We identify weaknesses and inconsistencies in the Sperm Count Decline hypothesis; sperm count varies within a wide range, much of which can be considered non-pathological and species-typical

The future of sperm: a biovariability framework for understanding global sperm count trends. Marion Boulicault et al. Human Fertility, May 10 2021. https://doi.org/10.1080/14647273.2021.1917778

Abstract: The past 50 years have seen heated debate in the reproductive sciences about global trends in human sperm count. In 2017, Levine and colleagues published the largest and most methodologically rigorous meta-regression analysis to date and reported that average total sperm concentration among men from ‘Western’ countries has decreased by 59.3% since 1973, with no sign of halting. These results reverberated in the scientific community and in public discussions about men and masculinity in the modern world, in part because of scientists’ public-facing claims about the societal implications of the decline of male fertility. We find that existing research follows a set of implicit and explicit assumptions about how to measure and interpret sperm counts, which collectively form what we term the Sperm Count Decline hypothesis (SCD). Using the study by Levine and colleagues, we identify weaknesses and inconsistencies in the SCD, and propose an alternative framework to guide research on sperm count trends: the Sperm Count Biovariability hypothesis (SCB). SCB asserts that sperm count varies within a wide range, much of which can be considered non-pathological and species-typical. Knowledge about the relationship between individual and population sperm count and life-historical and ecological factors is critical to interpreting trends in average sperm counts and their relationships to health and fertility.

Keywords: Sperm count declinemale reproductive healthmale fertilitysemen analysisandrologyhuman reproduction

Contrasting the sperm count decline and sperm count biovariability hypotheses

In this paper we contrast the Sperm Count Decline and Sperm Count Biovariability hypotheses. We understand a hypothesis as not only a set of propositions open to empirical testing, but also as a set of implicit and explicit model-theoretic assumptions about the world that provides a framework for collecting and interpreting new and existing data and setting research agendas.

The SCD hypothesis interprets data on sperm count over time as a metric of men’s potential fertility, a proxy for men’s health, and an assay of environmental quality. According to SCD, a decline in ‘Western’ sperm counts from 1970s levels indicates a decline in male fertility, health, and a sign of a degrading environment. By contrast, the SCB hypothesis allows for the possibility of both pathological and non-pathological variation in sperm counts across populations and time. SCB begins with the premise that, above the threshold necessary for fertility, there is no basis to assume that high average population sperm counts are optimal. Nor is there any reason to believe that sperm counts in the 1970s are a species-typical baseline. SCB posits that sperm count varies within and across bodies in ways that are compatible with health such that a decline in an individual or population may not necessarily signal danger to fertility or well-being. We emphasise that while SCB invites a wider explanation and interpretation of sperm count trends, it does not exclude the possibility of sperm count decline or that decline may carry implications for men’s health and fertility. The SCB hypothesis provides a framework for exploring the trends identified by Levine et al. (2017) that considers the possibility that these trends can be explained by benign or adaptive variation in sperm counts in relation to diverse contexts and factors. Rather than treat nations or regions of global wealth as proxies for stable populations or biologically meaningful environments, SCB calls for testing links between specific developmental and proximate stimuli and sperm count outcomes, recognising human biological variation as local and situated (Lock, 2017; Niewohner & Lock, 2018).

From an SCB perspective, the data points that make up the 2017 meta-analysis simply demonstrate that sperm count varies across bodies, ecologies, and time periods. Examining the same data and background literature with a different set of assumptions, SCB argues that the interpretation that population sperm counts vary within a wide optimum with little consequence for fertility is at least as plausible as the interpretation that steady decline occurs.

We argue in favour of the SCB as a framework for interpreting population trends in human sperm counts. It identifies testable hypotheses that include both pathological and non-pathological explanations for and outcomes of observed variation in sperm counts. Table 2 contrasts the propositions of the SCD and SCB hypotheses. In the following sections, we analyse each proposition pair in turn.

1. Sperm count and men’s fertility

The SCD hypothesis contends that lower average population sperm counts portend higher rates of male infertility, positioning sperm count decline as a marker or cause of reproductive crisis for the human species. Levine et al. (2017) for example, infer that ‘declining mean [sperm count] implies that an increasing proportion of men have sperm counts below any given threshold for sub-fertility or infertility’. Levine et al. (2017) link this to claims of increasing ‘economic and societal burden of male infertility’ (p. 649).

There is little evidence that this is true. Levine et al. (2017) contend that the high circa 1973 numbers represent normal, healthy, and natural levels, while today's numbers represent a crisis and decline from a prior optimum. But current Western average sperm counts reported by Levine et al. (2017) for men unselected for fertility are well within the ‘normal’ range, defined by the World Health Organisation (WHO) as 15–259 million per mL for individuals (World Health Organization, 2010, p. 224). That is, the Levine et al. (2017) study reports a population average decline from ‘normal’ (99 million sperm per ml) to ‘normal’ (47 million sperm per ml). Furthermore, in absolute numbers, the 2009–2011 Unselected Western sperm counts (47.1 million/mL), which are ostensibly cause for alarm, are in fact relatively close to absolute sperm counts in ‘Other’ countries back in the 1978–1983 period (66.4 million/mL for Fertile Other, 72.7 million/mL for Unselected Other) and in the 2010–2011 period (75.7 million/mL for Fertile Other, 62.6 million/mL for Unselected Other).

Male infertility is a complex biological and social phenomenon that cannot be understood in terms of the single metric of sperm count (Guzick et al., 2001). Though azoospermia (sperm count of zero) guarantees infertility, researchers have found that some men with low sperm counts can conceive, while others with higher counts cannot (Patel et al., 2018; Wang & Swerdloff, 2014). Guzick et al. (2001) demonstrate that even sperm concentrations in the so-called sub-fertile range of less than 13.5 million/mL ‘do not exclude the possibility of normal fertility’ (p. 1392). Of note, the 2010 WHO reference values for semen parameters do not predict infertility, as the values were determined by studying fertile men; therefore, while the top 95% of sperm concentrations in the sample were taken to be the reference range, all of the men with sperm concentrations below the 5th centile were also fertile (Chiles & Schiegel, 2015; Cooper et al., 2010). Other studies from across the world have similarly confirmed the fertility of men below the WHO reference values (Haugen et al., 2006; Tang et al., 2015; Zedan et al., 2018).

