
(Mejía & Hooker, 2017; Rothman & Melwani, 2017). Indeed,
emotional ambivalence (e.g., recalling an event such as a graduation)
fosters creativity (Fong, 2006). This literature is in line
with findings illustrating that nostalgia boosts inspiration
(Stephan et al., 2015) and creativity (van Tilburg et al., 2015). In
addition, emotional ambivalence (i.e., the blend of positive and
negative emotions) enhances judgmental accuracy (Rees et al.,
2013). Nostalgia may do the same. By extrapolation, nostalgia
may also aid in decision making by reducing susceptibility to
biases such as anchoring, escalation of commitment (Rothman &
Melwani, 2017), or risk aversion (Zou et al., 2019).

Nostalgia is triggered by stressful experiences, such as loneliness
(Zhou et al., 2008), meaninglessness (Routledge et al.,
2011), and identity discontinuity (Sedikides, Wildschut,
Routledge, & Arndt, 2015). In turn, nostalgia restores a sense of
social connectedness (Sedikides & Wildschut, 2019; Wildschut
et al., 2011), meaningfulness (Leunissen et al., 2018; Sedikides
& Wildschut, 2018), and identity continuity (Sedikides et al.,
2016; van Tilburg, Sedikides, et al., 2019). Nostalgia has a similar
function in the workplace, counteracting the deleterious
effects of low procedural justice on cooperation (van Dijke
et al., 2015), and the detrimental effects of low interactional justice
on intrinsic motivation (van Dijke et al., 2019). In all, the
extant literature supports the notion that nostalgia acts as a coping
resource for stressful life experiences. A key direction for
future research is to substantiate the postulated role of affective
ambivalence in mediating nostalgia’s capacity to enhance cognitive
flexibility and foster resilience to adversity. Testing such
mediational models poses theoretical and methodological challenges
(Spencer et al., 2005), not least because the effect of nostalgia
on affective ambivalence was relatively small, even at its
strongest point (i.e., in ERT experiments). Nevertheless, even
small, short-term effects can produce larger, long-term benefits
(Cohen & Sherman, 2014; Walton & Wilson, 2018).

Sunday, August 30, 2020

Voters seem to react more to relatively smaller scandals by high-quality officials compared to low-quality ones

Strategic Opposition Research. Benjamin Ogden & Alejandro Medina. Texas A&M University Working Paper, June 2020.

Abstract: We develop a model of strategic opposition research within a campaign. A candidate faces an opponent of unknown relative quality. After observing an unverifiable private signal (e.g., rumor of a scandal), the candidate chooses whether to undertake opposition research, attempting a costly search for verifiable bad news, and then whether to reveal what the research found to the voters. Increasing the ex-ante quality of an opponent deters opposition research, but also increases voter response to any given revelation in equilibrium because the voter knows the (unobserved) private signal was sufficient to launch research. This "Halo Effect" can explain both why voters seem to react more to relatively smaller scandals by high-quality officials compared to low-quality ones, and why even high-quality challengers may want to raise the cost of searching their backgrounds, despite their expected lack of scandal. This effect may be sufficiently strong that parties prefer lower expected quality candidates on average. These results also rationalize the mixed empirical literature showing that exogenously generated negative information about candidates (i.e., experiments) tend to show smaller effects on voter behavior than endogenously generated negative information over the course of campaigns (i.e., surveys).

Behavioral Response to Increased Pedestrian and Staying Activity in Public Space: Men may be more likely to be attracted to places with more public users, while females may be less likely to stay

The Behavioral Response to Increased Pedestrian and Staying Activity in Public Space: A Field Experiment. Oscar Zapata and Jordi Honey-Rosés. Environment and Behavior 1 –22. Aug 2020. DOI: 10.1177/0013916520953147

Abstract: William Whyte originally hypothesized that the presence of people in a public space would attract more people. Contemporary planners now refer to “sticky streets” as places where pedestrians are compelled to linger and enjoy vibrant public life. We test the hypothesis that adding users to a public space will attract more people using an experimental design with confederates to add pedestrian movement and staying activity in a residential street for 45 randomly selected hours. We observed staying behavior by gender with and without our intervention. We find that the addition of public users reduced the total number of people staying in our study area, especially among women. We find that women’s right to the city may be constrained by the mere presence of other individuals, even in safe spaces and during daylight hours. Our findings suggest that Whyte’s claim is not universal, but depends on the conditions of a particular site.

