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Sunday, January 26, 2020

When Deliberation Produces Persuasion rather than Polarization: Measuring and modeling Small Group Dynamics in a Field Experiment

When Deliberation Produces Persuasion rather than Polarization: Measuring and modeling Small Group Dynamics in a Field Experiment. Kevin Esterling, Archon Fung & Taeku Lee. British Journal of Political Science, Dec 2019,

Abstract: This article proposes a new statistical method to measure persuasion within small groups, and applies this approach to a large-scale randomized deliberative experiment. The authors define the construct of ‘persuasion’ as a change in the systematic component of an individual's preference, separate from measurement error, that results from exposure to interpersonal interaction. Their method separately measures persuasion in a latent (left-right) preference space and in a topic-specific preference space. The model's functional form accommodates tests of substantive hypotheses found in the small-group literature. The article illustrates the measurement method by examining changes in study participants' views on US fiscal policy resulting from the composition of the small discussion groups to which they were randomly assigned. The results are inconsistent with the ‘law of small-group polarization’, the typical result found in small-group research; instead, the authors observe patterns of latent and policy-specific persuasion consistent with the aspirations of deliberation.

Interactive effects of tactile warmth & ambient temperature on the search for social affiliation: In colder ambient environments we report greater loneliness, & pursue both physical warmth & social affiliation

Interactive effects of tactile warmth and ambient temperature on the search for social affiliation. Adam Fay & Jon Maner. Social Psychology, Jan 2020.

Abstract: Laboratory studies have linked variability in temperature to the psychology of social affiliation. In colder ambient environments, for example, people report greater loneliness, and they pursue both physical warmth and social affiliation (i.e., social warmth). Here, a field experiment tested whether tactile warmth eliminates the effect of colder ambient temperatures on desires for social affiliation. Consistent with previous research, people expressed greater intentions to affiliate on colder days. However, tactile warmth eliminated this effect. On colder (but not warmer) days exposure to a tactile warmth manipulation eliminated heightened desires for social affiliation. Findings suggest that seemingly subtle changes in temperature can have important implications for the psychology of social affiliation, and such findings apply to real-world contexts outside the laboratory.

Preferences for conflict & cooperation are systematically different for men & women; the increasing enfranchisement of women, not merely the rise of democracy, is the cause of the democratic peace

The Suffragist Peace. Joslyn N. Barnhart, Allan Dafoe, Elizabeth N. Saunders, Robert F. Trager. , February 21, 2018.

Abstract: Preferences for conflict and cooperation are systematically different for men and women.
At each stage of the escalatory ladder, women prefer more peaceful options. They are less
apt to approve of the use of force and the striking of hard bargains internationally, and
more apt to approve of substantial concessions to preserve peace. They impose higher
audience costs because they are more approving of leaders who simply remain out of
conflicts, but they are also more willing to see their leaders back down than engage in
wars. Unlike men, most women impose audience costs primarily because a leader behaved
aggressively in making a threat, not because the leader endangered the states bargaining
reputation through behaving inconsistently. Many of these differences, and possibly all,
span time periods and national boundaries. Women have been increasingly incorporated
into political decision-making over the last century through suffragist movements, raising
the question of whether these changes have had effects on the conflict behavior of nations
consistent with their large effects in other areas, such as the size and competencies of
governments. We find that the evidence is consistent with the view that the increasing
enfranchisement of women, not merely the rise of democracy itself, is the cause of the
democratic peace.


The results above provide evidence that the divergent preferences of the sexes translate into a
pacifying effect when women’s influence on national politics grows. The magnitude of this correlation
is substantial, on par with the largest effects uncovered in the empirical literature on international
relations. There remains much to understand about these political processes, however. The results
presented above are consistent with greater female influence directly through voting, but perhaps
also consistent with influence exercised through other societal channels whose existence correlates
with female franchise. Another alternative explanation for our findings may be that suffrage is
confounded with liberal institutions and attitudes. While this possibility cannot be fully ruled out,
we have illustrated the shortcomings of the liberal institutions argument in a variety of ways. The
concerns of some scholars about the democratic peace may nevertheless apply to the argument we
make here. To address these, we have shown that our findings are robust to a variety of specifications.
We look forward to further investigation in these areas.
At the individual level, the evidence of a gender gap in so many existing survey experiments
suggests that scholars should explore how men and women respond to different frames or primes.
Such evidence would help illuminate how politicians might frame arguments for war or even choose
to use force in different contexts depending on the constraint of women’s more pacific preferences,
or the necessity of expending political capital to overcome those constraints. The exploration of
heterogeneous treatment effects is beyond the scope of this paper but a logical avenue for future
The links in the aggregation chain from the individual level to national policy and international
interactions are also ripe for further exploration. There are potentially many paths from female
suffrage to women’s preferences influencing national policy and international outcomes. Some might
be direct, for example if interest groups are able to exert direct pressure on politicians; some might
be more indirect, for instance if institutional and electoral incentives in some countries make women
a particularly important voting bloc. In the latter case, politicians may anticipate the reactions
of female voters, either by consciously considering women’s lower baseline preference for war or by
treating it as one of part of a package of preferences. At the level of strategic interaction between
states, process tracing might illuminate whether leaders in one state actively consider the extension
of suffrage in adversary states when engaged in a crisis. More fine-grained analysis of how leaders
seek to accommodate women’s preferences in the wars they do fight could also follow, including an
examination of other dependent variables such as war duration, casualties, or military strategy.
Yet another avenue for future research concerns the potentially differing effects of female enfranchisement and female political leadership. While this study focuses on the former, others have
examined the latter, and some evidence exists that female leaders are more willing to participate
in international conflicts (Dube and Harish 2017). Given the on average individual level differences
between the sexes, this may be considered surprising. Future research should probe the extent to
which this tension is explained by one of two factors. The first is whether female political leaders
are systematically different from female population averages in ways that relate to political decisions
to engage in conflict (Fukuyama 1998, 32). The second is the extent to which female leaders, who
have often been a gender minority among their peers, have been influenced by incentives to mimic or
even exceed the aggressive norms of male peers (Goldstein 2003, 124-5. Doing otherwise might have
been interpreted as a form of “weakness” in the conduct of foreign affairs.33 In effect, as Ehrenreich
(1999) point out, the “tough” international actions of Indira Gandhi and Margaret Thatcher may
have been a form of “male posturing.”34
As the field of international relations has returned to studying individuals and their preferences
over foreign policy and international issues, the long-understood gender gap has been glossed over,
if acknowledged at all. Yet this persistent feature of individual preferences over war and peace
changes the composition of the electorate in states that give women the vote. This article represents
an important step in establishing the link, across space and time, between the gender gap at the
individual level and peace at the international level. Democracy gives the public a voice, but the
public is not homogeneous. This article suggests that women’s preferences exert a significant and
independent effect on state behavior in war, conditional on the existence of political institutions
that allow women’s voices to be heard. Early suffragist movements, including those that successfully
expanded suffrage following the First World War, were closely linked to peace movements (Goldstein
2003, 322-31). They hoped to make world politics more pacific by giving women greater say in
political affairs via the vote; their hopes were fulfilled.