Clinicians do not report proportionate increases in infertile men presenting for clinical consultation over Levine et al.’s study period (Inhorn & Patrizio, 2015). As urologist Peter Schlegel remarked in The New York Times in reference to the Levine et al. (2017) meta-analysis, ‘If you had a decrease in sperm count in the 50 to 60 percent range, we would expect the proportion of men with severe male infertility to be going up astronomically. And we don’t see that’ (Bowles, 2018). There is insufficient evidence to support claims of increasing rates of male subfertility in recent decades (Inhorn & Patrizio, 2015).

We note that there exists no species optimum in many other measures of reproductive function in men and women. As a concrete example, the gonadal steroid hormones testosterone, oestradiol, and progesterone are necessary to fertility (Dohle et al., 2003; Laufer et al., 1982; Welt et al., 2003). Researchers have documented significant variation in these hormones within and across populations and within individuals over time (Bjørnerem et al., 2006; Stanton et al., 2011; Vitzthum et al., 2004). As the WHO does with sperm count, researchers validate and publish non-pathological ranges for gonadal steroid hormones for use in clinical evaluation (Bhasin et al., 2011; Elmlinger et al., 2002). Within those ranges, higher levels are not considered absolute signals of better fertility or health (Bribiescas, 2016).

2. Sperm count as an assay of men’s health

SCD interprets sperm count decline as a biomarker of declining overall health status among men. Citing studies associating reduced sperm count and ‘increased all-cause mortality and morbidity’ (Levine et al., 2017, pp. 647, 649, 654), Levine et al. (2017) hypothesise that average population declines in sperm counts represent ‘a ‘canary in the coal mine’ for male health across the lifespan’ (p. 654; see also Skakkebaek et al., 2001). This metaphor suggests that low sperm counts are not only a barometer of men’s current health, but also a warning sign of future risks.

While there is evidence of a relationship between abnormal semen parameters and poor health status (Eisenberg et al., 2014), there is little evidence that average sperm count by itself is a valid summary measure of health status of men within a population. Recent work in a population in Córdoba, Argentina, suggests that, while semen parameters decline with age, lifestyle and health factors such as obesity, alcohol, and smoking have only modest associations with decline (Veron et al., 2018). Similar findings exist with respect to other semen parameters: a 1999 study of 939 UK men found no relation between sperm motility and common lifestyle factors such as consumption of alcohol, use of tobacco or recreational drugs, or high body mass index (Povey et al., 2012).

Specific relationships between sperm parameters and developmental and current conditions, including health status, remain to be established. Sperm variability can reflect endogenous and exogenous stimuli on both short and longer time scales. Spermatogenesis is a 42–76 day process (Misell et al., 2006). Interventions can occur at any point from the first division of the spermatogonia to the mature sperm’s journey through the epididymis (Chenoweth & Lorton, 2014). Research on livestock indicates that, depending on the developmental stage of their influence, effects can be permanent or may resolve. For example, enhanced nutrition in early life increased adult sperm production in bulls, but later-life nutrition could not compensate for early-life nutritional deficits (Kastelic, 2013). Seasonal climate variation, however, had only a transient effect on sperm parameters in bulls (Valeanu et al., 2015). Further research is needed to establish whether the same range of developmental and transient effects can be found in humans.

Prospective study models that use repeat individual measures in combination with a wide variety of social and biological measures are needed to identify potential confounders and causal variables in sperm biovariation. Such variables include transient exposures such as heat or tight clothing; the stimulus conditions under which the sample was collected, including available arousal material and duration of arousal pre-ejaculation; lifestyle factors including activity and diet; and developmental or environmental exposures like maternal smoking, pollutants, and endocrine disruptors (for examples of existing cross-sectional studies along these lines, see Gaskins et al., 2015; Inhorn et al., 2008; Priskorn et al., 2018). Without longitudinal individual and population data with sufficient ecological granularity, causal claims about the relationship between average population sperm counts and environments or lifestyles cannot be empirically substantiated.

In any case, the connection between sperm count and health is mediated by the individual’s recent experience and prior life history. For example, increased exercise does not have a stable relationship to sperm production, in part because the effect of exercise is mediated by current fitness level (Ibañez-Perez et al., 2019; Jóźków & Rossato, 2017; Rosety et al., 2017). Factors such as seasonal temperature and illness do not have uniform effects on the sperm production process for similar reasons. Given the range of relationships between stimulus and effect in spermatogenesis, sperm count is not an independent metric of human well-being.

3. Sperm count and environmental pollutants

In line with the TDS hypothesis (Bay et al., 2006; Skakkebaek, 2016), SCD asserts that the likely causes for sperm count declines among ‘Western’ populations are endocrine disruptors and other environmental pollutants introduced by industrialisation, as well as changes in men’s lifestyles. Levine et al. (2017) write that, ‘sperm count and other semen parameters have been plausibly associated with multiple environmental influences, including endocrine disrupting chemicals, pesticides, heat and lifestyle factors, including diet, stress, smoking and BMI’ (Levine et al., 2017, p. 649). In a Guardian article titled, ‘Sperm counts are on the decline - could plastics be to blame?,’ Levine identifies endocrine-disrupting chemicals (EDCs) such as plastics as a major cause of dropping sperm counts (Carr, 2019).

While environmental context undoubtedly affects men’s health, empirical research to date does not support a stable causal relationship between EDCs – exogenous chemicals that interfere with hormone action, typically through mimicking endogenous hormones and binding to protein receptors – and any indices of sperm health, including sperm count, sperm motility, and fertility (Bonde et al., 2016; Zamkowska et al., 2018). Scientists have approached questions about the impact of EDCs on reproductive function through animal models and human studies. In animal studies, male rodents are exposed to specific quantities of EDCs in a controlled environment, and systematically examined for effects on their reproductive health. In contrast, human clinical and epidemiological studies are primarily observational, studying the sperm of human males in the general population who were accidently exposed to unspecified levels of EDCs.

The strongest evidence for the impact of EDCs on human populations lies in their action as somatic carcinogens (Soto & Sonnenschein, 2010). Although reproductive cancers could plausibly lower sperm count, this pathway cannot explain the patterns reported by Levine et al. (2017) as they exclude cancer patients from their study. EDC exposure is also associated with risk for a wide range of health conditions outside of its effects on reproductive health, including non-reproductive cancers, diabetes, thyroid disorders, and neurological conditions (Gore et al., 2015). Some scientific research suggests that EDCs can have reproductive, neurological, and immunological effects on developing human foetuses (of both males and females), but more research is required to establish the exact relationship (Abaci et al., 2009; Bonde et al., 2016).