Keywords: behavior, field experiment, gender, public life study, public space, urban design

In sum, our results suggest that increasing the number of users in public space has a differentiated effect among males and females. On average, men may be more likely to be attracted to places with more public users, while females may be less likely to stay. However, the difference in number of people staying in the public space is statistically significant only among women. We do not find evidence that the addition of public users increased total staying behavior.

Since the work of Jane Jacobs (1961) and William H. Whyte (1980), urban-ists have thought carefully about how to entice people to stay in well-designed urban plazas, parks and streets. With the work of Jan Gehl and others, the study of public life has emerged as a distinct subfield, with its own methods and tools (Ciocoletto, 2014; Gehl & Svarre, 2013). A major premise of research on public life is that people attract other people. More than anything else, people enjoy watching other people (Toderian, 2014). Well-designed spaces are those that succeed at enticing others to linger, stay longer and in this way, help to build vibrant and inclusive communities. The presence or absence of people in a public space may be interpreted as an indicator of its quality, and these ideas have influenced the design of public spaces, such as plazas, parks, and streets.
We examined the behavioral effect of adding more people to a pedestrian-ized street in a residential community. We test the hypothesis that adding people to the public space might make it more attractive to others. We con-ducted our experiment in a high-quality and pedestrianized street that offers formal and informal seating. We find that the addition of public users reduced the total number of people staying in our study area, especially among women.We observe a strong differential effect by gender in which adding people to a space may invite more males while simultaneously push away females. Our results show that women and men perceive public space differently, and these different perceptions translate into different behavioral responses. We find additional evidence that women’s right to the city is restricted in comparison to men’s. Importantly, this remains true even in high-quality, pedestrianized and safe places. This suggests that gendered spaces are not limited to those areas that are clearly perceived to be unsafe, poorly lit, or otherwise perceived as dangerous for women. Rather even in safe spaces, during day-light hours, women’s right to the city may be constrained by the mere presence of other individuals.Our experimental design does not allow us to identify the underlying factors or mechanisms that might explain the gender difference in the use of the public space. However, the literature already identifies the elements that may explain how the experience of the public space is different for men and women. It is clear that perceptions of safety and the opportunities for social interaction in public areas are conditioned by gender.Our results appear to contradict Whyte’s assertion that people attract peo-ple. Yet we cannot refute this claim for all sites and conditions. Whether our findings would hold in public spaces that are more social in nature, such as plazas or commercial streets, remains an open question. At the very least, we find that Whyte’s claim is not universal, but depends on the conditions of a particular site. It is possible that the particular geometry or conditions of our study site may have contributed to the observed results.

Our results bolster Whyte’s claim that people have an intuitive sense of the carrying capacity of a public space. In his observational work, he noticed that each site had a maximum number of people that it would support, and people would intuitively move somewhere else once that level had been reached. It appears that our intervention reached or surpassed the intuitive carrying capacity of our site. It also seems that men and women perceive density differently, and consequently have different density thresholds regarding what density levels are tolerable. In short, our results are consistent with Whyte’s notion of carrying capacity but there are likely to be differences between genders on what the intuitive carrying capacity might be.

