Saturday, January 4, 2020

Low-probability events were viewed as more random than similar events that were judged (rightly or wrongly) to be more likely; only extremely deviant outcomes made some people reject the randomness account

Are random events perceived as rare? On the relationship between perceived randomness and outcome probability. Karl Halvor Teigen & Gideon Keren. Memory & Cognition, January 2020.

Abstract: Many daily life events, from lotteries to coincidental encounters, occur partly or entirely randomly or “by chance.” Six experiments, in two different languages, explored how perceptions of randomness are related to the perceived probability of the same events—specifically, whether low-probability events were viewed as more random than similar events that were judged (rightly or wrongly) to be more likely. The experiments suggest that low-probability outcomes of stochastic events are indeed considered as being more random than medium and highly likely outcomes, even when all are produced by a “blind” (hence random) process. Degree of randomness involved in catching a bus was inversely related to the subjective probability estimates of the same event, both for correct and incorrect estimates. Unlikely coincidences were perceived to be more random than the same events presented in a more likely frame. The outcome of a match between two soccer teams was  deemed to be more random when the weaker team wins than when the stronger team wins. Only extremely deviant outcomes—for instance, a top student who fails on two successive exams—made some people reject the randomness account, presumably believing that such extreme events must have a causal explanation. We conclude that people generally associate randomness with low-probability events, indicating outcomes that “cannot be predicted.”

Check also Are random events expected to be small? Karl Halvor Teigen, Alf Børre Kanten. Psychological Research, September 30 2019.

General discussion

The present set of studies constitutes the first attempt to examine empirically how perceived randomness of singular events
is related to their judged probability. We reviewed arguments
for different, seemingly plausible accounts for such a relationship, but subsequent experiments offered most consistent support for the low-probability account: Low-probability events
will be perceived as more random than comparable outcomes
that are estimated (rightly or wrongly) to have a higher probability of occurrence. This supports the more informal observations by Shanahan and Porfeli (2006) and Jolfaee et al. (2014),
and is congruent with the fact that real-life stories about random happenings, particularly coincidences, are typically illustrated by descriptions of low-probability events (Bandura,
1982; Johansen & Osman, 2015).
The results of the first four experiments all supported the
low-probability hypothesis rather than a process account, endorsed by scientists who think that randomness “objectively”
depends upon the generating mechanism (Fitelson &
Osherson, 2015; Lecoutre et al., 2006; Nickerson, 2002).
Experiment 5, which compared probability estimates and perceived randomness of selected soccer results, indicated a potential boundary condition for this rule. Results that were considered highly likely were again perceived as being less random than those that were not considered so likely, whereas
exceptionally extreme unlikely results turned out to be ambiguous, as participants were split into those who thought that
such results indicated a very high degree of randomness and
those who thought that such results could not be due to
chance. This split was replicated in Experiment 6, where very
deviant exam grades were viewed as being either more random (because they were unusual) or less random (because
there had to be a reason). However, for low-probability events
to appear nonrandom a nonrandom explanation has to be
available. Thus, unexpected grades (Experiment 6a) are easier
Table 4 Mean probability estimates and randomness scores (with mean
absolute deviations [MAD]) for poor exam grades and lottery wins,
Experiments 6a and 6b
Scenario Probability (1–7) Randomness (1–7)
Mean score Mean score MAD
Exam scenario (6a)
Two poorer grades (Ann) 3.34 a 3.16 a 1.36 a
Two failed grades (Carol) 1.93 b 3.24 a 2.02 b
Lottery scenario (6b) Objective probability
One win 1/20 6.29 b 0.88 c
Two wins 1/400 6.11 b 1.06 d
Note. Numbers with different subscripts in each column are significantly
different from each other (p < .001 for Experiment 6a and p < .05 for
Experiment 6b)
perceived as nonrandom than unexpected lottery results
(Experiment 6b).