Altruistic behaviors relieve physical pain

Altruistic behaviors relieve physical pain. Yilu Wang et al. PNAS January 14, 2020 117 (2) 950-958.

Significance: For centuries, scientists have pondered why people would incur personal costs to help others and the implications for the performers themselves. While most previous studies have suggested that those who perform altruistic actions receive direct or indirect benefits that could compensate for their cost in the future, we offer another take on how this could be understood. We examine how altruistic behaviors may influence the performers’ instant sensation in unpleasant situations, such as physical pain. We find consistent behavioral and neural evidence that in physically threatening situations acting altruistically can relieve painful feelings in human performers. These findings shed light on the psychological and biological mechanisms underlying human prosocial behavior and provide practical insights into pain management.

Abstract: Engaging in altruistic behaviors is costly, but it contributes to the health and well-being of the performer of such behaviors. The present research offers a take on how this paradox can be understood. Across 2 pilot studies and 3 experiments, we showed a pain-relieving effect of performing altruistic behaviors. Acting altruistically relieved not only acutely induced physical pain among healthy adults but also chronic pain among cancer patients. Using functional MRI, we found that after individuals performed altruistic actions brain activity in the dorsal anterior cingulate cortex and bilateral insula in response to a painful shock was significantly reduced. This reduced pain-induced activation in the right insula was mediated by the neural activity in the ventral medial prefrontal cortex (VMPFC), while the activation of the VMPFC was positively correlated with the performer’s experienced meaningfulness from his or her altruistic behavior. Our findings suggest that incurring personal costs to help others may buffer the performers from unpleasant conditions.

Keywords: altruistic behaviorphysical painmeaningfulnessfunctional MRI

Check also Most research has found that people exhibit altruism towards attractive people, suggesting altruistic behavior is driven by mate choice motivation:
The role of prosocial behaviors in mate choice: A critical review of the literature. Manpal Singh Bhogal, Daniel Farrelly, Niall Galbraith. Current Psychology, May 27 2019.

Supporters of the Republican Party have become much more skeptical of the science of climate change since the 1990s, maybe as a backlash to out-group cues from Democratic elites

Merkley, Eric, and Dominik Stecula. 2020. “Party Cues in the News: Democratic Elites, Republican Backlash and the Dynamics of Climate Skepticism.”  British Journal of Political Science. Preprint January 25. doi:10.31219/

Abstract: Supporters of the Republican Party have become much more skeptical of the science of climate change since the 1990s. We argue that backlash to out-group cues from Democratic elites played an important role in this process. We construct aggregate measures of climate skepticism from nearly 200 public opinion polls at the quarterly level from 2001 to 2014 and at the annual level from 1986 to 2014. We also build time series measures of possible contributors to climate skepticism using an automated media content analysis. Our analyses provide evidence that cues from party elites – especially from Democrats – are associated with aggregate dynamics in climate change skepticism including among supporters of the Republican Party. We then conduct a party cue survey experiment on a sample of 3,000 Americans through Amazon Mechanical Turk to provide more evidence of causality. Together, these results draw attention to the importance of out-group cue-taking and suggest we should see climate change skepticism through the lens of elite-led opinion formation.

Climate scientists, politicians, and political scientists alike have been perplexed that a sizable portion of the American public rejects climate science, particularly among Republican Party supporters. Some have pointed to the role of organized climate denialists and the prevalence of ‘false balance’ in news coverage, others have highlighted the importance of ideology and media framing. Taking a back seat until recently has been the role of party elites. All of these factors could very well influence climate attitudes in the isolation of a survey experiment, but this does not mean they are meaningful drivers of the dynamics of American climate skepticism. We believe scholars need to also examine over time dynamics in the news media environment to examine this question, which has been neglected thus far in research. This paper situates climate change polarization in the larger literature on citizen cue-taking, opinion formation and persuasion. We argue that out-group cues from Democratic elites caused attitudinal backlash among Republican voters, reflected in their growing embrace of climate skepticism. The role of out-group cues in repelling partisan citizens has been less prominent in literature largely focused on persuasion by in-group elites (Cohen 2003; Kam 2005; Mondak 1993), though the importance of out-group elites have recently come to scholarly attention in the United States (Goren et al. 2009; Nicholson 2012). Our study provides more evidence of the central importance of out-group cues on a pressing and important national issue by marshaling a unique combination of text analysis, time series modeling, and experiments. We find that the most consistent factor that predicts aggregate patterns of climate skepticism in the public, and among Republican supporters specifically, are cues from Democratic party elites. We find that Democratic elite cues lead rather than follow public opinion on this topic (H1) and that they are contemporaneously correlated with public opinion even after controlling for other factors scholars have deemed important in shaping attitudes towards climate change (H2). These findings are supported by our survey experiment. We find that polarizing party cues from Democratic (and Republican) elites increase climate skepticism among Republican Party supporters (H3). We found this to be the case with thin treatments and after decades of partisan polarization has already occurred. We did not find a consistently similar effect among Democratic Party supporters, though we must sound a word of caution on this latter point. It is possible these results were hampered by a ceiling effect – Democratic supporters are already very supportive of the climate change consensus, so it is possible our treatments could not move the needle any further. The backlash exhibited by Republican respondents to Democratic elite cues rivals the persuasive
power of in-group cues from Republican elites in our sample, but it also appears to be attenuated by consensus cues signaling agreement between Democratic and Republican elites on climate science and the need for mitigation. In short, we show that the story behind climate change polarization is similar to other political issues of the day: members of the public were exposed to a large volume of partisan messages on climate change as the issue grew in salience – in this case primarily from Democratic elites – and formed their opinions accordingly. This work joins an emerging literature on the role of the media and elite cues in climate change polarization (Carmichael and Brulle 2017; Guber 2013; Merkley and Stecula 2018; Tesler 2017), work showing the persuasive influence of out-group party cues (Berinsky 2009; Bischof and Wagner 2019; Feddersen and Adams 2018; Goren et al. 2009; Nicholson 2012). There are a number of important implications from these findings. First, party elites who strongly identify with the scientific consensus on climate change or other issues must weigh the costs and benefits of aggressively communicating their stance in the mass media. The rising prevalence of party elites in news coverage of climate change was inevitable at some level because of the need for large-scale policy action, but this finding has implications for other scientific issues, such as the safety of genetically modified organisms (GMOs) and vaccines. Efforts to bring these issues into the realm of elite conflict will almost surely lead to polarization as an unanticipated consequence. Second, emphases on ideology and motivated cognition, while important to understanding why persuading Republicans and conservatives about the perils of climate change is a tough task at present, is perhaps of more limited utility in helping us explain how we got to this point in the first place. Republican supporters were not always so skeptical of climate change. They listened to, and formed opinions based on, signals from trusted opinion leaders within their communities. By viewing the roots of climate change skepticism primarily in deep-seated ideological and value constructs, we minimize the degree to which elites can shape those constructs. It also means that these elites can turn the tide by taking climate change out of the realm of hyper-partisan conflict. Although our experiment did not find a de-polarizing effect of a consensus cue treatment, a stronger treatment featuring highly respected Republican officials may have more success. Lastly, and relatedly, the potentially prominent role of party elites in the formation of public attitudes on climate change suggests scholars should invest less time and resources in identifying messaging strategies to mobilize support for the climate consensus, and more on understanding the motivations and behavior of party elites. Finding ways to mobilize an elite consensus across partisan
lines is perhaps the most promising strategy to bring public opinion alongside the scientific consensus on climate change.