We are intrigued by Whyte’s notion that we have an intuitive sense of the right number of people is to occupy a space. As noted, this intuitive notion is contingent on gender, but probably other cultural notions and tastes as well. It is also possible that these cultural notions or our perceptions of safety in public space might be evolving, potentially as a result of changing norms or our use of technology in public space. For example, an underlying assumption driving the sticky streets hypothesis is that we enjoy watching other people. When Whyte studied public users in New York, this was certainly true, and people watching was a New York pastime. Surveys of visitors to Central Park in 1982 showed that people watching was the most popular passive activity in Central Park, followed by relaxation, thinking and reading (Barlow Rogers, 1987). Times have changed and perhaps emerging cultural norms are less tolerant of people watching behavior than in the past. Younger generations may feel less comfortable with watching others or being watched, resulting in different behavioral responses to others in public space. If indeed there are changing cultural norms, we would expect to observe these differences by age (Aoki & Downes, 2003). We did not include age in our head-counts of staying behavior, leaving this unresolved in our study. Does the behavioral response of increasing pedestrian and staying behavior have het-erogenous effects by age as well as by gender? Are younger generations less interested in people watching and more attracted to the use of electronic devices? Our results merely raise more questions about under which conditions would we observe different effects. How can planners estimate or predict the carrying capacity of a particular site? What simple design interventions may increase or decrease perceived carrying capacity? What can be done to reduce the gender gap in terms of perception of safety, sense of belonging and staying behavior?

More work is needed to identify the factors that explain people’s decisions around the use of public space. It would be particularly useful to have meth-ods for estimating the carrying capacity of particular sites, as Whyte suggests, or the characteristics of spaces that may make adding people tolerable or desirable. It may also be worth considering how experimental designs may assist in answering these questions. Field experiments on questions about public space remain rare, yet have untapped potential. Field experiments may complement other research methods that aim to understand individual choices, movements and staying behavior in public. Learning when and why certain places are attractive and welcoming to both women and men will provide valuable insights for the theory and practice of urban design and planning.

In relation to heterosexual and homosexual women and men, bisexual women and men appear to experience less sexual satisfaction

Björkenstam C, Mannheimer L, Löfström M, et al. Sexual Orientation–Related Differences in Sexual Satisfaction and Sexual Problems—A Population-Based Study in Sweden. J Sex Med 2020;XX:XXX–XXX.

Introduction Human sexuality is a natural and important part of peoples’ life and well-being. The underlying interactions affecting sexual satisfaction are complex, and sexual orientation differences partly remain to be identified as well as explained.

Aim Our aim was to investigate sexual orientation–related differences in sexual satisfaction and sexual dissatisfaction and differences in sexual function and sexual-related problems.

Methods We used Swedish data from SRHR2017 (sexual and reproductive health and rights), based on self-administered surveys, linked to nationwide registers. The national sample consisted of 14,537 women and men aged 16–84 years. With logistic regression, we examined sexual orientation–related differences in self-reported sexual satisfaction and sexual dissatisfaction, stratified by sex.

Main outcome measures The main outcome measures of this study are odds ratios (ORs) with 95% confidence intervals (CIs).

Results Bisexual women were more dissatisfied with their sex life, as compared with heterosexual women (OR: 1.8; 95% CI: 1.3–2.6), as were bisexual men compared with heterosexual men (OR: 2.7; 95% CI: 1.7–4.4). A bisexual or lesbian identity was a robust risk factor for premature orgasm (OR: 2.1; 95% CI: 1.1–3.9 and OR: 8.0; 95% CI: 3.2–20.0, respectively). Lesbian women seemed to have lower risk for many sexual-related problems (however not significant). Gay men lacked arousal (OR: 3.3; 95% CI: 1.6–6.9), had no orgasm (OR: 2.6; 95% CI: 1.4–4.7), and were at lower risk of experiencing premature ejaculation (OR: 0.4; 95% CI: 0.2–0.9), as compared with heterosexual men.

Conclusion Our findings contribute to the sparse evidence of some sexual orientation differences in sexual satisfaction and sexual dysfunctions. Especially bisexual women and men appear to experience less sexual satisfaction in relation to heterosexual and homosexual women and men.