Comparing our results with randomness judgments performed within the binary sequence paradigm, a striking contrast can be observed. In these studies patterns were judged
less random when they were perceived as unlikely outputs
from a series of tosses by a coin. In Falk and Konold’s
(1997) studies, ratings of “apparent randomness” were in fact
obtained by asking participants about the likelihood of achieving particular sequences randomly, and then concluding that
unlikely outcomes meant not random. Our studies indicate the
opposite—namely, that for singular events in daily life,
unlikely indicates more random. These differences suggest
that studies of binary sequences have limitations as a universal
model of the perception of randomness (see also Matthews,
2013, on the evaluation of streaks of different kinds).
These evaluations are not as incompatible as they may
seem. Judgments of randomness in sequences assume the existence of a random generator producing inchoate strings,
where order is “surprising” (Feldman, 2004) and anomalous.
Participants in these tasks make judgments based on an assumption of disorder, where observations of irregularity are
expected and, in a way, considered as default. Outside of this
rather artificial universe, however, people will look for, and
expect, some degree of predictability and order. They will find
irregular events to be the exception rather than the rule, and
only draw conclusions about randomness in the “unlikely”
case of aberrant events that cannot be predicted. By this epistemic attitude they manage to preserve a model of the world
as basically orderly and explainable.
In the present studies, we have compared participants’ solutions to a task of predicting outcomes (probability estimates)
with a task of postdicting hypotheses (randomness ratings). In
terms of conditional probabilities, this changed their task from
considering p(data | H) to expressing their opinions about the
inverse relationship p(H | Data). To do so in a meaningful way,
one needs to have an idea not only about p(data | H), but also
about the prior probability of potential alternative hypotheses,
and how compatible the actual outcomes are with both alternative hypotheses, as required by Bayes’s theorem. It is reasonable to assume that a search for alternative hypotheses will
emerge when p(data | H) is quite low, unless the process is so
well described that the role of other contributing causes can be
controlled for. To illustrate, the winner of the lottery in
Experiment 1a had only 10% chance, yet the fact that he
won could not rule out randomness, as the process of a blind
draw did not allow the winning to be explained in any other
way. This was replicated in Experiments 1b and 6b with even
lower probabilities. In contrast, the factors responsible for the
outcome of a soccer match include situational determinants
and skills, making it easier to produce a narrative that highlights factors different from randomness. So, when an extraordinary and unlikely 5-0 outcome happens, some participants
decided to look for potential reasons that made this result
appear more plausible, and hence less random than before.
These apparently divergent judgments do not invalidate the
link between low probability and high perceived randomness,
as they may simply stem from an attempt to think that extraordinary outcomes must be due to an overriding cause, making
them more likely (and less random) than originally assumed.
A similar process can be observed when exceptional coincidences are “explained” by recourse to magical or supernatural
forces. They then become more likely (and not random) by
means of an unlikely (magical) theory of coincidences
(Griffiths & Tenenbaum, 2007).
We do not claim that all low-probability events will be
regarded as random, and certainly not that probability is the
only determinant for attributing an outcome to randomness, or
chance. Other potential determinants of randomness could be
examined by manipulating other variables—for instance,
causal factors, skill, intentionality, and effort. Our results indicate that low probabilities constitute one (supposedly important) facet in the perception of randomness, though we do not
claim that it is the only one.
Why should low p events be regarded as more random? Low
p events need not be uncaused or unintentional, and even quite
infrequent happenings (like Halley’s comet appearing once in
75 years) can form a pattern. We propose that the answer may
reside in two related characteristics of subjective randomness.
People consider an event as random if it appears as
disconnected from the general flow of events, like an unmotivated cough in the middle of a sentence or an unexpected computer crash before the document is saved. In these cases, the
“random” events cannot be conceived as causally related to the
main story line. It is also in the nature of such events to be
unforeseeable. They are deviant and form exceptions to the rule.
By this logic, it was less foreseeable (and more random) that
Karl in Experiment 1 drew a winning marble from his 10% urn
than John did, as John’s urn contained 90% winning marbles.
Indeed, unpredictability has been suggested as an optional
definition of randomness—for instance, as independence (zero autocorrelations) between the parts of a random sequence,
where one part cannot be predicted from preceding parts
(Neuringer, 1986; Nickerson, 2002). Also, in the case of blind
draws from an urn with unequal frequency of different colors,
all marbles (but not all colors) have the same probability of
being chosen, implying unpredictability on the level of individual marbles (but not on the level of colors). Our participants appear to go one step further and reason that degree of
randomness depends on outcome features: a drawing of the
dominant color is less random, by being more expected than
other colors.
The present studies did not instruct participants as to what
should be meant by a random or a nonrandom outcome. This
was done deliberately, in order to avoid directing our respondents towards a specific interpretation of the term. Like
probability, randomness is a polysemous concept (Hertwig &
Gigerenzer, 1999), having multiple, related meanings.
Accordingly, we do not claim that this term was used by all
participants in exactly the same way. Notwithstanding, the
results showed a remarkable consistency of low-probability
events being rated as being more random across a wide range
of situations with speakers of two different languages.
The idea that random events are rare can have several important implications. One is exaggerated beliefs in foreseeability and control, as indicated by research on the hindsight bias
(Roese & Vohs, 2012). It might reinforce a preference for
intentional rather than accidental explanations of behaviour
as demonstrated by studies of the “intentionality bias”
(Reich, Kupor & Smith, 2018; Rosset, 2008). It may lead
historians, social scientists, and psychologists to underestimate the role of randomness in shaping individual and collective history (Krantz, 1998; Sunstein, 2015), and make them
look for patterns, plans, and explanations behind phenomena
that cannot be adequately attributed to single causes or to a
purposeful design.
An association between randomness and low probability
may suggest that random events are in themselves
insignificant and do not, as a rule, give rise to important
changes. As John Stuart Mill (1856) observed, people tend to
think that effects share important characteristics with their
causes; large effects are supposed to have large causes, and evil
effects are supposed to flow from evil forces (Nisbett & Ross,
1980). By a similar logic, one may believe that random and
unlikely events can be taken lightly, if they have only in their
power to produce slight and insignificant consequences. What
people think about the “magnitude” of random events and their
potential causal power has been recently been examined by
Teigen and Kanten (2019). Their perceived low probability
suggests that they can be easily ignored or discounted as “exceptions.” Correspondingly, one rarely stops to consider whether frequent or more noteworthy events could be due to chance.

Fisher's lost model of runaway sexual selection: Sexy sons theory survives math modeling better than good genes theory

Fisher's lost model of runaway sexual selection. Jonathan M. Henshaw  Adam G. Jones. Evolution, December 30 2019.

Abstract: The bizarre elaboration of sexually selected traits like the peacock's tail was a puzzle to Charles Darwin and his 19th century followers. Ronald A. Fisher crafted an ingenious solution in the 1930s, positing that female preferences would become genetically correlated with preferred traits due to non‐random mating. These genetic correlations would translate selection for preferred traits into selection for stronger preferences, leading to a self‐reinforcing process of ever‐elaborating traits and preferences. It is widely believed that Fisher provided only a verbal model of this ‘runaway’ process. However, in correspondence with Charles Galton Darwin, Fisher also laid out a simple mathematical model, which purportedly confirms his verbal prediction of runaway sexual selection. Unfortunately, Fisher's model contains inconsistencies that render his quantitative conclusions inaccurate. Here we correct Fisher's model and show that it contains all the ingredients of a working runaway process. We derive quantitative predictions of his model using numerical techniques that were unavailable in Fisher's time. Depending on parameter values, mean traits and preferences may increase until genetic variance is depleted by selection, exaggerate exponentially while their variances remain stable, or both means and variances may increase super‐exponentially. We thus present the earliest mathematical model of runaway sexual selection.