It Happened to a Friend of a Friend: Inaccurate Source Reporting in Rumor Diffusion

Altay, Sacha, Nicolas Claidière, and Hugo Mercier. 2020. “It Happened to a Friend of a Friend: Inaccurate Source Reporting in Rumor Diffusion.” PsyArXiv. January 25. doi:10.31234/

Abstract: Culturally successful rumors are commonly attributed to a credible friend of a friend, but little is known about how this sourcing can boost rumors’ propagation. In four online experiments (N = 2024) we found that attribution to a credible friend of a friend increased a rumor’s perceived plausibility, and participants’ willingness to share it. Moreover, the credible friend of a friend attribution remained stable across multiple transmissions, instead of the number of friends mentioned increasing with each transmission. The main alternative was to only mention a friend (without credibility attribution). Even though this latter alternative dominated linear transmission chains, introducing a degree of redundancy allows the credible friend of a friend to persist or dominate. We suggest that the preference for attributing rumors to a credible friend of a friend reflects reputation management considerations.

Many of our smiles in everyday life are only posed and signify something very different from joy and happiness

Emotional expressions in human and non-human great apes. Mariska E. Kret et al. Neuroscience & Biobehavioral Reviews, January 25 2020,

• Emotional expressions are frequently used in all great ape species.
• Compared to apes, humans have evolved communicative faces where all the expressive parts are emphasized.
• Also in great apes species-specific facial characteristics have evolved to enhance communication.
• Smiles have been ritualized to a greater extent in humans than in apes, laughter is similar and seen in comparable contexts.
• Great apes do have voluntary control over some expressions.

Abstract: Humans and great apes are highly social species, and encounter conspecifics throughout their daily lives. During social interactions, they exchange information about their emotional states via expressions through different modalities including the face, body and voice. In this regard, their capacity to express emotions, intentionally or unintentionally, is crucial for them to successfully navigate their social worlds and to bond with group members. Darwin (1872) stressed similarities in how humans and other animals express their emotions, particularly with the great apes. Here, we show that emotional expressions have many conserved, yet also a number of divergent features. Some theorists consider emotional expressions as direct expressions of internal states, implying that they are involuntary, cannot be controlled and are inherently honest. Others see them as more intentional and/ or as indicators of the actor’s future behavior. After reviewing the human and ape literature, we establish an integrative, evolutionary perspective and provide evidence showing that these different viewpoints are not mutually exclusive. Recent insights indicate that, in both apes and humans, some emotional expressions can be controlled or regulated voluntarily, including in the presence of audiences, suggesting modulation by cognitive processes. However, even non-intentional expressions such as pupil dilation can nevertheless inform others and influence future behavior. In sum, while showing deep evolutionary homologies across closely related species, emotional expressions show relevant species variation.

Keywords: emotional expressionsgreat apescomparative psychologycognitive controlevolution

Political leanings are the strongest predictors of climate change beliefs, particularly among the more knowledgeable

Climate Change: A Partisan and Polarized Issue in the United States. Risa Palm, Toby Bolsen. Climate Change and Sea Level Rise in South Florida pp 15-40, January 2 2020.

Abstract: Climate change has become a politically polarized issue within the past 30 years, as interest groups and certain political leaders sought to dispute the growing scientific consensus about its causes and impacts. This chapter synthesizes a large body of survey, experimental and methodological literature that places the empirical study of South Florida in context. Past survey research has shown conclusively that party identification and ideology are the strongest predictors of climate change beliefs of Americans. Other predictors that are less consistent include demographic characteristics, cultural worldviews and personal experience. Survey and laboratory research has been directed at understanding the processes involved in accepting or denying messages about climate change. Among the findings are that strategically framed messages can shift opinion, that a belief in scientific consensus about climate change may increase acceptance of its reality, that prior beliefs, group identities and cultural worldviews moderate the acceptance of climate change information through motivated reasoning, and that best practices involve describing climate change as a personal risk, using social group norms to convince skeptics, and emphasizing social consensus on the issue. Prior research suggests that a message about environmental risk that is local and specific will be relatively more effective, particularly when the immediate threat is already visible.

Keywords: Motivated reasoning Framing Partisanship Public opinion Consensus Polarization Risk communication

Saturday, January 25, 2020

Gun owning women are more engaged & participatory in politics than non-owning women; often feel empowered by owning a gun; & are more supportive of death penalty & military use than non-owners

Female Firepower: Exploring the Politics of Gun Ownership and Gender. Alexandra Terese Middlewood. University of Arkansas, PhD Thesis, May 2019.

Abstract: Pro-gun organizations have made great strides in mobilizing women and have been successful in inculcating women into gun culture. This raises questions about the intersection of gun ownership, an emerging political identity, and gender. Thus, this dissertation explores the cross pressures women face from their gun ownership status and the political consequences of such cleavages using an intersectional approach. First, I examine the effect of gun ownership on women’s political participation and engagement. I find gun owning women to be more engaged and participatory than non-owning women, and find them to be particularly motivated by gun issues. Second, I study the effect of gun ownership on women’s feelings of safety in public spaces where firearms are present. Women often feel empowered by owning a gun, and I find gun owning women to be much less averse to firearms than non-owning women. Furthermore, in some cases, women owners were even less averse than their male counterparts. Lastly, I examine the effect of gun ownership on women’s attitudes about use of force policies, namely the death penalty and the use military force. Here, gun owning women are more supportive of such policies than non-owners, and gun ownership is found to mitigate the expected gender gap in attitudes on these issues. I conclude by addressing the importance of these findings for the literature and for politics, the limitations of these studies, and avenues for future research.

People perform better on a cognitive task when they know its end; asymptotic performance level reflects ability as well as effort-allocation decision

Cognitive performance is enhanced if one knows when the task will end. Maayan Katzir Aviv, Emanuel Nira Liberman. Cognition, Volume 197, April 2020, 104189.

• People perform better on a cognitive task when they know its end.
• Asymptotic performance level reflects ability as well as effort-allocation decision.
• We theorize that opportunity cost (OC) reduces near a salient end-point.
• By reducing OC, salient end-points reduce mental fatigue/experienced effort.