Key Words: LBGTSexualitySexual DysfunctionsSwedenPopulation-Based Survey

Low-ranking Group Members Are Perceived as the Best Sources of Group Norms from the assumption that lower-ranking team members are more attentive to and aware of the descriptive norms

Dannals, Jennifer E., Emily Reit, and Dale T. Miller. 2020. “From Whom Do We Learn Group Norms? Low-ranking Group Members Are Perceived as the Best Sources.” PsyArXiv. August 29. doi:10.31234/

Abstract: Social norm perception is ubiquitous in small groups and teams, but how individuals approach this process is not well understood. When individuals wish to perceive descriptive social norms in a group or team, whose ad- vice and behavior do they prefer to rely on? Four lab studies and one Teld survey demonstrate that when individuals seek information about a team’s social norms they prefer to receive advice from lower-ranking individuals (Studies 1–4) and give greater weight to the observed behavior of lower-ranking individuals (Study 5). Results from correlation (Study 3) and moderation (Study 4) approaches suggest this preference stems from the assumption that lower-ranking team members are more attentive to and aware of the descriptive social norms of their team. Alternative mechanisms (e.g., perceived similarity to lower-ranking team members, greater honesty of lower-ranking team members) were also examined, but no support for these was found.

Saturday, August 29, 2020

Humans in specific instances are psychologically prepared to prioritize misinformation over truth to, inter alia, mobilize the ingroup against the outgroup & signal commitment to the group to fellow ingroup members

Petersen, Michael Bang, Mathias Osmundsen, and John Tooby. 2020. “The Evolutionary Psychology of Conflict and the Functions of Falsehood.” PsyArXiv. August 29. doi:10.31234/

Abstract: Truth is commonly viewed as the first causality of war. As such the current circulation of fake news, conspiracy theories and other hostile political rumors is not a unique phenomenon but merely another example of how people are motivated to dispend with truth in situations of conflict. In this chapter, we theorize about the potentially evolved roots of this motivation and outline the structure of the underlying psychology. Specifically, we focus on how the occurrence of intergroup conflict throughout human evolutionary history has built psychological motivations into the human mind to spread information that (a) mobilize the ingroup against the outgroup, (b) facilitate the coordination of attention within the group and (c) signal commitment to the group to fellow ingroup members. In all these instances, we argue, human psychology is designed to select information that accomplishes these goals most efficiently rather than to select information on the basis of its veracity. Accordingly, we hypothesize that humans in specific instances are psychologically prepared to prioritize misinformation over truth.

Check also Echo Chambers Exist! (But They're Full of Opposing Views). Jonathan Bright, Nahema Marchal, Bharath Ganesh, Stevan Rudinac. arXiv Jan 30 2020. arXiv:2001.11461.

And: The rise in the political polarization in recent decades is not accounted for by the dramatic rise in internet use; claims that partisans inhabit wildly segregated echo chambers/filter bubbles are largely overstated:
Deri, Sebastian. 2019. “Internet Use and Political Polarization: A Review.” PsyArXiv. November 6.

And Testing popular news discourse on the “echo chamber” effect: Does political polarisation occur among those relying on social media as their primary politics news source? Nguyen, A. and Vu, H.T. First Monday, 24 (5), 6. Jun 4 2019.

Check also
Why Smart People Are Vulnerable to Putting Tribe Before Truth. Dan M Kahan. Scientific American, Dec 03 2018.

Baum, J., Rabovsky, M., Rose, S. B., & Abdel Rahman, R. (2018). Clear judgments based on unclear evidence: Person evaluation is strongly influenced by untrustworthy gossip. Emotion,

The key mechanism that generates scientific polarization involves treating evidence generated by other agents as uncertain when their beliefs are relatively different from one’s own:

Scientific polarization. Cailin O’Connor, James Owen Weatherall. European Journal for Philosophy of Science. October 2018, Volume 8, Issue 3, pp 855–875.

Polarized Mass or Polarized Few? Assessing the Parallel Rise of Survey Nonresponse and Measures of Polarization. Amnon Cavari and Guy Freedman. The Journal of Politics,

Tappin, Ben M., and Ryan McKay. 2018. “Moral Polarization and Out-party Hate in the US Political Context.” PsyArXiv. November 2.