Even if EDCs cause a decline in sperm count, higher levels of industrial pollutant exposure in the West cannot explain the divergent trends in Levine et al.’s categories of ‘West’ versus ‘Other.’ Scientists have used the global distribution of plastics as a geological indicator of the extent of human altered landscapes (Zalasiewicz et al., 2016). It is widely established that the inequities of global capitalism disproportionately burden the global poor and indigenous peoples with the consequences of toxic pollution (Martinez-Alier et al., 2016). Substantial evidence suggests that pesticide poisoning is an equal or greater problem in low- and middle-income countries as in high-income countries (Jørs et al., 2018); the World Health Organization (2016) reports that 98 percent of people in urban low- and middle-income countries are exposed to unhealthy levels of toxic pollution.

The study period of 1973 to 2011 included in Levine et al. (2017) accompanied increasing global levels of industrial pollution (He et al., 2002; Karan & Bladen, 1976; Ramakrishnan, 2018). As a detailed example, consider two studies from Hyderabad, Andhra Pradesh, both included in Levine et al. (2017): one from a lead-acid battery manufacturing facility in Patancheru District and another at an anonymous lead welding facility (Danadevi et al., 2003; Vani et al., 2012). The 1970s initiated a rapid intensification of environmental pollution, in the form of waste disposal, air pollution, wastewater effluents, and occupational exposures in this region (Danadevi et al., 2003; Vani et al., 2012). Half of India’s rivers today are polluted by industrial wastewater effluents introduced in the 1970s; in Hyderabad, water sources were contaminated with industrial metals as early as 1983 (Karan & Bladen, 1976; Prahalad & Seenayya, 1988). Vegetables grown and consumed in urban Hyderabadi areas are packed with lead, cadmium and chromium, and bodies of water sampled are saturated with EDCs (Kiran Kumar et al., 2016; Ramakrishnan, 2018; Srikanth & Papi Reddy, 1991). In summary, evidence does not support the claim that increased exposure to environmental pollutants in the nations categorised by Levine et al. (2017) as ‘Western’ could be a plausible driver of distinctions between average population sperm count in ‘Western’ compared to ‘Other’ nations.

4. ‘West,’ ‘Other,’ and nations as units of population

Levine et al. (2017) extracted 244 estimates of average sperm counts from human sperm samples collected over the period 1973–2011 and reported in English-language publications, representing 42,935 individual men across the globe. They report that the average sperm concentration across Unselected ‘Western’ populations was 99 million/ml in 1973, declining to 47.1 million/ml in 2011, or 52.4% overall (Table 3). Sperm declines were only statistically significant in studies in ‘Western’ countries (Levine et al., 2017, p. 654), while ‘[n]o significant trends in SC [sperm concentration] or TSC [total sperm count] were seen in ‘Other’ countries overall, or for Unselected or Fertile men separately’ (Levine et al., 2017, p. 652).

Table 3. Sperm concentration in the first and last years of the Levine et al. (2017) meta-regression analysis, for all men and by fertility and geographic groups ‘Western’ and ‘Other.’

CSVDisplay Table

The study design of Levine et al. (2017) separated men along axes of fertility and geography. First, they categorised men as ‘Unselected,’ meaning that it was not known whether or not they had conceived a pregnancy, or as ‘Fertile,’ meaning that they had conceived a pregnancy. They next disaggregated men by the nation of the study in which they participated: Europe/Australia; North America; and ‘Other,’ which included South America, Asia, and Africa.

Constituting ‘Western’ and ‘Other’

Notably, the model used by Levine et al. (2017) generated statistically significant declines in sperm concentration over time for both Unselected and Fertile Europe/Australia cohorts, and for the Unselected North America Cohort, but not for the Fertile North America cohort (p = 0.29) or either of the Other cohorts (p = 0.30 for Unselected Other, 0.41 for Fertile Other) (Levine et al. (2017) Table S3). In the final published study, Levine et al. (2017) aggregated North American and Europe/Australia data to create a ‘Western’ cohort. Their justification was the similarity of effect magnitude in the data (despite one subgroup – Fertile North America – being statistically insignificant) and that North American data comprised only 16% of the estimates. In the final model, both Unselected and Fertile Western had statistically significant negative effects. In other words, sperm count declines in North America among Fertile men, which were not previously significant (p = 0.29), gained manufactured significance (p = 0.033) by being weighted with the European/Australian data in the final model.

It is justifiable to explore multiple aggregations of data along hypothesis-driven inquiries. However, the reframing of a statistically insignificant decline in fertility among Fertile North American men implies a level of certainty that the data do not support. When this certainty is adopted by public-facing reporting, it not only contributes to unfounded panic over ‘Western’ fertility, but also may influence the course of future research programs.

The data included in the meta-analysis are sparse by any measure. Global coverage is mottled and asymmetric. Levine et al. (2017) recognise that data on sperm count in ‘Other’ countries is much sparser than in ‘Western’ countries, as illustrated by Figure 1 and Table 3. Less evident yet still important is the quantitative and qualitative variation in the data points at the level of the nation and the region. For example, the preponderance of sperm count studies over a range of time periods from several major Danish cities included in the meta-analysis might allow researchers to describe general population trends in sperm count within Denmark. However, the same number of studies, or fewer, conducted at disparate times in such large and heterogeneous countries such as India or China cannot hope to capture the same granularity of data by averaging sperm counts.

Figure 1. Number of sperm samples per country over the period 1973–2011 included in the 2017 meta-analysis.

Display full size

Studies of men unselected by fertility (i.e. men assumed to be representative of the general population in a given geographic area) included in the meta-analysis vary in study design and sample composition across geographic location. For example, control groups in studies of the impact of an environmental exposure on sperm quality were extracted for inclusion in Levine et al. (2017). Studies conducted in this way contribute more samples to some national data pools than others. For example, of 10 separate studies conducted in Denmark, four (40%) were interested in the impact of a specific exposure (e.g. pesticides or maternal folic acid) on sperm quality. By contrast, 13 of the 16 studies in the United States (81%) are exposure studies, looking at the effects of a chemical exposure, smoking, stress, or a medical condition such as cryptorchidism on sperm quality. And 100% of the five studies used for Unselected samples in all of Central and South America were designed to study sperm quality in the context of a specific exposure, whether pesticides, contaminants, or a medical condition. This is important because the controls in these exposure studies are often convenience samples relative to study subjects. For example, a study in Mexico City on rubber factory workers exposed to hydrocarbons used a control group consisting of employees working in the factory’s administrative offices (De Celis et al., 2000), and a study in San Francisco on sperm quality in anaesthesiologists had anaesthesia residents serve as controls (Wyrobek et al., 1981). As Fleiss and Gross (1991) explain, factors other than exposure may affect whether a sample is a case or a control, and these confounding variables can obscure the associations of interest.