Abstract: In two studies, participants performed a switching task, and we provided to only half of them feedback on goal progress (how much of the task still remains). Importantly, this feedback did not inform participants on how well they performed. We found that participants in the feedback condition achieved a higher asymptotic level of performance, reported less fatigue and took shorter breaks between blocks compared to the control condition. These results suggest that asymptotic level of performance reflects not only ability (as is commonly assumed in the literature) but also motivation. We suggest that when people know when a focal task would end, they invest more effort in it because foregoing other activities becomes less costly (i.e., opportunity cost of engaging in the focal activity decreases) and because knowing when a task would end frees the actor from the need to conserve effort. These results suggest a simple, effective and costless way to improve cognitive performance that may be applied in educational and organizational settings.

Keywords: Effort allocationGoal gradientOpportunity costCognitive resources

The Architect Who Lost the Ability to Imagine: The Cerebral Basis of Visual Imagery After a Cerebral Artery Stoke

Thorudottir, S.; Sigurdardottir, H.M.; Rice, G.E.; Kerry, S.J.; Robotham, R.J.; Leff, A.P.; Starrfelt, R. The Architect Who Lost the Ability to Imagine: The Cerebral Basis of Visual Imagery. Brain Sci. 2020, 10, 59.

Abstract: While the loss of mental imagery following brain lesions was first described more than a century ago, the key cerebral areas involved remain elusive. Here we report neuropsychological data from an architect (PL518) who lost his ability for visual imagery following a bilateral posterior cerebral artery (PCA) stroke. We compare his profile to three other patients with bilateral PCA stroke and another architect with a large PCA lesion confined to the right hemisphere. We also compare structural images of their lesions, aiming to delineate cerebral areas selectively lesioned in acquired aphantasia. When comparing the neuropsychological profile and structural magnetic resonance imaging (MRI) for the aphantasic architect PL518 to patients with either a comparable background (an architect) or bilateral PCA lesions, we find: (1) there is a large overlap of cognitive deficits between patients, with the very notable exception of aphantasia which only occurs in PL518, and (2) there is large overlap of the patients’ lesions. The only areas of selective lesion in PL518 is a small patch in the left fusiform gyrus as well as part of the right lingual gyrus. We suggest that these areas, and perhaps in particular the region in the left fusiform gyrus, play an important role in the cerebral network involved in visual imagery.

Keywords: visual imagery; stroke; posterior cerebral artery; aphantasia; prosopagnosia; visual perception

Trajectories of Migrant Male Sex Workers in Paris: He are too often presented as street-based seller of sexual services whereas many of them actually perform intimacy and companionship

Selling Sex and Intimacy in Paris: Trajectories of Migrant Male Sex Workers. Kostia Lennes. 5th European Geographies of Sexualities Conference, Prague Sep 2019. Ed. Michal Pitoňák, Lukáš Pitoňák.

ABSTRACT: Although further attention has been paid to male sex workers in the past two decades, most scholars who discussed this issue in relation to migration did so through the lens of sex tourism (Allen 2007; Mitchell 2015). In this perspective, male sex workers, who are mostly locals, are therefore excluded from the focus on mobilities. On the other hand, research on migrant sex workers in global cities have focused almost exclusively on women (Chin 2014), with a few notable exceptions (Mai 2018). This proposal aims to fill this gap by presenting the first insights of an ongoing doctoral research project on non-trafficked male sex workers who migrated to Paris in order to perform sexual labour. Coming from different regions of the world, these men have various backgrounds and are often on the move between several cities, in Europe and beyond. Drawing on anthropological accounts on globalisation and cosmopolitanism, the main objective of this research project is to grasp the trajectories of these men who have come to sell sex and intimacy in the French global city. Furthermore, particular attention will be paid to other ways of commodifying intimacy (Constable 2009) than sexual contacts strictly speaking, which is still an overlooked issue as Sanders (2008) and Weitzer (2009) noted. Indeed, the figure of the migrant sex worker is too often presented as a streetbased seller of sexual services whereas many of them actually perform intimacy and companionship, thus redefining contemporary forms of sex work among migrants.

Keywords: male sex workers; cosmopolitanism; commodification of intimacy; sexual labour

The overweight, those carrying a large bag and females avoided both stair climbing and descent more frequently than their comparison groups

Eves FF (2020) When weight is an encumbrance; avoidance of stairs by different demographic groups. PLoS ONE 15(1): e0228044, Jan 24 2020.

Background Locomotion is an energy costly behaviour, particularly when it entails raising weight against gravity. Minimization of locomotor costs appears a universal default. Avoidance of stair climbing helps humans minimise their energetic costs. In public access settings, demographic subgroups that raise more ‘dead’ weight than their comparison groups when climbing are more likely to avoid stairs by choosing the escalator. Individuals who minimise stair costs at work, however, can accumulate a deficit in energy expenditure in daily life with potential implications for weight gain. This paper tests the generality of avoidance of stairs in pedestrians encumbered by additional weight in three studies.

Methods Pedestrian choices for stairs or the alternative were audited by trained observers who coded weight status, presence of large bags and sex for each pedestrian. Sex-specific silhouettes for BMIs of 25 facilitated coding of weight status. Choices between stairs and a lift to ascend and descend were coded in seven buildings (n = 26,981) and at an outdoor city centre site with the same alternatives (n = 7,433). A further study audited choices to ascend when the alternative to stairs was a sloped ramp in two locations (n = 16,297). Analyses employed bootstrapped logistic regression (1000 samples).

Results At work and the city centre site, the overweight, those carrying a large bag and females avoided both stair climbing and descent more frequently than their comparison groups. The final study revealed greater avoidance of stairs in these demographic subgroups when the alternative means of ascent was a sloped ramp.

Discussion Minimization of the physiological costs of transport-related walking biases behaviour towards avoidance of stair usage when an alternative is available. Weight carried is an encumbrance that can deter stair usage during daily life. This minimization of physical activity costs runs counter to public health initiatives to increase activity to improve population health.


As with lifts, avoidance of stairs by choosing a sloped ascent was frequent. The lower rates of avoidance in Chamberlain Square than the station may reflect the greater detour in the square to choose the slope. Avoidance in the square required 76m of walking versus 48.4m for the direct route across the square; at the station, the discrepancy was smaller, 46.1m versus 42.6m. Inevitably, any detour would increase journey times and, typically, pedestrians seek to minimise time and distance [14,15,23,24]. Less frequent avoidance in the square may reflect the greater temporal cost of the indirect route. Nonetheless, stairs are a more energy efficient means of raising weight against gravity than slopes of equivalent angle [29]. Avoiding stairs by choosing a slope will increase both temporal and energetic costs, unlike the reduced costs with mechanised alternatives. This result of avoidance, despite increased cost, may reflect the more gradual force production possible on the slope to achieve the ascent; the actual height of the climb was the same for both alternatives.