Forecasting tournaments, epistemic humility and attitude depolarization. Barbara Mellers, PhilipTetlock, Hal R. Arkes. Cognition,

Does residential sorting explain geographic polarization? Gregory J. Martin & Steven W. Webster. Political Science Research and Methods,

Liberals and conservatives have mainly moved further apart on a wide variety of policy issues; the divergence is substantial quantitatively and in its plausible political impact: intra party moderation has become increasingly unlikely:

Peltzman, Sam, Polarizing Currents within Purple America (August 20, 2018). SSRN:

Does Having a Political Discussion Help or Hurt Intergroup Perceptions? Drawing Guidance From Social Identity Theory and the Contact Hypothesis. Robert M. Bond, Hillary C. Shulman, Michael Gilbert. Bond Vol 12 (2018),

All the interactions took the form of subjects rating stories offering ‘ammunition’ for their own side of the controversial issue as possessing greater intrinsic news importance:

Perceptions of newsworthiness are contaminated by a political usefulness bias. Harold Pashler, Gail Heriot. Royal Society Open Science,

When do we care about political neutrality? The hypocritical nature of reaction to political bias. Omer Yair, Raanan Sulitzeanu-Kenan. PLOS,

Democrats & Republicans were both more likely to believe news about the value-upholding behavior of their in-group or the value-undermining behavior of their out-group; Republicans were more likely to believe & want to share apolitical fake news:

Pereira, Andrea, and Jay Van Bavel. 2018. “Identity Concerns Drive Belief in Fake News.” PsyArXiv. September 11.

In self-judgment, the "best option illusion" leads to Dunning-Kruger (failure to recognize our own incompetence). In social judgment, it leads to the Cassandra quandary (failure to identify when another person’s competence exceeds our own): The best option illusion in self and social assessment. David Dunning. Self and Identity,

People are more inaccurate when forecasting their own future prospects than when forecasting others, in part the result of biased visual experience. People orient visual attention and resolve visual ambiguity in ways that support self-interests: "Visual experience in self and social judgment: How a biased majority claim a superior minority." Emily Balcetis & Stephanie A. Cardenas. Self and Identity,

Can we change our biased minds? Michael Gross. Current Biology, Volume 27, Issue 20, 23 October 2017, Pages R1089–R1091.
Summary: A simple test taken by millions of people reveals that virtually everybody has implicit biases that they are unaware of and that may clash with their explicit beliefs. From policing to scientific publishing, all activities that deal with people are at risk of making wrong decisions due to bias. Raising awareness is the first step towards improving the outcomes.

People believe that future others' preferences and beliefs will change to align with their own:
The Belief in a Favorable Future. Todd Rogers, Don Moore and Michael Norton. Psychological Science, Volume 28, issue 9, page(s): 1290-1301,

Kahan, Dan M. and Landrum, Asheley and Carpenter, Katie and Helft, Laura and Jamieson, Kathleen Hall, Science Curiosity and Political Information Processing (August 1, 2016). Advances in Political Psychology, Forthcoming; Yale Law & Economics Research Paper No. 561. Available at SSRN:
Abstract: This paper describes evidence suggesting that science curiosity counteracts politically biased information processing. This finding is in tension with two bodies of research. The first casts doubt on the existence of “curiosity” as a measurable disposition. The other suggests that individual differences in cognition related to science comprehension - of which science curiosity, if it exists, would presumably be one - do not mitigate politically biased information processing but instead aggravate it. The paper describes the scale-development strategy employed to overcome the problems associated with measuring science curiosity. It also reports data, observational and experimental, showing that science curiosity promotes open-minded engagement with information that is contrary to individuals’ political predispositions. We conclude by identifying a series of concrete research questions posed by these results.