Interpreting average sperm count in a nation

The SCD treats nations and continents as bounded populations, with men unselected by fertility described as ‘more likely to be representative of the general population’ in that nation or continent (Levine et al., (2017), p. 655). That is, continents or nations are conceptualised as population samples that can be used to compare, for example, average 1973 sperm counts to average 2011 sperm counts.

Within this paradigm, the categories ‘West’ and ‘Other’ rely on a particular vision of a static national population that obfuscates the role of several types of migration in continually redefining how these populations are constructed. Since the 1970s, repeated, large-scale, highly varied movements of populations have occurred across national borders, and in particular between nations categorised by Levine et al. (2017) as ‘Other’ to ‘Western’ countries. Yet these movements, from East and South to North and West, from rural to urban, and across many kinds of differently polluted and polluting ecologies, are lost entirely in the racial/national geopolitical categories of difference uncritically embraced by current instantiations of the SCD hypothesis. If biological variables such as sperm count are to be understood as ecologically dependent at the population level, patterns of migration since the 1970s that have fundamentally reshaped nations categorised as ‘West’ and ‘Other’ must be taken into consideration.

During the time period covered by the Levine et al. (2017) meta-analysis, patterns of migration have redistributed formerly concentrated populations into a contingent of increasingly heterogeneous cities and states, predominantly in the Global North and West. In Western Europe, decolonisation as well as the proliferation of guest worker programmes to meet the needs of a broadly booming post-war economy brought individuals from former colonies distributed over three continents, combined with workers from North Africa and Southern Europe, into Northern and Western Europe (Moch, 2003; Van Mol & de Valk, 2016). Sweden, for instance, which historically had higher emigration than immigration, saw a rapid population change after World War II. Immigration rates peaked in 2013. As a result, 24% of the population is now foreign-born, and its ethnic composition has also shifted. Migration from Africa again rose in the 1990s and migration from across Asia and Latin America into Western Europe rose significantly from the turn of the 21st century (Pellegrino, 2004; Van Mol & de Valk, 2016). Meanwhile in North America, the United States has also seen significant demographic shifts precipitated by evolving migration patterns. Due to alterations to US migration law after 1965, most immigrants after 1970 were of Latin American or Asian origin, whereas previously they had been predominantly of European origin. Simultaneously, total immigration in the US increased dramatically – from approximately 5% to nearly 15% of the total population (Martin, 2014).

Within the nations broadly categorised by Levine et al. (2017) as ‘Other,’ which comprise the large majority of the world by aggregate population, migration has also played a formative role in shaping demographic distribution since the 1970s. Large-scale internal migration in large and populous nations such as China and India, predominantly from rural to urban settings, was generated by rapid industrialisation and entry into global markets by many states in the 1970s that created the need for more robust industrial workforces (Liang & Ma, 2004; Lusome & Bhagat, 2006). In the same states during the same period, international migration played a similarly important role in structuring demographics; the Opening of China in the later-1980s saw a renewed wave of emigration of diverse individuals, and the oil boom in the Gulf States in the 1970s saw the efflux of labourers from India and into new ‘Other’ nations (Ecevit, 1981; Ganeshan, 2011; Khadria, 2006; Xiang, 2016). In summary, particularly if the SCD assumes that the influence of interest is the individual’s developmental rather than current environment, country of residence is a poor proxy for a sample population, because populations have not stayed within their borders during the study period.

Attending to the globalising processes of migration, development, and pollution reveals that the differences assumed between so-called ‘West’ and ‘Other’ countries do not apply to the study period covered in Levine et al. (2017). South India can act as an exemplar of a region that has undergone momentous shifts in ecology and demography since the 1970s, brought about by ongoing internal and international migration and environmental pollution from globalising industrialism. The 1970s Gulf oil boom contributed to an increase in Indian emigration (particularly among males), as did India’s growing global economic presence, which led to a ‘brain drain’ migration among educated and skilled Indians to the global West (Chacko, 2007; Ganeshan, 2011). Now, across India, rural-to-urban migrants account for more than half of the population of cities (Ganeshan, 2011; Irudaya Rajan & Sumeetha 2020). Hyderabad too has seen decades of cyclical immigration from rural areas towards urban industrialisation, emigration abroad both to ‘West’ and ‘Other’ nations, and a recent reversal of this process wherein Western-trained Indians return as Hyderabad grows in its transnational, globally connected contemporary networks (Chacko, 2007). The social and environmental experience of growing up and living in South India in the 1970s, for example, is not comparable to that of South India in the 2010s. It is unclear how Levine et al. (2017) locate ‘India’ in their analysis, whether as a place with a set of defined ecological conditions, as a group of people, or as a place that might have changed over time ecologically but where the population has remained constant enough to allow for disambiguation of the effects of place on sperm production from any other effects. We suggest that it is not obvious that the genetic composition of a population in a given place remains the same over time. Nor is it certain that the people in a given place have experienced the developmental environment of that place, or that the place has remained ecologically stable (or not) in predictable or documented ways.

A biovariability framework emphasises that the appropriate unit of analysis to understand relationships between ecology and average population sperm count is a spatiotemporally continuous population, in which bio-environmental and socio-cultural exposures and their outcomes can be tracked over time within and among individuals at multiple time points. Levine et al. (2017) assume that geographic regions such as nations and continents over the period from 1973 to the present day represent such populations. Although it may sometimes be the case that geopolitical boundaries can meet these criteria, the highly dynamic history of migration and environmental change since 1973, wrought by increasingly globalised processes, indicates that the nation-level sperm count averages utilised by Levine et al. (2017) are inappropriate categories for understanding sperm count epidemiology.