General discussion

The studies in this paper reveal consistent effects of demographic grouping on stair avoidance when an alternative is available. In workplaces, and at an outdoor site where the alternative was a lift, overweight pedestrians, those carrying large bags and females were more likely to avoid stairs than their comparison groups. In the final study, this pattern of avoidance occurred where the alternative method of ascent was a sloped ramp. Taken together with a previous summary of avoidance with escalators [9], these studies expand on the original question posed by Brownell and co-workers about the effects of weight status on avoidance of stair use [7,8]. Overweight pedestrians negotiating the built environment are more likely to avoid the physical activity of stair use as part of daily life than healthy weight pedestrians. So are females and those carrying large bags. A bias to minimise the costs of active transport provides a plausible explanation for this generality.

Minimizing energetic cost

During locomotion, humans naturally optimise energetic cost. They adopt a step width, step length and step frequency for walking and choose a step length and frequency for running, all of which minimise the total metabolic cost for completion of the behaviour (see [30]). Humans have an optimal speed for walking and running that minimises the energetic cost per unit distance [31,32], as do other animals [33,34]. Minimisation of transport costs may be a universal default. This minimization requires repeated iterations to optimise the behaviour. Minimisation of transport costs is learnt, linked to the changes in the visual consequences of forward motion [30,3538]. All of the above studies were for locomotion on the level. Stair climbing, at two and half times the energetic cost of purposeful walking [2], is a metabolically costly barrier encountered during active transport. A consistent bias for pedestrians to minimise the cost incurred by climbing is evident; in shopping malls where journey time is less of an issue than in stations, 92.4% avoid stairs (n = 355,069 [9]). Raising body weight against gravity is energetically costly and appears to be minimised by other animals [39,40]. Energy expenditure serves three main functions, basal metabolic rate, diet-related expenditure on ingested food, and energy for physical activity [41]. Human basal metabolic rate requires 60% of the recommended daily intake and utilizing food a further 6–12% [41]. At least two thirds of recommended intake are required for these recurrent costs of maintaining function that must be met. The only modifiable part of the equation linking intake and expenditure is the remaining third of intake available for movements of the body; it has been estimated that 89% of these movements involve walking [41]. Transport-related walking has deep evolutionary roots. Minimising the proportion of total intake required for transport would be biologically advantageous [3034].
Nonetheless, the final pair of studies demonstrated that avoidance was not synonymous with minimisation of expenditure. Choosing a sloped ascent increased both temporal and energetic costs. Walking up a slope allows a more gradual force production during the ascent; peak forces at the knee are reduced compared to stairs [28,29]. Similarly, a modified climbing gait in older individuals reduces the forces at the knee and the ankle to a lower proportion of their maximal capacity [42]. Older climbers have reduced resources for climbing and adopt a reduced, and more gradual, increase in force over time for each step [42]. Choosing the slope in the final pair of studies would allow individuals with reduced resources for climbing to maintain output at a lower proportion of total resources, despite increases in energetic and temporal costs. Aggregated avoidance with ramped ascent, 50.1% (95% CI = 49.3, 50.9) exceeded that when the lift was the alternative, 33.5% (95% CI = 33.0, 34.0). Preference for more gradual resource expenditure could increase avoidance when a ramp was available whereas unwillingness to wait for a lift could decrease it.

Perception of stair slope

Recent research on the perception of the slope of stairs provides clues to the mechanisms that may underlie avoidance based on climbing resources. Perception of the angle of hills and stairs is exaggerated in explicit awareness; a 10˚ hill is reported to be about 30˚ and a 23˚ staircase reported to be 45˚ [4345]. In experimental studies, fatigue from an exhausting run [4547], carrying extra weight [46] and depleted glucose resources [48], all result in further exaggerations of reported angle. While effects of experimental demand have been proposed as an alternative explanation [49,50], quasi-experimental studies confirmed effects of depleted resources [51] and additional weight carried [43,52] where demand was absent. Travelers waiting for their trains were recruited to complete an interview about the environment [43,51,52]; there was no experiment. Proffitt argued that perception of slope was ‘embodied’ in that resources for climbing influenced explicit perception [44]. Embodied effects of resources facilitate physical activity choices without individuals having to specifically consider resource availability [44].
Echoing the behavioural differences documented here, overweight pedestrians, those wearing heavy bags and females all reported potential climbs as steeper than their comparison groups [43,4547,51,52]. Estimates of stair steepness scaled by the deadweight of fat mass that would be carried [51]. As noted earlier, females have, on average, a greater percentage of their weight as body fat (25%) than males (12.5%) and hence are encumbered by more deadweight [10]. Consistently, females reported slopes as steeper than males did [43,45,47,49,50]. Further, stairs were reported as steeper by pedestrians who avoided them by choosing the escalator, even when potential effects of demographics were controlled by stratified sampling and statistical adjustment [43]. Perceived steepness appears to be an environmental cue linked to resources that can deter climbing when an alternative is available [43].
At work, the stairs may not be directly visible when a lift is chosen so perception of steepness cannot directly influence choice. Nonetheless, individuals learn about the potential cost of climbing from experience, biasing subsequent choices. As resources change, behaviour, and the associated perception, echo these changes. Body mass is composed of fat free mass and fat mass. Fat free mass that provides resources for climbing was unrelated to perceived steepness [52]. Rather, it was fat mass, i.e. deadweight that must be carried, that was linked to perception [52]. Further, only changes in fat mass, not fat free mass, were related to changes in perception of steepness over a year later [52]. Similar calibration of perception occurred for changes in body size during pregnancy [53] and loss of leg strength with ageing [54]; changes without experience were ineffective [53]. Obese individuals walk less than lean participants, with daily walking distance negatively correlated with body fat [55]. In the only truly experimental study of weight change, increases in body mass, 78% of which was fat, reduced the distance walked equally for healthy and overweight participants [55]; resources changed behaviour. In both longitudinal perception studies, body change over time influenced perception [52,53]. No study has altered perception to change behaviour. The simplest conclusion is that weight carried deters behaviour [55], consistent with the direction of effects in other research [5658]. Avoidance of stairs seems likely to be a consequence of weight carried. The role of learning in this process, and the potential mediator of perception, is unknown.


It is a curiosity that one strength of these data, direct auditing of behaviour, is accompanied by a limitation. Auditing provides matchless accuracy about the actual behaviour performed; accelerometers, for example, cannot identify behaviour. Observational studies of stair use allow a test of the biasing effects of extra weight carried because of the ability to clearly identify the behavioural choice made. Stair climbing is a vigorous member of the family of active transport behaviours. The energetic cost of stair climbing is clear. Work done to raise weight against gravity is relatively independent of the rate of climbing. Height of the climb, not speed, primarily determines cost. Climbing at 60 steps.min-1 required 8.7 METs (Eves & White, unpublished) whereas climbing at almost twice that speed, 110 steps.min-1, cost 9.6 METs [2]. Effects of weight on the lower intensity activity of stair descent here, and on ‘objectively’ measured walking [55], physical activity [57] and sitting time [56], indicate a generalised effect of weight carried on physical activity choices. Nonetheless, auditing will imperfectly measure demographic differences. Sex is generally straightforward but weight status, and the additional weight of a large bag, must be imprecise categories, even when silhouettes optimise coding for weight status [3,21]. The commonality of effects of weight carried on avoidance across different settings, however, does not suggest imprecision in measurement has impeded the research. The fact that demographic differences in avoidance behaviour are linked to perception of an environmental cue that promotes avoidance indicates some triangulation on the question.