Check also Meta-Analysis Suggests Choosy Females Get Sexy Sons More Than 'Good Genes'. Zofia M. Prokop, Łukasz Michalczyk, Szymon M. Drobniak, Magdalena Herdegen, Jacek Radwan. Evolution,

Menopause may be the result of the accumulation of infertility mutations in older women due to men’s preference for younger mates;it can de-evolve, be delayed and even disappear, in theory

Is menopause still evolving? Evidence from a longitudinal study of multiethnic populations and its relevance to women's health. Rama Shankar Singh, Shirley Chan, Alyssa Gomes. BMC Women's Health, Dec 26 2019 (under review). DOI:10.21203/rs.2.19623/v1

Abstract: To reflect on the impact of changing patterns of delayed marriage and reproduction and to seek evidence as to whether menopause is still evolving, characteristics of the menopause transition were investigated within and between ethnic populations in this study. A cross-sectional analysis was conducted using data on 747 middle-aged women obtained from the Study of Women’s Health Across the Nation (SWAN) from 1996 to 2008. The ethnic groups included: Afro-American, Chinese, Japanese, Caucasian, and Hispanic. Perimenopause age and duration, menopause age, and hormonal indicators of menopause were examined across five ethnicities. We found a similar window of menopause age within populations, but no significant difference in perimenopause and menopause age between populations. The rate of increase of follicle-stimulating hormone and testosterone differed significantly in Hispanics and African-Americans during the menopause transition period. The broad window of variation in age at menopause within the population (45-60 years) and the absence of significant differences between populations, in combination with population variation in menopause symptoms, suggest that menopause is a relatively recently evolved and still evolving trait. Under the mate choice theory of menopause, menopause is the result of the accumulation of infertility mutations in older women due to men’s preference for younger mates. We propose a shifting mate choice-shifting menopause model which posits that, as the age of mate choice/marriage shifts to older age, so will the age at menopause, and that menopause is a transient phase of female fertility; it can de-evolve, be delayed and even disappear, in theory.

KEYWORDS: Mate choice, menopause, perimenopause, sex-hormones, menstruation


Insight into the association between ethnic diversity and the characteristics of a woman’s menopause transition may provide evidence for the timing of the appearance of menopause in human evolution. In this study, we evaluated perimenopause and menopause age, perimenopause duration, and the associated reproductive hormonal changes in a longitudinal, multi-ethnic sample from the cross-sectional study SWAN9. While the results of this study revealed lack of a consistent ethnicity-specific difference in the timing of the menopause transition, there were significant changes in the associated hormones which, together with variations within populations in the menopause “window” and population-specific variation in menopausal symptoms, are suggestive of menopause as a recently evolved and still evolving trait in human evolution.
Before discussing the significance of these results, it is important to state the rationale for this study. From the women’s health point of view, it is important to know if menopause is still evolving and, if so, can it de-evolve, i.e. can it be delayed or even eliminated. To be able answer this question, we need to know the nature of variation in menopause. The SWAN study (and many others reviewed by Gold et al.9) looked into the effect of lifestyle factors on menopause. Controlling for sociodemographic, lifestyle, and health factors affecting the final menstrual period (FMP), Gold et al.9 found that “racial/ethnic groups did not differ in age at the FMP. Higher educational level, prior oral contraceptive use, and higher weight at baseline, as well as being employed, not smoking, consuming alcohol, having less physical activity, and having better self-rated health over follow-up, were significantly associated with later age at the FMP”. These results suggest that menopause is a complex trait, but it is interesting to note that, in spite of the effect of socioeconomic factors, the onset-age “window” of menopause remains more or less stable from population to population (Fig. 2). Our reduced data set was designed to increase the chances of discovering ethnic differences in the onset age of menopause; we found it to vary significantly in Hispanic population only. In the following, we review our findings and use them to propose a model of “shifting mate choice-shifting menopause” and predict that there is population variation in the onset age of perimenopause and that the shifting patterns of mate choice and marriage will lead to a shift, a delay in the onset age of menopause.

Ethnic variation in perimenopause age
At present, this is the first assessment of the age of perimenopause onset in a multi-ethnic sample. This study has identified a significantly earlier perimenopause onset in women of Hispanic descent compared to women of Caucasian, African-American, Chinese, and Japanese descent. Hispanics experience perimenopause approximately two years earlier, which suggests that changes in the reproductive systems are still taking place and that menopause has not stopped evolving separately in each population. While this result may be suspect because of small sample size and heterogeneity among samples originating from different Central American countries, as we show below, other studies have reported similar results.
Previous perimenopause literature is highly limited. Mentions of perimenopause age in other literature are either not quantified or they refer to the mean age of women in the perimenopause cohort, rather than onset age. Of the feasible literature, McKinlay et al.27 has reported the inception of perimenopause to be 47.5 years, earlier than determined in our study (51.8 years). It should be noted that McKinlay et al.’s27 perimenopause age was not specific to any ethnicity and was limited to women in Massachusetts. Sammel et al.28 also examined the menopause transition across ethnicities, albeit limited to Caucasians and African-Americans. The specific age was not listed, but it was found that African-American women entered perimenopause earlier than Caucasians, a finding that was not observed in this study28. Differences in the reported age in McKinlay et al.’s27 study and the variation in African-American and Caucasian women perimenopause age of onset in Sammel et al.’s28 study can be attributed to definition bias introduced in our study. Other studies define perimenopause onset using early perimenopause (menstrual irregularity). In contrast, we used late perimenopause (3 to 11 months of amenorrhea) due to a change in the questionnaire following the 1997–1999 follow-up (SWAN), which led to overestimation of perimenopause onset age. It is likely that a change in perimenopause definition will yield results similar to other studies, as our results are consistent with Sammel et al.’s28 finding that entry into late perimenopause did not differ significantly between African-American and Caucasian women. Although it is probable that the definition of perimenopause influenced observed trends, it is likely that an ethnic variation in perimenopausal age exists. Perimenopause age in Indian women was reported to be 44.69 years, which is prominently earlier than any reported perimenopause age for US women as a whole and thus suggestive of differential biological timing of perimenopause present among populations29. More studies with diverse population samples are needed.