COVID... Very different patterns across higher- & lower-income migrants: Higher income households moving out of more populous cities at greater rates, and moving more for lifestyle reasons and much less for work-related reasons

Haslag, Peter H. and Weagley, Daniel, From L.A. to Boise: How Migration Has Changed During the COVID-19 Pandemic (March 26, 2021). SSRN: http://dx.doi.org/10.2139/ssrn.3808326

Abstract: We provide an initial assessment of how migration patterns and migrants motivations for moving have changed during the COVID-19 pandemic. We use proprietary data on over 300,000 residential, interstate moves over the last four years, which includes details on each move as well as detailed survey data. We find 10--20% of moves between April 2020--February 2021 were influenced by COVID-19, with a significant shift in migration towards smaller cities, lower cost of living locations, and locations with fewer pandemic-related restrictions. We find very different patterns across higher-income and lower-income migrants with higher income households moving out of more populous cities at greater rates, and moving more for lifestyle reasons and much less for work-related reasons compared to the pre-pandemic period. Our results have implications for the structure of cities, tax and political bases, real estate, and other outcomes of interest.

Keywords: COVID-19, Pandemic, Relocation, Remote Work, Agglomeration

JEL Classification: R23, J61, J11, R10, O15

The dark triad consists of psychopathy, machiavellianism, and narcissism; the dark triad is mostly negatively related to emotional intelligence; only narcissism is positively related to trait EI

Emotional intelligence and the dark triad: A meta-analysis. Moritz Michels, Ralf Schulze. Personality and Individual Differences, Volume 180, October 2021, 110961. https://doi.org/10.1016/j.paid.2021.110961

Highlights

• The dark triad consists of psychopathy, machiavellianism, and narcissism.

• A meta-analysis regarding emotional intelligence and the dark triad was conducted.

• The dark triad is mostly negatively related to emotional intelligence.

• The relations are small and similar for trait EI and ability EI.

• Only narcissism is positively related to trait EI.

Abstract: The dark triad is commonly conceived of three subclinical socially aversive and exploitative personality traits: psychopathy, machiavellianism, and narcissism. These traits have been linked to certain abilities that may facilitate the attainment of goals in social interactions, one of which may be emotional intelligence. Emotional intelligence encompasses the abilities to perceive emotions correctly, to understand the regularities of emotional functioning, and to regulate one's own and others' emotions. However, it has alternatively also been conceptualized as a set of emotion-related personality characteristics assessed with self-reports (Trait emotional intelligence). The aim of this study was to examine the possible relationships between the dark triad and emotional intelligence. A meta-analysis with a total of 109 effect sizes (6 ≤ ks ≤ 30) culled from 71 studies was conducted. Of the resulting six most relevant combined effect sizes (1561 ≤ Ns ≤ 8127), five were small and negative (−.23 ≤ s ≤ −.13). Only the correlation between narcissism and emotion-related personality characteristics was small and positive ( = .15). In total, the results indicate that the dark triad constructs are only weakly related to emotion-related traits, either conceptualized as abilities or personality characteristics.

Check also Neither the dark triad nor general intelligence are meaningfully related to lying ability:

The ability to lie and its relations to the dark triad and general intelligence. Moritz Michels, Günter Molz, Frederic Maas. Personality and Individual Differences, Volume 166, 1 November 2020, 110195. https://www.bipartisanalliance.com/2020/07/neither-dark-triad-nor-general.html

More women (45.8%) than men (21.6%) report that they wished they had waited until an older age to have sex; fewer women (1.5%) than men (13.9%) wished that it had occurred sooner; no differences in actual age of sexual debut

Perhaps It Was Too Soon: College Students’ Reflections on the Timing of Their Sexual Debut. Susan Sprecher et al. The Journal of Sex Research , Mar 1 2021. https://doi.org/10.1080/00224499.2021.1885599

Abstract: Early sexual debut has been a focus of social scientific research due to its association with adverse circumstances and negative outcomes. However, there has been a recent shift to considering not only chronological age, but also the degree to which the event is viewed to be optimally timed (i.e., the perception that it occurred at the “right time” versus too soon). The purpose of this study was to assess how individual/family background variables and contextual aspects of the experience (including partner and relationship aspects) are associated with both the actual age at sexual debut and the perceived acceptability of the timing of the event. Using data collected from students at a U.S. university between 1990 and 2019 (N = 6,430), several factors (in addition to chronological age) were associated with the perceived acceptability of the timing of sexual debut. Strong gender differences were found – women perceived their timing to be less acceptable, even though they did not differ from men in actual age at sexual debut. Other robust predictors of perceived acceptability included (lower) religious involvement and recalling desire (for the experience), pleasure, and lower guilt at the time. Only slight changes occurred over the 30-year period in age at sexual debut and perceived acceptability of the timing. Suggestions for future research are provided and implications for sex education/sexual health interventions are discussed.

Attractive‐disadvantageous partners were preferred to the same extent (or more) as unattractive‐advantageous partners; the effect of attractiveness was fully explained by the perceived trustworthiness of the financial partners

What is a face worth? Facial attractiveness biases experience‐based monetary decision‐making. Gayathri Pandey  Vivian Zayas. British Journal of Psychology, May 9 2021. https://doi.org/10.1111/bjop.12495

Abstract: There is ample evidence that attractive individuals, across diverse domains, are judged more favourably. But most research has focused on single/one‐shot decisions, where decision‐makers receive no feedback following their decisions, and outcomes of their judgements are inconsequential to the self. Would attractive individuals still be judged favourably in experience‐based decision‐making where people make iterative decisions and receive consequential feedback (money gained/lost) following each decision? To investigate this question, participants viewed headshots of four financial partners presented side‐by‐side and repeatedly (over 50–100 trials) selected partners that would help maximize their profits. Following every partner‐selection, participants received feedback about the net monetary gains/losses the partner had conferred. Unbeknownst to participants, two partners (one attractive, one unattractive) were equally advantageous (conferred net‐gains overtime) and two partners (one attractive and one unattractive) were equally disadvantageous (conferred net‐losses overtime). Even though attractive and unattractive partners were equally profitable and despite receiving feedback, participants selected attractive partners more throughout the task were quicker to reselect them even when they conferred losses and judged them as more helpful. Indeed, attractive‐disadvantageous partners were preferred to the same extent (or more) as unattractive‐advantageous partners. Importantly, the effect of attractiveness on decision‐making was fully explained by the perceived trustworthiness of the financial partners.