Capacity of cognitive control's estimated heritability was 0.66, & shared & non-shared environmental influences were 0.18 and 0.16; CCC was significantly correlated to higher-level cognition

Accessing the development and heritability of the capacity of cognitive control. Yu Chen et al.
Neuropsychologia, January 24 2020, 107361,

• We examined the developmental course of the capacity of cognitive control (CCC) from early childhood to late adolescence and the heritability of the CCC.
• The CCC increases from the age of 6 years and reaches 95% capacity at 21 years with declined growth rate as a function of age.
• The CCC is highly heritable with an estimated heritability of 0.64.

Cognitive control serves as a core construct, with limited capacity, to support executive functions and other higher-level mental processes such as intellectual activity. Although previous studies have investigated the development of executive functions during specific age periods, the development of the capacity of cognitive control (CCC) from early childhood to late adolescence and the heritability of the CCC have yet to be delineated. In this study, we estimated the CCC based on the performance of a perceptual decision-making task in monozygotic (n = 95) and dizygotic (n = 81) twin pairs with an age range from 6 to 18 years and in a reference young adult group (n = 41, mean age = 26.15 years). In addition, the intelligence quotient (IQ) of these participants was assessed using the Wechsler Intelligence Scales. We found an increase in the CCC from 1.55 bits per second (bps) at age 6 years to its 95% capacity of 3.87 bps at age 21 years, with a reduced growth rate as a function of age. The estimated heritability of the CCC was 0.66, and shared and non-shared environmental influences on the CCC were 0.18 and 0.16, respectively. In addition, the CCC was significantly correlated to IQ. These findings indicate that the CCC is developed throughout the school years, is highly heritable, and is associated with higher-level cognition.

Keywords: Cognitive controlDevelopmentHeritabilityIntellectual abilityThe capacity of cognitive control

Tests of mechanisms of behavior change intervention are not routinely conducted; intervention study quality is sub-optimal; limited data is available on the efficacy of many behavior change techniques

Hagger, Martin S., Susette Moyers, Kaylyn McAnally, and Lauren Mckinley. 2020. “Known Knowns and Known Unknowns on Behavior Change Interventions and Mechanisms of Action.” PsyArXiv. January 24. doi:10.1080/17437199.2020.1719184

Abstract: Systematic reviews and meta-analyses of research play an important role in summarizing current knowledge on the efficacy of the behavior change techniques and mechanisms of action that comprise behavioral interventions. The current reviews in the science of behavior change (SOBC) special issue represent a ‘step change’ in evaluating current evidence on behavior change interventions and mechanisms. This concluding article outlines the key findings and emerging issues identified in the reviews (‘known knowns’), and summarizes the evidence gaps highlighted by the reviews that need to be addressed in future research (‘known unknowns’). Specifically, findings of the reviews indicate that: tests of mechanisms of behavior change intervention are not routinely conducted by primary studies and research syntheses; intervention study quality is sub-optimal and reviews do not sufficiently account for study quality when assessing intervention effects and mechanisms; substantive variability exists in descriptions of intervention content and putative mediators implicated in their mechanisms of action; limited data is available on the efficacy of many behavior change techniques; and moderators of intervention effects and mechanisms are seldom taken into account. In terms of potential solutions to these issues, we advocate: testing isolated effects of behavior change techniques and associated mechanisms of action; routine evaluation of study quality in behavioral intervention research; development of an evidence base of links between behavior change techniques and theory-based constructs involved in mechanisms of action; adoption of fit-for-purpose methods for synthesizing behavioral intervention mechanisms of action; and routine testing of moderators in intervention research.

We label others as straight more often than gay; one reason is a motivated reasoning process that avoids applying stigmatizing labels, because heavy consequences can befall in incorrect gay categorizations

Alt, N. P., Lick, D. J., & Johnson, K. L. (2020). The straight categorization bias: A motivated and altruistic reasoning account. Journal of Personality and Social Psychology, Jan 2020.

Abstract: For 70 years, the field of social perception has concluded that perceivers can determine others’ social category memberships with remarkable accuracy. However, it has become increasingly clear that accuracy is only part of the story, as social category judgments are often systematically biased toward one category over another. For example, when categorizing sexual orientation, perceivers label others as straight more often than gay. This straight categorization bias is reliable, has an effect size larger than that for accuracy, and is not exclusively driven by the low base rate of sexual minorities in the population, yet we know little about its proximal causes. Here, we argue that one facet of this bias is a motivated reasoning process that avoids applying stigmatizing labels to unknown others. Specifically, we propose that perceivers ascribe heavy consequences to incorrect gay categorizations, compelling them to gather and integrate available information in a manner that favors straight categorizations. Studies 1 and 2 tested the dynamic nature of the bias, exploring decision ambivalence and the real-time accrual of visible evidence about a target throughout the perceptual process using mouse-tracking and diffusion modeling. Studies 3–5 tested motivational determinants for the bias, revealing that perceivers associate high costs with incorrect gay categorizations because those errors put other people in harm’s way. Studies 6–9 tested the cognitive mechanisms perceivers engage as they search for information that allows them to avoid costly decision errors. Collectively, these studies provide a new framework for understanding a well-documented but poorly understood response bias in social categorization.

Taiwan: We find that a 10% increase in real estate wealth increases probability of a man getting married in any particular year by 3.92%

Males’ housing wealth and their marriage market advantage. C. Y. Cyrus Chu, Jou-Chun Lin, Wen-Jen Tsay. Journal of Population Economics, January 15 2020.

Abstract: In theory, people who own real estate should have advantage finding a partner in the marriage market. Empirical analyses along this line, however, face three issues. First, it is difficult to identify any causality for whether housing facilitates marriage or expected marriage facilitates a housing purchase. Second, survey samples usually do not cover very wealthy people, and so the observations are top coding in the wealth dimension. Third, getting married is a dynamic life cycle decision, and rich life-history data are rarely available. This paper uses registry data from Taiwan to estimate the impact of males’ housing wealth on their first-marriage duration, taking into account all three issues mentioned above. We find that a 10% increase in real estate wealth increases probability of a man getting married in any particular year by 3.92%. Our finding suggests that housing or real estate is a status good in the marriage market.