Ethnic variation in menopause age
In agreement with wide variation in menopause age across women worldwide, heterogeneity in menopausal age among ethnicities was found only in Hispanics in our study. Hispanic women experienced menopause two years earlier than women of other ethnicities, which mimics the results found for perimenopause age. Again, this result may due to small sample size, but several studies have reported a two year difference in menopausal age between Hispanic and Caucasian women30 − 32. Age of menopause in Hispanic populations has been reported at 48.5 years for 15 countries across Latin America and 47.9 years in Mexican women, whereas Caucasian populations experience menopause at 50 years33, 34. Despite the higher menopausal age recorded in this study (51 vs. 53 years; Fig. 2), which was attributed to differences in methodology, our findings support previous literature. Furthermore, we suggest this difference is unlikely to be the result of lifestyle factors such as smoking prevalence, which accelerates menopause by 1–2 years27, 32, 35. Previous analysis of SWAN participants have shown that smoking frequency was lower among Hispanics than Caucasians and African Americans, which was consistent with other studies36, 37. Hence, the earlier onset in Hispanic women may be due to a different biological clock for the timing of menopause onset compared to other ethnicities.
Studies of candidate gene polymorphisms affecting menopausal age have found that the rs16991615 SNP in MCM8 locus, a gene involved in the repair of double-stranded DNA breaks reduces age at menopause by 2.3 years for Hispanic women38. The samers16991615 SNP exerts the opposite result in Caucasian women, increasing menopausal age by 0.82 years39. The effect of an SNP may vary according to ethnicity, which suggests that menopause may have co-opted different genes in ancestral Hispanic populations.
Whether a difference in menopausal age between African-Americans and Caucasians exists is unclear. Bromberger et al.35 proposed that African-American women experience menopause six months to a year earlier than Caucasian women. This seems plausible given that studies of African women, specifically from Ghana and Nigeria, determined that menopause occurred at 48–49 years, which is earlier than Caucasian women30,32,34. In contrast, several studies did not report differences in menopausal age between Caucasians and African-Americans28,30,31. Our findings support the latter, as both the mean and median menopausal age in both ethnicities was similar. It is possible that the small African American sample size (n = 19) and high percentage of smokers could have contributed to Bromberger et al.’s35 observations.
The similarity in menopausal age observed in both African-American and Caucasian women led us to expect similar evolution of menopause in their ancestral populations. Interestingly, however, many of the Caucasian associated SNPs studied in candidate gene polymorphisms associated with menopause age were poorly replicated or not replicable in African-Americans in GWAS studies, which suggest that African-Americans are not as similar to Caucasians as initially believed39,41. Given the high linkage disequilibrium, African-Americans were suggested to have a variant of the SNP at the associated loci, although it was not identified39, 41. If variants exist in African-Americans, it is possible that the effect of the variant would be similar to the Caucasian SNP to result in the similar phenotype (i.e. menopause age) observed between these two ethnicities. This seems plausible since the SNP findings were able to be replicated in African Americans, such as the rs365132 SNP at the UIMC1 locus, with effects similar to Caucasians (i.e. increased menopausal age by ~ 0.4 years)41. Further research is required to determine the variation between Caucasians and African-Americans, as SNPs associated with menopause onset in African-Americans have not been well-studied.
Menopausal age for Chinese women from China and Singapore and Japanese women from Japan was roughly 50 years in both populations, which resembles the Caucasian menopausal age34,41,44. Concurrent with our results, similarity in menopausal age between Caucasian, Chinese, and Japanese women have been reported in the literature42,45−47. Several SNPs associated with menopausal age in Caucasians were replicated to the same effect and direction in Chinese women from Shanghai, suggesting that there are some shared menopausal evolutionary traits between these two ethnicities48.
Recent studies have suggested that Japanese women entered menopause at later ages than Caucasian women28,30,31,37. While the mean menopausal age did not differ significantly between Caucasian and Japanese women in our study, we did observe a higher percentage of Japanese women entering perimenopause and menopause later than other ethnicities, which supports past findings28,30,31,37. If differences in menopause age exist between the two ethnicities, this may indicate differences in menopause affecting loci. One study reported several SNPs associated with menopause age in Caucasians could not be replicated in Japanese women in GWAS studies; however this was a very small study39. Further research is needed to determine whether or not Caucasian SNPs can actually be replicated in Japanese women or whether other variants exist.

Ethnic variation in the duration length of perimenopause
This is also the first study reporting the duration of perimenopause among different ethnic groups. In spite of the heterogeneity in the timing of the menopause transition, our findings show that the length of perimenopause was consistent across all ethnicities (Fig. 4). The duration of perimenopause appears negatively correlated with the age of menopause. This result presents the possibility that the intrinsic mechanisms underlying the progressive loss in ovarian function from the perimenopause to menopause stage is shared among individuals. Combined with the data for timing of the menopause transition, it is hypothesized that the timing of onset is what separates the menopause phenotype between ethnicities, as opposed to the duration. Future research can be directed to understanding why and how the timing of menopause has been shifted in different populations over the course of human evolution to result in the current ethnic variation in the onset of the menopause transition. One evolutionary theory explores the idea that women of ancestral populations with lower female biased dispersal would experience earlier menopause, although the required information about ancestral ecologies in these populations is lacking49.
McKinlay et al.27 determined the length of perimenopause to be 3.7 years, which was markedly higher than the 1.3 years reported in this study. Again, this can be partly attributed to the definition bias of perimenopause, which would have led to an underestimation of the perimenopause duration in this study (Fig. 4). Alternatively, the methodological differences used to determine the duration was also a factor. For example, McKinlay et al.27 determined duration by subtracting the mean age of menopause from perimenopause onset. This could lead to under/overestimation of the duration since it was not representative of the duration in individuals. There is individual variation in duration of perimenopause; hence, the duration should be determined by averaging the duration in each individual, which was done in this study. Future studies in perimenopause length are encouraged to average individual duration for greater accuracy of the duration. Additionally, further research is needed to determine if the similarity in duration in ethnic groups still exists when early perimenopause is used to define perimenopause onset, as opposed to late perimenopause.