Facebook news and (de)polarization: reinforcing spirals in the 2016 US election. Michael A. Beam, Myiah J. Hutchens & Jay D. Hmielowski. Information, Communication & Society,

The Partisan Brain: An Identity-Based Model of Political Belief. Jay J. Van Bavel, Andrea Pereira. Trends in Cognitive Sciences,

The Parties in our Heads: Misperceptions About Party Composition and Their Consequences. Douglas J. Ahler, Gaurav Sood. Aug 2017,

The echo chamber is overstated: the moderating effect of political interest and diverse media. Elizabeth Dubois & Grant Blank. Information, Communication & Society,

Processing political misinformation: comprehending the Trump phenomenon. Briony Swire, Adam J. Berinsky, Stephan Lewandowsky, Ullrich K. H. Ecker. Royal Society Open Science, published on-line March 01 2017. DOI: 10.1098/rsos.160802,

Competing cues: Older adults rely on knowledge in the face of fluency. By Brashier, Nadia M.; Umanath, Sharda; Cabeza, Roberto; Marsh, Elizabeth J. Psychology and Aging, Vol 32(4), Jun 2017, 331-337.

Stanley, M. L., Dougherty, A. M., Yang, B. W., Henne, P., & De Brigard, F. (2017). Reasons Probably Won’t Change Your Mind: The Role of Reasons in Revising Moral Decisions. Journal of Experimental Psychology: General.

Science Denial Across the Political Divide — Liberals and Conservatives Are Similarly Motivated to Deny Attitude-Inconsistent Science. Anthony N. Washburn, Linda J. Skitka. Social Psychological and Personality Science, 10.1177/1948550617731500.

Biased Policy Professionals. Sheheryar Banuri, Stefan Dercon, and Varun Gauri. World Bank Policy Research Working Paper 8113.

Dispelling the Myth: Training in Education or Neuroscience Decreases but Does Not Eliminate Beliefs in Neuromyths. Kelly Macdonald et al. Frontiers in Psychology, Aug 10 2017.

Individuals with greater science literacy and education have more polarized beliefs on controversial science topics. Caitlin Drummond and Baruch Fischhoff. Proceedings of the National Academy of Sciences, vol. 114 no. 36, pp 9587–9592, doi: 10.1073/pnas.1704882114,

Expert ability can actually impair the accuracy of expert perception when judging others' performance: Adaptation and fallibility in experts' judgments of novice performers. By Larson, J. S., & Billeter, D. M. (2017). Journal of Experimental Psychology: Learning, Memory, and Cognition, 43(2), 271–288.

Public Perceptions of Partisan Selective Exposure. Perryman, Mallory R. The University of Wisconsin - Madison, ProQuest Dissertations Publishing, 2017. 10607943.

The Myth of Partisan Selective Exposure: A Portrait of the Online Political News Audience. Jacob L. Nelson, and James G. Webster. Social Media + Society,

Echo Chamber? What Echo Chamber? Reviewing the Evidence. Axel Bruns. Future of Journalism 2017 Conference.

Fake news and post-truth pronouncements in general and in early human development. Victor Grech. Early Human Development,

Consumption of fake news is a consequence, not a cause of their readers’ voting preferences. Kahan, Dan M., Misinformation and Identity-Protective Cognition (October 2, 2017). Social Science Research Network,

Twitter: While partisan opinion leaders are certainly polarized, centrist/non-political voices are much more likely to produce the most visible information; & there is little evidence of echo-chambers in consumption
Mukerjee, Subhayan, Kokil Jaidka, and Yphtach Lelkes. 2020. “The Ideological Landscape of Twitter: Comparing the Production Versus Consumption of Information on the Platform.” OSF Preprints. June 23.

Contrary to this prediction, we found that moderate and uncertain participants showed a nonreciprocal attraction towards extreme and confident individuals:
Zimmerman, Federico, Gerry Garbulsky, Dan Ariely, Mariano Sigman, and Joaquin Navajas. 2020. “The Nonreciprocal and Polarizing Nature of Interpersonal Attraction in Political Discussions.” PsyArXiv. August 21.