Keywords: Marriage formation Housing wealth Status good Duration model

We found that individuals with higher levels of general intelligence exhibited greater openness to using condoms

No glove, no love: General intelligence predicts increased likelihood of condom use in response to HIV threat. Sean T.H.Lee et al. Personality and Individual Differences, Volume 157, 15 April 2020, 109813.

Abstract: Heterosexual intercourse serves the evolutionarily adaptive function of reproduction and gene propagation. However, engaging in sexual intercourse also entails risks in contracting Sexually Transmitted Infections (STIs) that bring about pain and health complications. While STIs typically do not pose a direct threat to one's life, the Human Immunodeficiency Virus (HIV), a relatively recent emergent STI, does. Also, unlike other existing STIs such as Gonorrhea, people infected with HIV typically do not display obvious symptoms that would prompt preventive actions from their sexual partners. Accordingly, consistent condom usage (or lack thereof) has become one of the top concerns of HIV prevention efforts. In this paper, we examine general intelligence, which enables one to cope effectively with evolutionarily novel situations and issues, as a predictor of condom usage in response to the threat of HIV. In Study 1, we found that individuals with higher levels of general intelligence exhibited greater openness to using condoms. In Study 2, we found that individuals with higher levels of general intelligence exhibited greater likelihood of using condoms in a sexual offer scenario—but only when primed with the threat of the evolutionarily novel STI HIV. Implications and future directions are discussed.

Keywords: General intelligenceCondom useHIVEvolutionary psychologyEvolutionary mismatchSavanna-iq interaction hypothesis

Results In a sample of 7,049 men & 7,005 women, being overweight was associated with higher odds of frequent sexual activity among men, but lower odds among women

Grabovac I, Cao C, Haider S, et al. Associations Between Physical Activity, Sedentary Behavior and Weight Status With Sexuality Outcomes: Analyses from National Health and Nutrition Examination Survey. J Sex Med 2020;17:60–68.

Introduction Physical activity is likely to be associated with sexual activity. However, to date, there is no literature on the relationship between overweight/obesity and sexual activity outcomes.

Aim Thus, the present study assessed the associations among physical activity, sedentary behavior, and weight status with sexual activity and number of previous sexual partners in a representative sample of U.S. adults.

Methods Data on leisure time physical activity, total sitting time, weight status, sexual behavior outcomes, and other characteristics were extracted from the National Health and Nutrition Study cycle 2007 to 2016. Logistic regression models were used to evaluate associations among body mass index, leisure time physical activity, and total sitting time with past-year sexual activity and number of sexual partners.

Main Outcome Measure Self reported frequency of past-year sexual activity and number of sex partners in the past year.

Results In a sample of 7,049 men (mean age: 38.3 ± 0.3 years) and 7,005 women (mean age: 38.7 ± 0.2 years) being overweight was associated with higher odds of frequent sexual activity (OR = 1.5; 95% CI = 1.2−1.7) among men, but lower odds among women (OR = 0.8; 95% CI = 0.6−0.9). Sufficient physical activity was associated with higher odds of frequent sexual activity among both men (OR = 1.3; 95% CI = 1.1−1.5) and women (OR = 1.2; 95% CI = 1.0−1.4). In those living alone, being obese was associated with lower odds of having at least 1 sexual partner for men (OR = 0.7; 95% CI = 0.5−0.9) and women (OR = 0.6; 95% CI = 0.4−0.8). Being sufficiently physically active was associated with higher odds of having at least 1 sexual partner only in men (OR = 1.6; 95% CI = 1.2−2.2).

Clinical Implications Healthcare professionals need to be made aware of these results, as they could be used to plan tailored interventions.

Strengths & Limitations Strengths include the large, representative sample of U.S. adults and objective measures of anthropometry. Limitations include the cross-sectional design of the study and that all variables on sexual history were self-reported.

Conclusion The present study identifies novel modifiable behavioral and biological antecedents of sexuality outcomes.

Key Words: Weight StatusSexual ActivityPhysical ActivitySedentary Behavior

Friday, January 24, 2020

Leaders with business experience make smaller contributions to collective defense because they are egoistic and more comfortable relying on a powerful ally for their defense

When Do Leaders Free‐Ride? Business Experience and Contributions to Collective Defense. Matthew Fuhrmann. American Journal of Political Science, January 17 2020.

Abstract: The logic of free‐riding expects that individuals will underinvest in public goods, but people often behave in ways that are inconsistent with this prediction. Why do we observe variation in free‐riding behavior? This study addresses this question by examining contributions to an important international public good—collective defense in military alliances. It develops a behavioral theory of free‐riding in which the beliefs of world leaders are important for explaining investments in public goods. The argument holds that leaders with business experience make smaller contributions to collective defense because they are egoistic and more comfortable relying on a powerful ally for their defense. An analysis of defense expenditures in 17 non‐U.S. members of the North Atlantic Treaty Organization from 1952 to 2014 provides evidence consistent with the theory. The findings suggest that leaders with business experience are more likely than other heads of government to act as self‐interested utility maximizers.

Sex Differences in Misperceptions of Sexual Interest Can Be Explained by Sociosexual Orientation and Men Projecting Their Own Interest Onto Women

Sex Differences in Misperceptions of Sexual Interest Can Be Explained by Sociosexual Orientation and Men Projecting Their Own Interest Onto Women. Anthony J. Lee et al. Psychological Science, January 23, 2020.

Abstract: Sex differences in misperceptions of sexual interest have been well documented; however, it is unclear whether this cognitive bias could be explained by other factors. In the current study, 1,226 participants (586 men, 640 women) participated in a speed-dating task in which they rated their sexual interest in each other as well as the sexual interest they perceived from their partners. Consistent with previous findings, results showed that men tended to overperceive sexual interest from their partners, whereas women tended to underperceive sexual interest. However, this sex difference became negligible when we considered potential mediators, such as the raters’ sociosexual orientation and raters’ tendency to project their own levels of sexual interest onto their partners. These findings challenge the popular notion that sex differences in misperceptions of sexual interest have evolved as a specialized adaptation to different selection pressures in men and women.

Keywords: attraction, sociosexual orientation, speed dating, mean-level bias, tracking accuracy, error-management theory, open data

Sexual Orientation and Cognitive Ability: A Multivariate Meta-Analytic Follow-Up

Sexual Orientation and Cognitive Ability: A Multivariate Meta-Analytic Follow-Up. Yin Xu, Sam Norton, Qazi Rahman. Archives of Sexual Behavior, January 23 2020.