Ethnic variation in hormone concentrations
Across all ethnicities, E2 concentrations declined over the menopause transition, as expected. As the menopause transition progresses, there is progressive loss of ovarian follicles, which produces E2, leading to overall reduced E2 levels32. Consistent with studies conducted by Randolph et al. [50] and Kim et al.51, mean E2 levels did not differ significantly across ethnicities. Similarities between E2 levels across ethnicities may be linked to earlier observations of the perimenopause duration. Klaiber et al.52 noted that women with lower E2 levels had shorter menopause transition duration. Since all ethnicities were similar in E2 levels, the duration was not expected to differ between ethnicities, which are consistent with our results.
Since changes in E2 are correlated to changes in FSH, we did not expect differences in serum FSH across ethnicities either. However, we found a significantly lower FSH increase in Hispanics and African-Americans compared to other ethnicities during the menopause transition. These ethnic differences in FSH levels were thought to be linked to ethnic variation in pituitary-ovarian feedback during the menopause transition, such as variation in estrogen sensitivity53 − 55. Greater sensitivity to estrogen decline is associated with higher FSH levels, as estrogen is a negative regulator of FSH. Examination of polymorphisms in ESR1, which codes for an estrogen receptor, has shown that the rs2234693 polymorphism was significantly associated with Caucasian women menopause onset, although further research is needed for other ethnicities56. In contrast, other studies have reported higher FSH levels in Hispanics and African-Americans, regardless of menopausal status50,53. This was attributed to the lack of adjusted BMI hormonal values in our study and different hormonal collection times. Fundamentally, both our results and Randolph et al.’s50,53 have consistently noted an ethnic difference in FSH levels.
Similar to FSH levels, there was an ethnic difference in the increase of T levels across the menopause transition. Premenopausal T concentrations did not vary among ethnicities, but in menopausal women, T was significantly higher in Hispanic and African-American women compared to other ethnicities, suggestive of ethnic differences in T metabolism over the menopause transition. Literature to support this observation is scarce because T assays have difficulties reporting the low T concentrations in women, making it challenging to study in menopausal women57. A study by Luckey et al.’s58 provides a possible indicator of ethnic differences in T metabolism by examining rates of bone loss during the menopause transition, as lower T levels are suggested to contribute to greater bone loss. In Luckey et al.’s58 study, African-American women were found to have lower rates of bone loss than white women, suggestive of higher T levels in African-Americans, which is consistent with our findings in this study. Other studies have found lower T levels for African-Americans and Hispanics compared to other ethnicities, which was attributed to BMI adjusted values50,51. Overall, we can affirm that ethnic variation for T levels exists.
Several studies have correlated changes in SHBG to changes in T, which may suggest that ethnic differences in T could be attributed to ethnic differences in SHBG during the menopause transition59,60. This was unlikely given that ethnic differences in SHBG in menopausal women and SHBG rate of increase over the menopause transition were not observed, which was consistent with findings from Burger et al.59. Alternatively, studies have found associations between DHAS and T, which may also suggest ethnic differences in DHAS as a factor for ethnic differences in T60,61. While ethnic differences were noted in DHAS levels in both premenopausal women and menopausal women, no ethnic differences were found in the rate of DHAS increase. Similar findings have also been reported in other studies59. It thus seems that ethnic differences in DHAS changes are not specifically associated with the menopause transition, and is unlikely to be the cause of ethnic differences in T during the menopause transition, so other factors are likely responsible for the ethnic differences in T changes. One possibility involves androstenediol, which is secreted similarly to DHAS during the menopause transition62. Its concentrations are thought to affect the balance of androgens over the menopause transition, hence research determining if ethnic differences exist for androstenediol, along with other possibilities for the ethnic differences in T, would be beneficial62.
As mentioned before, there are several limitations to this study. The first is regarding the participants. The age of participants was limited to 42–55 years, which may have biased the perimenopause and menopause age to older ages. This may not be a significant limitation, given that, in a study done by Luborsky et al.37, they reported ethnic variation in premature menopause (menopause age < 40 years) consistent with our study. The exclusion of women with inconsistent bleeding patterns in this study could also have biased the results. Although not shown, we retested our findings with these exceptions added, but overall the findings remained the same. Secondly, late perimenopause was used to define perimenopause onset, leading to an overestimation of perimenopause age, underestimation of menopause duration, and irregularity in premenopausal hormone values. Additionally, use of BMI adjusted hormonal values could have altered our findings, as BMI has been shown to affect hormonal values significantly, positively for T and negatively for all other tested hormonal values53. It is also possible that hormone therapy could have interfered with our findings; however, as explored by Kim et al.51, hormone therapy does not deviate from the results comparing ethnicities; rather, it only reduces the differences between groups.

A “shifting mate choice-shifting menopause” model of female fertility
The main results regarding variation in age of menopause, from this study as well as others, can be summarized as follows. Firstly, all human populations, regardless of socioeconomic status, show a roughly 15-year window of menopause45 − 60, which means that there is plenty of variation within populations. Secondly, many lifestyle factors are known to affect the age of menopause, but with the exception of premature menopause, the menopause window persists in all populations. Thirdly, there are no significant ethnic differences in the onset age of perimenopause, presumably because there has not been sufficient time since the origin of menopause to produce such differences. Furthermore, as we show below, the absence of variation among populations may indicate the role of similar mate choice mechanisms (i.e. male preference for younger mates) operating in all human populations. Fourth, there are significant changes in the levels of associated hormones within as well as between populations. Finally, different populations show ethnicity/race-specific menopause symptoms; for example, vasomotor symptoms were more common in Afro-American and Hispanic women than in other ethnicities63. This suggests a role of both biological and cultural factors. We take these results to mean that menopause is a relatively recent trait, and most variation in the trait is present within populations with relatively little variation between populations. This is not surprising in view of what is known about human genetic variation in general19.
We use these results to extend the mate choice theory of menopause10, which holds that menopause is the result of men’s preference for younger mates, leading to the accumulation of deleterious mutations affecting fertility in women deprived of reproduction. We propose (1) that the present menopause window (roughly 45–60 years) is directly related to the “mate choice window” in the present-day human population (roughly 15–30 years); (2) that the lack of between-variation in perimenopause is the result of a similar mate choice system operating in all human populations; and (3) that changing patterns of mate choice/marriage will ultimately lead to a shift in the onset age of menopause. This shift will not occur immediately as the pressure from the shifting mate choice will only have its effect if women of premenopausal age will choose to engage in reproduction. Under the mate choice theory, menopause is a transient phase of male-imposed female fertility and it will be delayed with changing patterns of delayed mate choice/marriage and reproduction.