Scratch-cards are less strongly associated with problem gambling, since it is less continuous than slot machines, has a slower event frequency, & near-miss design features are unlikely to have a significant impact upon behaviour

Empirical Evidence Relating to the Relative Riskiness of Scratch-Card Gambling. Paul Delfabbro & Jonathan Parke. Journal of Gambling Studies, May 10 2021. https://rd.springer.com/article/10.1007/s10899-021-10033-2

Abstract: Scratch cards (SCs) or tickets are lottery-based games which are played by scratching to reveal numbers, letters or symbols to win prizes. Such activities have sometimes been likened to paper-based slot-machines, but relatively little systematic analyses have been conducted to examine the risk or harm associated with these activities. In this paper, we provide a narrative review of the peer-reviewed literature relating to the potential association between SCs and problem gambling and what is known from publically available data sources (e.g., prevalence studies and treatment data). Evidence is analysed within the context of the Bradford Hill Criteria. Both prevalence and peer reviewed literature suggest that SCs are less strongly associated with problem gambling than most other gambling activities. We argue that this difference is due to the nature of the products. SC gambling differs from slot-machine gambling in a number of structural ways; it is less continuous; has a slower event frequency; and, emerging literature suggests that near-miss design features are unlikely to have a significant impact upon behaviour. Thus, in our view, and based on the empirical evidence, it appears that earlier parallels between SCs and slot-machines now appear more tenuous. Nevertheless, we encourage further investigation into the potential impact of new and emerging online lottery products because of the more immersive, faster and more technology-based nature of these products.

Moving toward a single‐payer system will reduce billing and insurance‐related costs, but certain reforms to contracts could generate at least as many cost savings without radically reforming the health system

Reducing administrative costs in US health care: Assessing single payer and its alternatives. David Scheinker  Barak D. Richman  Arnold Milstein  Kevin A. Schulman. Health Services Research, March 31 2021. https://doi.org/10.1111/1475-6773.13649

Abstract

Objective: Excess administrative costs in the US health care system are routinely referenced as a justification for comprehensive reform. While there is agreement that these costs are too high, there is little understanding of what generates administrative costs and what policy options might mitigate them.

Data Sources: Literature review and national utilization and expenditure data.

Study Design: We developed a simulation model of physician billing and insurance‐related (BIR) costs to estimate how certain policy reforms would generate savings. Our model is based on structural elements of the payment process in the United States and considers each provider's number of health plan contracts, the number of features in each health plan, the clinical and nonclinical processes required to submit a bill for payment, and the compliance costs associated with medical billing.

Data Extraction: For several types of visits, we estimated fixed and variable costs of the billing process. We used the model to estimate the BIR costs at a national level under a variety of policy scenarios, including variations of a single payer “Medicare‐for‐All” model that extends fee‐for‐service Medicare to the entire population and policy efforts to reduce administrative costs in a multi‐payer model. We conducted sensitivity analyses of a wide variety of model parameters.

Principal Findings: Our model estimates that national BIR costs are reduced between 33% and 53% in Medicare‐for‐All style single‐payer models and between 27% and 63% in various multi‐payer models. Under a wide range of assumptions and sensitivity analyses, standardizing contracts generates larger savings with less variance than savings from single‐payer strategies.

Conclusion: Although moving toward a single‐payer system will reduce BIR costs, certain reforms to payer‐provider contracts could generate at least as many administrative cost savings without radically reforming the entire health system. BIR costs can be meaningfully reduced without abandoning a multi‐payer system.

People in disaster situations tend to adhere to their social expectations; some groups have cohesive subsets of members who can split off from each other during evacuation without violating their group’s internal expectations

Network Structure in Small Groups and Survival in Disasters. Benjamin Cornwell, Jing-Mao Ho. Social Forces, soab036, April 29 2021. https://doi.org/10.1093/sf/soab036

Abstract: People in disaster and emergency situations (e.g., building fires) tend to adhere to the social obligations and expectations that are embedded in their preexisting roles and relationships. Accordingly, people survive or perish in groups—specifically, alongside those to whom they were connected before the situation emerged. This article uses social network analysis to expand on this collective behavior account. Specifically, we consider structural heterogeneity with respect to the internal configurations of social ties that compose small groups facing these situations together. Some groups are composed of cohesive subsets of members who can split off from each other during evacuation without violating their group’s internal role-based expectations. We argue that groups that possess this “breakaway” structure can respond to emergencies more flexibly. We explore this using data from the Beverly Hills Supper Club fire of 1977, which killed 165 people. Our data include 303 groups (“parties”) that consisted of 746 people who were present in the dining room where most of the fatalities occurred. Fatality rates were significantly lower in groups that were internally structured such that they could split up in different ways during the escape while still maintaining their strongest social bonds.

The end of Hale magnetic cycles affect the Sun's radiative output and particulate shielding of our atmosphere through the rapid global reconfiguration of solar magnetism, which makes El Nino switch to La Nina and back

Termination of Solar Cycles and Correlated Tropospheric Variability. Robert J. Leamon  Scott W. McIntosh  Daniel R. Marsh. Earth and Space Science, February 24 2021. https://doi.org/10.1029/2020EA001223

Abstract: The Sun provides the energy required to sustain life on Earth and drive our planet's atmospheric circulation. However, establishing a solid physical connection between solar and tropospheric variability has posed a considerable challenge. The canon of solar variability is derived from the 400 years of observations that demonstrates the waxing and waning number of sunspots over an 11(‐ish) year period. Recent research has demonstrated the significance of the underlying 22 years magnetic polarity cycle in establishing the shorter sunspot cycle. Integral to the manifestation of the latter is the spatiotemporal overlapping and migration of oppositely polarized magnetic bands. We demonstrate the impact of “terminators”—the end of Hale magnetic cycles—on the Sun's radiative output and particulate shielding of our atmosphere through the rapid global reconfiguration of solar magnetism. Using direct observation and proxies of solar activity going back some six decades we can, with high statistical significance, demonstrate a correlation between the occurrence of terminators and the largest swings of Earth's oceanic indices: the transition from El Niño to La Niña states of the central Pacific. This empirical relationship is a potential source of increased predictive skill for the understanding of El Niño climate variations, a high‐stakes societal imperative given that El Niño impacts lives, property, and economic activity around the globe. A forecast of the Sun's global behavior places the next solar cycle termination in mid‐2020; should a major oceanic swing follow, then the challenge becomes: when does correlation become causation and how does the process work?