Abstract: A cross-sex shift model of human sexual orientation differences predicts that homosexual men should perform or score in the direction of heterosexual women, and homosexual women in the direction of heterosexual men, in behavioral domains such as cognition and personality. In order to test whether homosexual men and women’s cognitive performance was closer to that of heterosexual men or that of heterosexual women (i.e., sex-atypical for their sex and closer to that of the opposite-sex), we conducted a multivariate meta-analysis based on data from our previous meta-analysis (Xu, Norton, & Rahman, 2017). A subset of this data was used and comprised 30 articles (and 2 unpublished datasets) and 244,434 participants. The multivariate meta-analysis revealed that homosexual men were sex-atypical in mental rotation (Hedges’ g = −0.36) and the water level test (Hedges’ g = −0.55). In mental rotation, homosexual men were in-between heterosexual men and women. There was no significant group difference on spatial location memory. Homosexual men were also sex-atypical on male-favoring spatial-related tasks (Hedges’ g = −0.54), and female-favoring spatial-related tasks (Hedges’ g = 0.38). Homosexual women tended to be sex-typical (similar to heterosexual women). There were no significant group differences on male-favoring “other” tasks or female-favoring verbal-related tasks. Heterosexual men and women differed significantly on female-favoring “other” tasks. These results support the cross-sex shift hypothesis which predicts that homosexual men perform in the direction of heterosexual women in sex differentiated cognitive domains. However, the type of task and cognitive domain tested is critical.

Keywords: Sexual orientation Meta-analysis Sex differences Cognition Spatial Verbal


This analysis produced three main findings. First, homosexual men were sex-atypical in studies measuring mental rotations, the water level test, male-favoring spatial-related tasks, and female-favoring spatial-related tasks. That is, homosexual men’s cognitive performance was closer to that of heterosexual women than heterosexual men. Second, homosexual women were no different to heterosexual women, despite some tendency to be sex-atypical in certain domains (e.g., female-favoring verbal-related tasks). Third, there was considerable heterogeneity in the data as we found in our original meta-analysis.
The magnitude of the effect sizes revealed in the current multivariate meta-analysis was similar to that of our prior univariate meta-analysis. Once again, we found that homosexual men showed a cross-sex shift in male- and female-favoring spatial tasks, which is consistent with our prior demonstration that effect size was the highest for spatial tasks in men (Xu et al., ). The results for women were also consistent with previous work, suggesting that homosexual women are by and large sex-typical in most cognitive domains. However, given that the studies included in the current multivariate meta-analysis are a subsample of those from our prior study, the reduced number of studies may have contributed to the non-significant results found in women.
Our results should not be interpreted as indicating that homosexual men performed exactly the same as heterosexual women. In other words, we find little evidence of a complete sex inversion in this behavioral domain among homosexual men. Task type and cognitive domain are clearly critical. Traditionally, male-favoring spatial tasks (particularly mental rotation and spatial relations) appear to be most sensitive to sexual orientation differences. This is most likely due to the fact that they show robust general sex differences (Voyer et al., ) and that this domain provided the greatest number of studies. The cross-sex shifted pattern displayed by homosexual men is consistent with that found in several other behavioral domains such as sex-typed behavior and personality (Bailey et al., ). However, the effect sizes found here are much smaller than for other traits associated with sexual orientation, such as childhood gender nonconformity (Bailey et al., ).
In general, the body of work supports the prenatal androgen theory which predicts that homosexual men should show cross-sex shifts in sex differentiated behavioral domains in line with the atypical shift in their sexual partner orientation (Ellis & Ames, ). As the present study did not directly measure prenatal androgen levels, caution must be exercised in interpretation. However, some remarks regarding the patterns reported here and their relationship to the prenatal androgen model are worthwhile. The evidence for a cross-sex shift in cognition is inconsistent with research using putative markers of prenatal androgen exposure. For example, digit ratio (2D:4D) is a marker ascribed to the actions of prenatal androgen levels. However, nonheterosexual women have more masculine digit ratios (indicating greater exposure to prenatal androgens) than heterosexual women, but there is no significant difference in digit ratios between heterosexual and nonheterosexual men (Grimbos, Dawood, Burriss, Zucker, & Puts, ). Similarly, differences in handedness are a feature sometimes ascribed to the actions of prenatal testosterone acting on developing brain asymmetries. However, both nonheterosexual men and women are significantly more likely to be non-right-handed than heterosexual men and women rather than cross-sex shifted (Lalumière, Blanchard, & Zucker, ). As mentioned earlier, sexual orientation-related differences in sex-typed behavior (e.g., play and peer preferences), personality, and sexual orientation target preference itself (the preference for males or females as sexual and romantic partners) are much larger than cognitive differences (Bailey et al., ). Some of these traits (sex-typed behaviors) may show substantially larger sex and sexual orientation-related differences during childhood than other traits (cognition). Thus, it is possible that these discrepant findings where some traits show cross-sex shifts (cognition, sex-typed behavior) while others do not (somatic traits), or where cross-sex shifts are found in some traits in females (digit ratio) but not in males, point to a possible patterning of causal pathways by trait, sex, and developmental stage.
As mentioned before, the number and extent of critical periods for prenatal sex hormone actions might be important. There is a growing theoretical suggestion that males may have more than one critical period (e.g., prenatal, early postnatal, and pubertal), while females may have several but longer sustaining “sensitive periods” in which sex hormones and other developmental processes may act over a longer time period to influence behavioral outcomes (McCarthy et al., ). It is important to note that there are no longitudinal studies linking direct measures of prenatal androgens, such as amniotic levels of fetal testosterone, with later sexual orientation and cognition in humans. Such prospective studies would provide the critical test of the prenatal androgen model. Such studies will also need to control for important confounders or third factors such as genetics (e.g., genetic correlations between the traits in question over time). Such third factors might also be more important in the causal association between male sexual orientation and associated behavioral traits. One such factor is the well-known fraternal birth order effect (FBO; Blanchard, ). This refers to the robust finding that homosexual men have more older brothers than heterosexual men, an effect ascribed to maternal immune responses triggered by carrying successive male fetuses which affects sexual differentiation of the brain of later born males (Bogaert et al., ). One study has reported no significant association between FBO and spatial cognition in heterosexual and homosexual males (Rahman, ; cf. Bogaert, ).
The current meta-analysis had several important limitations. Many of these are similar to those in our original meta-analysis so will not be repeated here. However, specific to the present analysis, we note that the heterogeneity between studies was high given the broad 95% confidence intervals. We have suggested that methodological variation (e.g., cognitive domain differences) is a significant contributor to this heterogeneity. Second, the number of studies for some cognitive domains included in the multivariate meta-analysis was small, which generally resulted in broad 95% confidence intervals (e.g., spatial location memory, female-favoring tasks, and male-favoring other tasks). Broad 95% confidence intervals indicate considerable uncertainty in effect sizes. Thus, more research with appropriate sample sizes is needed and this may change the conclusions. Finally, we were unable to find sufficient numbers of studies which reported within-group correlations between multiple cognitive tasks (only four studies reported the correlations). This latter point is of note for future research because having within-group correlations between tasks would permit the calculation of multivariate effect sizes (such as Mahalanobis D or other indices of multivariate distances). Such metrics would allow tests of the overall magnitude of sexual orientation differences where the groups differ along many variables of interest or where the construct is multidimensional (Del Giudice, ).