Older Brothers and Male Homosexuality: Antibodies as an Explanation

Older Brothers and Male Homosexuality: Antibodies as an Explanation. T.S. Sathyanarayana Rao, Chittaranjan Andrade. Journal of Psychosexual Health, August 9, 2019.

The familial nature of homosexuality in men has been known for decades.1 The finding is gender-specific; homosexual men have a higher proportion of homosexual brothers than heterosexual men, but not a higher proportion of homosexual sisters.2

It has also been known for decades that homosexual men have a lower birth order, on average, than heterosexual men.3, 4 More specifically, homosexual men have a greater number of older brothers but not older sisters, younger brothers, or younger sisters.5

The evidence for the fraternal birth order effect is strong. There is a very large number of studies on the subject, and these studies have been subjected to meta-analysis. In this meta-analysis,6 the strength of the effect in persons from small versus large families and in homosexual males with masculine gender identities versus those with feminine gender identities were compared.

The meta-analysis included 30 homosexual and 30 heterosexual groups from 26 studies. The pooled sample included 7140 homosexual and 12,837 heterosexual males. The outcome variable of interest, the older brothers odds ratio (OR), was calculated as follows:

First, an older brothers ratio was calculated for homosexuals and heterosexuals separately. This value was the number of older brothers divided by the number of all other siblings.

Next, the older brothers OR was calculated as the older brothers ratio in homosexuals divided by that in heterosexuals. This OR is interpreted in the conventional way; a value of 1 indicates no fraternal birth order effect and values >1 indicate support for the fraternal birth order hypothesis.

Important findings from the meta-analysis are presented in Box 1. In summary, the meta-analysis found that having a larger number of older brothers was associated with a significantly increased risk of homosexual orientation, especially feminine or transgender homosexual orientation. This fraternal birth order effect was unrelated to family size. Of interest, the meta-analysis also found that only about 15% to 29% of men in any given homosexual group could attribute their sexual orientation to the fraternal birth order effect.

Why should having (more) older brothers increase the risk of homosexuality in men? A superficially plausible explanation is that fraternal sexual exposure or experimentation in childhood may behaviorally prime individuals towards a homosexual orientation. This explanation fails because it does not explain why having younger brothers does not predispose to male homosexuality or why the same-sex sibling effect does not exist for women.

The fraternal birth order effect has therefore led to a search for biological explanations, and an in utero maternal immune response has been suggested.7, 8 In this context, Bogaert et al.9 examined plasma from mothers of male offspring about half of whom had a gay son, and controls, comprising men as well as women with no sons. They used immune assays to study whether mothers develop antibodies against two Y-linked proteins that are important in male brain development in utero, and whether this effect strengthens with succeeding male gestations. The proteins that they studied were protocadherin 11 Y-linked (PCDH11Y) and neuroligin 4 Y-linked (NLGN4Y; isoforms 1 and 2).

Important findings from the study of Bogaert et al.9 are presented in Box 2. In summary, the findings suggested that the maternal immune response against a Y-linked protein (that is important in male brain development in utero) is associated with homosexual orientation in sons. This protein, the NLGN4Y protein, is a cell-adhesion protein that plays a vital role in cell-cell interactions, specifically in the process of synapse formation, during in utero neurodevelopment.7

At the risk of stating the obvious, it must be noted that the development of sexual orientation is multifactorial and depends on biological and social influences from the womb through early life. Nevertheless, if an antibody response can be confirmed as an etiological factor, might primary prevention interventions be possible?

There is a positive relation between the personal importance that subjects attribute to a moral issue and the objectivity they bestow to it; presenting moral demands as objective may be instrumental to the function of choosing sides in moral debate

Hopster, Jeroen and Klenk, Michael, Evolution and the Objectivity of Moral Judgments (December 9, 2019). SSRN:

Abstract: Can findings from experimental and evolutionary psychology help to adjudicate the debate between moral realism and moral antirealism? In this article we address this question from two angles. First, we present the results of an experiment in moral psychology we have conducted, which shows that there is a positive relation between respondents’ ratings of the ‘personal importance’ and the ‘objectivity’ attributed to moral issues. Second, we discuss these results in the context of a recent hypothesis from evolutionary psychology, according to which objectifying moral issues serves a signaling function: agents present moral issues as objective to flag that they find these issues important. Does this hypothesis, if correct, have any metaethical implications? We acknowledge some of the pitfalls in drawing robust metaethical conclusions from this body of work, but argue that it is metaethically relevant nonetheless: it overturns a key desideratum of metaethical analysis in a realist-unfriendly way.

Keywords: Metaethics, moral psychology, experimental psychology, folk objectivity, evolutionary debunking arguments, social consensus, personal importance, signalling, choosing sides

4. General Discussion: The Psychosocial and Evolutionary Functions of Objectifying Morality

In the previous section we presented experimental evidence which suggests that personal
importance is one of the determinants of regarding moral statements as objective. In this section
we turn to the question of what psychosocial function objectifying moral issues might serve,
and what this function might tell us about morality’s evolutionary origins. Objectifying moral
demands may serve multiple psychosocial functions; here we will highlight some of the
functions that we think are particularly prevalent. While these proposals are not directly
implied by our experimental work, they have a good fit with our experimental findings.