3 Discussion

In the previous section, we have made use of a modified Superposed Epoch Analysis (mSEA) to investigate the relationships between solar activity measures and variability in a standard measure of the variability in the Earth's largest ocean—the Pacific. We have observed that this mSEA method brackets solar activity and correspondingly systematic transitions from warm‐to‐cool Pacific conditions around abrupt changes in solar activity we have labeled termination points. These termination points mark the transition from one solar activity (sunspot) cycle to the next following the cancellation or annihilation of the previous cycle's magnetic flux at the solar equator—the end of Hale magnetic cycles.

Correlation does not imply causation; however, the recurrent nature of the ONI signal in the terminator fiducial would appear to indicate a strong physical connection between the two systems. Appendix B discusses three statistical Monte Carlo tests that show the chances of these events lining up for five cycles are remote: in summary we may reject the null hypothesis of random cooccurrences with a confidence level p < 3.4 × 10−3. We do not present an exhaustive set of solar activity proxies, but it would appear that the CRF, as the measure displaying the highest variability, as something to be explored in greater detail in coupled climate system models.

There have been many possible explanations postulated for a cosmic‐ray climate connection, including: (i) Forbush decreases inducing increased extratropical storm vorticity (Roberts & Olson, 1973; Tinsley et al., 1989) and atmospheric gravity waves propagating from the auroral ionosphere (Prikryl et al., 2009); (ii) global electric conductivity inducing changes in cloud microphysics (Harrison, 2004; Tinsley, 2000); and (iii) direct formation of ionization particles seeding cloud formation (Svensmark & Friis‐Christensen, 1997; Svensmark et al., 2017). However, the effects of cosmic rays on cloud formation are a matter of hot debate (e.g., Gray et al., 2010; Kristjánsson et al., 2002; Pierce, 2017), with even the sign of the correlation between cosmic rays and climate not agreed on. For all the debate these explanations have generated, they are all irrelevant in terms of the correlations and empirical predictions we discuss here.

Independent of the exact mechanisms of coupling solar modulation to ENSO, which are beyond the scope of this manuscript, the results discussed above and shown in Figure 5 hold for the past five solar cycles, or 60 or so years. The question must be asked, then, why has the regular pattern of Figure 5 occurred and reoccurred regularly since 1966?

As Figure 4 shows, we only have continuous cosmic‐ray observations from 1964, just before the cycle 19 terminator. The F10.7 record extends back to 1947 (near the peak of cycle 17), but Pacific Sea Surface temperatures and sunspot areas extend to the 1870s. Other than the 1915 termination of solar cycle 14, there is little evidence for such a correlation prior to the events discussed here. (Cycle 14 was notably the weakest cycle of the twentieth Century, and thus almost certainly had the highest CRF prior to the continuous observation record.) However, there certainly have been changes in the Earth's atmosphere over the twentieth Century…

3.1 Atmospheric Changes

It is probably not a coincidence that the period of terminator‐ENSO correlation corresponds to the close‐to‐monotonic rise in global sea surface temperatures over the same time period as Figure 4 (the “hockey stick” graph). Tropospheric warming leads to stratospheric cooling (Ramaswamy et al., 2006); do the effects of a colder stratosphere on the physical and chemical processes in it make it more susceptible to amplifying transient changes in solar input? Further, since about 1945, the Pacific Decadal Oscillation (Mantua et al., 1997) has been in a predominantly negative phase, the feedback to net irradiance from clouds has been increasingly negative (Zhou et al., 2016), and a ∼4%–6% decrease in cloud cover over the western Pacific (∼140–160°E) has been reported from ship‐borne observations since 1954, with a comparable increase over the mid‐Pacific (∼150–120°W; Bellomo et al., 2014). Note that 160°E is the “balance point” about which warm and cold SSTs flip in an El Niño‐La Niña transition (Pinker et al., 2017).

Thus, over the past several decades the cloud pattern in the western Pacific has adopted an almost El Niño‐like default state, consistent with an observed eastward shift in precipitation in the tropical Pacific and weakening of the Walker circulation over the last century (Deser et al., 2004; Vecchi & Soden, 2007a), and which has been tied, via simple thermodynamics, to a warmer atmosphere. Over the same past four decades timeframe, evidence for a changing Brewer‐Dobson circulation—the mass exchange between troposphere and stratosphere characterized by persistent upwelling of air in the tropics—comes from satellite and radiosonde data, which indicate a reduction in temperatures and ozone and water vapor concentrations, particularly in the tropical lower stratosphere at all longitudes (Thompson & Solomon, 2005), pointing to an accelerated tropical upwelling (Rosenlof & Reid, 2008). Domeisen et al. (2019) discuss the teleconnection of ENSO both vertically, to the stratosphere, and thence latitudinally affecting the strength and variability of the stratospheric polar vortex in the high latitudes of both hemispheres: El Niño events are associated warming and weakening of the polar vortex in the polar stratosphere of both hemispheres, while a cooling can be observed in the tropical lower stratosphere. These impacts are linked by a strengthened Brewer‐Dobson circulation, with planetary waves generated by latent heat release from tropical thunderstorms being the likely modulation mechanism (Deckert & Dameris, 2008; Domeisen et al., 2019).

Thus, it is entirely plausible that since changes in the (upper) atmosphere brought on by a strengthened Brewer‐Dobson circulation, weakened Pacific Walker circulation, and less cloudy Western Pacific, enables the relatively constant terminator‐driven changes to have sufficient “impact” to flip the system from El Niño to La Niña, independent of the actual mechanism that couples solar changes to clouds and ENSO. Such circulation changes are only likely to intensify in a future with higher tropical heat and moisture at the sea surface, affecting not only tropospheric climate but also stratospheric dynamics.

3.2 Socioeconomic Implications

Forecasting ENSO and its related climate variations is a high‐stakes societal imperative given that El Niño impacts “lives, property, and economic activity around the globe” (McPhaden, 2015). For instance, as an example of not necessarily being concerned about why or how an empirical relationship works from a forecast standpoint, Smith et al. (2016) noted “An ability to forecast the time‐averaged NAO months to years ahead would be of great societal benefit, but current operational seasonal forecasts show little skill.” Dunstone et al. (2016) thus improved the skill of 12 months ahead NAO forecasts when an 11 years (solar cycle) parameterized solar irradiance forcing term was added. Smith et al. and Dunstone et al. focused on the severity of the British winter, primarily from the viewpoint of the energy and insurance sectors.