4.1 What Is the Function of Externalizing Moral Demands?
Perhaps the first metaethicist to suggest that objectifying moral judgments serves a
psychosocial function was John Mackie (1977). According to Mackie, it often serves
interpersonal relations well to behave as morality requires: ‘We need morality to regulate
interpersonal relations, to control some of the ways in which people behave towards one
another, often in opposition to contrary inclinations. We therefore want our moral judgments
to be authoritative’ (1977 p. 43). Think of situations which involve a tragedy of the commons:
to coordinate action by referring to common moral values might help to solve social
Why should moral values be regarded as objective to serve this function? Followers of
Mackie, such as Joyce (2006), have argued that objectifying moral demands has a motivational
upshot: feeling an internal sense of moral obligation motivates us to behave as morality
requires. Perhaps this is part of the explanation, but as Stanford (2018) has recently argued, it
cannot be the full story. We are also motivated by subjective experiences, such as the
experience of pain or hunger, which we do not cast in terms of having an external authority.
What additional function is served by supposing moral demands to be objective?
Wright et al. (2013; 2014) have formulated a hypothesis about the psychosocial
function of moral objectivism that may answer this question. Building on experimental findings
which suggest that subjects’ attitudes towards regarding moral issues as objective is quite
flexible and diverse, they suggest that a capacity to modulate the objectivity ascribed to moral
issues helps to coordinate dialogue and action both within and between sociocultural groups
(Wright, McWhite, Grandjean 2014 p. 31):
Viewing a moral issue as objectively grounded removes it from the realm of legitimate
personal/social negotiation (…). Viewing a moral issue as non-objectively grounded,
on the other hand, allows people to acknowledge its moral significance (…), while at
the same time maintaining room for choice, dialogue, and debate.
We think that Wright et al.’s hypothesis is along the right lines: presenting a moral
demand as objective typically signals an unwillingness of the agent making the demand to
easily change her mind about it. But we disagree that objectifying moral issues removes them
from the realm of legitimate negotiation. More plausibly, we think, an ascription of objectivity
serves to signal on which topics agents are willing to stand their ground in moral discussion.
This function, in turn, is at least partly modulated by what issues agents find important, as our
experimental results suggest. Presenting an issue as objective typically signals that agents are
willing to stand their ground in moral debate, often with regard to issues which they judge to
be of specific personal importance.

4.2 Moral Objectification: A Signalling Hypothesis
Our signalling hypothesis contrasts with the view that the function of objectifying moral
judgments serves the function of moral persuasion. As Mercier, Sperber (2017) argue,
discussions typically do not serve to grasp truths but to persuade other parties. We grant that
the same might typically be true for moral discussions, but we do not think that this is the main
function of presenting moral issues as objective. Rather than dialectical effectiveness – i.e. an
ability to efficaciously change other people’s minds – we think that objectifying moral issues
typically serves to signal that agents care about an issue and are not easily prepared to change
their minds about it. In doing so they give others a choice: on this issue you’re either with me,
or against me. Hence, presenting moral issues as objective may be an effective means to form
moral alliances, to enhance in-group cohesion and to demarcate the out-group.
Our signalling hypothesis also contrasts with the view that moral objectification is
mostly due to conformity bias. We do not deny that conformity bias may play a role in moral
decision-making, but hypothesize that when issues are presented as objective, this is typically
not due to an agent seeking conformity. Rather than siding with the majority, presenting a
moral issue as objective serves to signal agents’ personal commitment to the issue and their
willingness to stand their ground, even in the face of contrary moral viewpoints and regardless
of the consensus view. Perhaps signalling this commitment is specifically beneficial if a moral
stance is a minority view: it allows fellow activists to rally support for specific moral issues
irrespective of what the majority says.

4.3 Choosing Sides
Two of the features of moral objectification outlined in the previous subsection – objectifying
moral issues often instigates third parties to choose sides, and often does so on the basis of the
contents of specific issues rather than majority consensus – are congruent with a recent
evolutionary hypothesis by DeScioli, Kurzban (2013), who have argued in detail in support of
the thesis that the main evolutionary function of moral judgment is choosing sides in conflict.
Choosing sides is a strategic interaction problem that involves a perpetrator, a victim and a
third-party condemner. Different solutions are possible, some which involve decision
procedures that would never be advisable in making individual choices, but may be beneficial
in multiplayer interactions.
One possible solution is to choose sides on the basis of pre-existing alliances. However,
this strategy has the downside of escalating conflicts, resulting in greater fighting costs. A
second solution is to choose sides on the basis of power: third parties side with the most
powerful party in the conflict. However, this strategy has the downside of concentrating power
in the hands of high-status individuals and may lead to authoritarianism and exploitation. A
third solution is to choose sides by focusing on the contents of an action. Some actions may be
flagged as never–to-be-done or categorically wrong; this public signal can subsequently
coordinate third-party judgment. This solution is characteristic of moral conflicts, in which
bystanders typically coordinate which side they choose not on the basis of the identities of the
disputants but on the basis of their actions. Indeed, some characteristic features of morality –
its impartiality, non-consequentialist characteristics and the categorical nature of moral
demands – can be explained by this strategic interaction framework.
Our hypothesis fits well with that of DeScioli, Kurzban (2013) and extends it to the
metaethical domain. We think that objectifying moral issues is instrumental to the function of
choosing sides. For parties engaged in conflict, presenting an issue as objective serves as an
effective instrument to force third parties to choose sides in the debate. By objectifying an
issue, members of the party engaged in conflict signal their intention to stand their ground, and
force bystanders to choose: on this issue they are either with them, or against them.

5. A Challenge for Moral Realism from Evolutionary Psychology?

In this article we have highlighted recent experimental findings from moral psychology,
including those of our own, as well hypotheses from moral psychology concerning the
psychosocial and evolutionary functions of moral objectivism. Let’s assume that they are along
the right lines. Do they have any implication for metaethics? More specifically, do they give
rise to a challenge for moral realism, which does not face the same objections as Ruse’s EDA
(subsection 1.2)?
We think they do – not by debunking realism, but by challenging the presumptive
assumption of realism based on the phenomenological claim. Recall that realists typically
support their position by appealing to the seeming objectivity of moral demands (e.g. Brink
1989; Enoch 2015).7 As noted, recent experimental findings do not straightforwardly vindicate
the assumption that moral demands are conceived as objective in the realist’s sense. Moreover,
to the extent that moral demands are conceived as strongly objective, we have provided
evidence that this is plausibly regarded as an artefact of our psychology, and that our tendency
to objectify moral demands can be understood in evolutionary terms. This does not establish
that the objectivity of moral demands is merely an illusion, as Ruse argues, but it does serve to
undercut the presumptive support that our moral phenomenology bestows upon moral realism
– which, as mentioned, is one of the main arguments that realists have traditionally provided
in support of their view.

Differently put, the findings we have presented serve to undercut the validity of the
desideratum that metaethicists should vindicate the ‘objective seemings’ of our moral
experience. To the extent that this objectivist phenomenology is real, debunkers can argue that
our perceived sense of moral objectivity can be explained in evolutionary terms. The upshot is
that, whether or not moral realism is ultimately tenable, it need not be regarded as the default
position in metaethics, as its defenders typically suggest (e.g. Enoch 2015). For those who think
that realism is the ‘view to beat’ in metaethics, our conclusion provides an important change
to the dialectic of the debate.
In closing, let us point out exactly how the relation between scientific findings and their
metaethical implications should be understood, in the context of the case-study we have
presented. Underlying the presumptive assumption of moral realism is an inference to the best
explanation: a realist metaethics provides the best explanation for the ‘datum’ that moral
demands are typically regarded as strongly objective (a datum that was originally assumed
from the armchair, and that has subsequently been partly corroborated by experimental work).
Realists present a metaethical explanation to account for this datum: we think of moral
demands as objective, because we have some intuitive grasp of a stance-independent moral
reality. This is not the only kind of explanation that could be advanced, however. For instance,
the datum could also be explained in scientific terms. Indeed, in this article we have argued
that a convincing explanation for the flexible objectivism found in experimental research
comes from evolutionary psychology: that some (but not all) moral issues are associated with
a strong sense of objectivity has to do with the psychosocial benefits of objectifying them,
specifically those moral issues that are of personal importance to agents.
Our alternative explanation does not establish that the realist’s metaethical explanation
is false. However, given the good fit our alternative explanation has with findings from
experimental metaethics, and given its evolutionary plausibility, we do think that realists lose
their presumptive entitlement to claim that they have the better explanation. As far as our
argument goes, it is an open question which explanation will ultimately be better – but realists
will have to argue for a claim to superiority. An appeal to the apparent objectivity of moral
experience no longer suffices to think that the starting point of moral realism is more intuitive
than the starting point of antirealist positions. This conclusion may have ramifications for the
success of EDAs against moral realism, insofar as some argue that those EDAs can be resisted
if assumptions about the truth of moral realism are granted.
Interestingly, in the foregoing discussion two different kinds of explanation have been
pitted against each other: the psychological explanation favoured by antirealists, versus
the metaethical explanation favoured by realists. We think that not too much weight should be
attached to these classifications, however: in the present context both of them refer to
descriptive explanations, albeit with different metaphysical postulates. It would be a fallacy to
think that one kind of explanation should be favoured over the other in principle. This fallacy
is reminiscent of the flaw of Ruse’s EDA: as noted in section 1.2, Ruse wrongly assumed that
his evolutionary explanation for the characteristics of our moral phenomenology automatically
renders the metaphysical postulates of realism redundant.
Hence, in explaining the nature of our moral phenomenology, it cannot simply
be assumed that either a psychological or a metaethical explanation will be superior.
Nonetheless, to the extent that these are explanations of the same phenomenon, they may
justifiably be regarded as rivalling explanations. Since this condition is met in the case-study
we have presented, and since moral realists previously assumed to be uniquely able to account
for the objectivist features of moral experience, the psychological findings we have discussed
in this article overturn an important argument in support of moral realism. However, they do
not debunk moral realism as such. Even if an explanandum originally explained in terms of a
realist metaethics is actually better explained in psychological terms, there might still be other
grounds for defending moral realism as the preferred metaethical framework. The burden-of-proof, however, has now shifted to realists to demonstrate this.

6. Conclusion
We presented experimental findings which indicate that there is a positive relation between the
personal importance that subjects attribute to a moral issue and the objectivity they bestow on
this issue. Subsequently, we discussed these findings in the context of the psychosocial and
evolutionary functions of moral objectivity, and proposed that presenting moral demands as
objective may be instrumental to the function of choosing sides in moral debate. This
evolutionary account helps to explain the objectivist phenomenology of moral demands, and
its flexibility depending on different moral issues. The ability to provide such an explanation,
in turn, has implications for the metaethical debate: it serves to undercut the presumptive
assumption of moral realism.

Young people tend to be more liberal than older people; half of the change to conservatism occurs after being 45

Peltzman, Sam, Political Ideology over the Life Course (December 9, 2019). SSRN:

Abstract: Young people tend to be more liberal than older people. This paper goes beyond that generality to describe more precisely how self-described political ideology varies with age. I distinguish period (across people of different ages at a moment in time) from cohort (changes in people as they get older) characterizations of this age-ideology gradient. Data are from General Social Surveys from 1974 through 2018, including synthetic cohorts formed from 5 year subsamples of the data. Ideology is measured on a {-1, 1} scale: liberals (conservatives) are -1 (+1) and moderates are 0. The average of this measure (Libcon) generally increases with age both within every 5-year sub-period and among all available cohorts; the shape of these gradients varies considerably across these sub-periods. However, the longer run central tendency is a very well defined concave gradient that rises over the whole life course. The period and cohort versions of this gradient essentially overlap. The change in mean Libcon from early adulthood (25) to old age (80) is substantial (over. 20 on the -1, 1 scale), and around half of this occurs after age 45. I discuss implications for “purple America” characterizations of political ideology and for the strain of literature emphasizing ideological “persistence.”

Keywords: political ideology, liberal, conservative, age
JEL Classification: D72, D78, Z13