Directly focused on catastrophic ENSO impacts, flooding in Australia during the 2010–2012 La Niñas and the ensuing economic cleanup costs (A$5–10 billion (US$4.9–9.8 billion) in Queensland alone) led to the commissioning of a Government Report on “two of the most significant events in Australia's recorded meteorological history” (Bureau of Meteorology, 2012). Similarly, the Peruvian government estimated the very strong 1997–1998 El Niño event cost about US$3.5 billion, or about 5% of their gross domestic product (GDP). Globally, United Nations estimates of El Niño‐related damage from the same event ranged from US$32 to US$96 billion. In the United States, NOAA assessed direct economic losses from that event likely exceeded US$10 billion (Weiher, 1999).

The mild winters and greater than average rainfall to the Southwest in El Niño years save US energy consumers US$2.2 billion less in fuel heating costs (Teisberg, 1999); however, the savings is lost in La Niña years with more sever winters. Agriculture is the most climate sensitive industry and climate is the primary determinant of agricultural productivity. Estimates of the impacts on U.S. agriculture of the 1997–1998 El Niño and the 1998–1999 La Niña; those losses range from US$1.5–$1.7 billion from El Niño and US$2.2–$6.5 billion from La Niña (Chen et al., 2001; Weiher & Kite‐Powell, 1999). That assessment comes with the important caveat that losses associated with El Niño‐related floods or droughts in some areas can be offset by gains elsewhere, for instance through reduced North Atlantic hurricane activity, lower winter heating bills or better harvests for certain crops—Argentinian wheat yields are strongly increased in El Niño years, for example, whereas US (and moreso Canadian) yields fall (Gutierrez, 2017). Nevertheless, combining the costs of natural disaster recovery with the costs associated with yields of major commodity crops (Gutierrez, 2017; Iizumi et al., 2014), the need to be able to predict ENSO events beyond a seasonal forecast (e.g., https://community.wmo.int/activity‐areas/climate/wmo‐el‐ninola‐nina‐updates (World Meteorological Organization) is high.

That crop yields in North and South America, Australia, and Eurasia vary, along with regional temperature and precipitation changes, makes it clear that ENSO influences, through “teleconnections,” (e.g., Bjerknes, 1969; Domeisen et al., 2019) the global dynamics of seasonal winds, rainfall, and temperature. These teleconnections imply, indeed require, coupling throughout the atmosphere, and despite the mention of troposphere in the title of this paper, manifestations of ENSO are observed throughout the neutral atmosphere and higher.

One final economic impact consideration, also tied to global teleconnections, is the strength of Atlantic hurricane season, which is relatively strong in the first year of La Niña after an El Niño, when waters are still warm but upper‐level wind shears are favorable for cyclone genesis (Vecchi & Soden, 2007b). As such, we may expect a particularly active season in 2021, and maybe even 2020, depending on exactly when the terminator and ENSO transition occurs.

4 Conclusion

As discussed in M2014, the band‐o‐gram developed therein could be extrapolated linearly out in time. The linear extrapolation of the solar activity bands outward in time was verified in McIntosh et al. (2017) by updating the original observational analysis and comparing to the earlier band‐o‐gram. M2014 projected that sunspot cycle 25 spots would start to appear in 2019 and swell in number following the terminator in mid‐2020. Six years later, we are seeing these predictions come true with the first numbered active regions and low level (C‐class) flaring activity. Based on the mSEA of the past 60 years, an enduring warm pool in the central and western Pacific at solar minimum (ONI has been consistently positive since early 2018, even though it never got so warm to become a fully fledged strong El Niño event) was not unexpected, and we expect a rapid transition into La Niña conditions later in 2020 following the sunspot cycle 24 terminator. Given the warm waters, we project a particularly active Atlantic hurricane season in 2021, and maybe even 2020, depending on exactly when the terminator and ENSO transition occurs this year.

In conclusion, we have presented clear evidence in Figure 5 of a recurring empirical relationship between ENSO and the end of solar cycles. We have tried to avoid discussion of causation, which, due to its controversial nature could lead to dismissal of the empirical relationship, and we want open a broader scientific discussion of solar coupling to the Earth and its environment. Nevertheless, independent of the exact coupling mechanisms, the question must be asked, why has the pattern occurred and reoccurred regularly for the past five solar cycles, or 60 years? We have only a few months at most to wait to see if this Terminator‐ENSO relation continues at the onset of the coming solar cycle 25. Should this next terminator be associated with a swing to La Niña then we must seriously consider the capability of coupled global terrestrial modeling efforts to capture “step‐function” events, and assess how complex the Sun‐Earth connection is, with particular attention to the relationship between incoming cosmic rays and clouds and precipitation over our oceans. ENSO is the largest mode of atmospheric variability driving extreme weather events with large costs and so any improvement in prediction of that would be of societal benefit. 

Men are less likely than women to do listening during troubles talk

Santoro, Erik, and Hazel Markus. 2021. “How Do You Listen?: The Relationship Between How Men Listen and Women’s Power and Respect in the U.S.” PsyArXiv. May 10. doi:10.31234/osf.io/4ycf7

Abstract: As American culture confronts the issues raised by #MeToo, some ask, what can men do in interpersonal interactions to become allies and empower women? Building on research in linguistics, communication, sociology, as well as psychology, seven pre-registered studies investigate the relationship between how men listen during troubles talk (i.e., communication about problems) and women’s sense of power and respect. We theorize and compare two styles of effective listening: more other-focused interdependent listening (e.g., asking a question) and more self-focused independent listening (e.g., giving advice). We find that though men are less likely than women to do interdependent listening during troubles talk (Study 1), men can be encouraged to ask questions (Study 2). When investigating the effect on women of how men listen, we found that women anticipate feeling more powerful and respected when listened to by a man friend doing interdependent (vs. independent) listening (Studies 3a – 3c), particularly those women who do not endorse stereotypic gender roles (Study 3c). We partially replicated these findings in two live interaction studies involving strangers communicating over text: women felt more powerful and respected when listened to by men who asked open-ended questions compared to men who gave prescriptive, unsolicited advice (Study 5), though they did not when men simply asked more questions (Study 4). We suggest that listening can assume multiple productive forms, but that compared to independent listening, interdependent listening can serve as an everyday anti-sexist practice to attenuate rather than accentuate the gender hierarchy.