Testosterone and Cortisol, the Secular Trend, and the Decline of Forethought and Individuality in Society and Religion

Below an article by James Michael Howard which I copied in its entirety, because I could only find it as a response to another article and would not want to lose it. All rights go to the original author of course, whom I hope does not mind my copying it here.
James Michael Howard's website can be found here: http://www.anthropogeny.com/

Brief

Individuals of higher testosterone and lower cortisol have a reproductive advantage. These individuals are aggressive, sexy, do not control their impulses easily, have less ability to anticipate consequences and smaller prefrontal lobes, and form into groups. Because of their reproductive advantage the population will change and the characteristics of these individuals will increase accordingly within the population.

Another aspect of too much testosterone is increased vulnerability to infections. High testosterone populations prior to the advent of anti-microbial agents and medical care were at increased risk of infections, and pandemics occurred. These plagues of Europe removed most of the people of high testosterone. The surviving people of lower testosterone produced the intellectual accomplishments known as the "Renaissance." Since the plagues differed in effect and timing in the "East," there was not as large a removal of people of high testosterone; the Renaissance was limited to Europe.

Testosterone and Cortisol, the Secular Trend, and the Decline of Forethought and Individuality in Society and Religion

by James Michael Howard

"It is my hypothesis that civilizations have ascended and declined as a consequence of the degree of development of the prefrontal lobes of the brains of the majority of citizens. Development of the prefrontal lobes is a consequence of growth and development of the individual. A change in growth and development of the individuals of a population over time is a "secular trend." I suggest the secular trend results in increases, followed by reductions, in size and function of the prefrontal lobes of many individuals within a population as the population evolves.

The secular trend is the increase in size and earlier puberty in children. The secular trend in the United States is real and robust and is likely "an acceleration of maturation" (Archives of Pediatric and Adolescent Medicine. 2000; 154: 155). Many think the secular trend results from increased nutrition, especially increased fat in the diet. I suggest the trend results from differential reproduction of types of individuals; increased nutrition, mainly increased calories, simply accelerates the process. Increased nutrition provides a favorable "feed and breed" situation. Increased nutrition increases the advantages of a faster breeding group over a slower breeding group. I think the trend represents the increase in percentage of individuals who produce different levels of hormones that directly, and positively, affect their rate of reproduction. Individuals of higher testosterone and lower cortisol have a reproductive advantage in our society.

Testosterone increases sex drive and aggression in men and women. Given time, individuals of higher testosterone will reproduce faster than those of less testosterone. This trend will increase the percentage of sexier, more aggressive individuals. The population will change and the characteristics of these individuals will increase accordingly within the population.

Cortisol is the "stress hormone." When cortisol increases in response to a stimulus, cortisol reduces the response to that stimulus. Behaviors that stimulate cortisol do not occur often. Women who produce less cortisol engage in sexual intercourse at a younger age and produce less cortisol in response to stress later in life (Psychoneuroendocrinology 2002; 27: 933). Women of low cortisol and high testosterone "may" engage in sexual activity much earlier and with greater frequency than those of higher cortisol and lower testosterone.

Given time, these women and their offspring will increase in percentage within a population and affect the characteristics of that population.
They are sexy and fearless.

Testosterone affects both the brain and body. From birth until puberty, the brain and body compete for growth and development. Early in growth and development, the brain, as a whole, dominates this competition. As the brain begins to finalize its growth, its ability to compete for testosterone begins to decrease compared to the body. At this time, the part of the brain that controls sex drive (lower brain) is complete, but the final part of brain development (upper brain) is not complete. (This competition of brain and body development is how the onset of puberty is delayed until the brain is almost complete.) The part of the brain that controls sex drive contains more "receptors" for testosterone than the upper brain. As puberty approaches, this combination of competition for testosterone from the lower brain and the body adversely affect final development of the upper brain, specially the prefrontal lobes. In an individual of higher testosterone, the increased testosterone positively affects the lower brain during this competition. Puberty occurs early, the final part of growth and development of the prefrontal lobes is adversely affected and, in a person of low cortisol, sexual behavior starts early. The combination of high testosterone and low cortisol increases the use of testosterone for the behavior controlled by the lower brain, that is, puberty and sexual activity. These individuals should exhibit reduced ability to control their behavior because of high testosterone, low cortisol, and reduced development of their prefrontal lobes. Outside of their group, they exhibit impulse control problems.

Individuals of high testosterone and low cortisol present real problems for society. High testosterone is connected with violent, negative behaviors. "The matched analysis further substantiated the association between testosterone secretion and learning disabilities." (Physiol Behav 1993; 53: 583). "The group of rapists who were judged to be most violent had a significantly higher mean plasma testosterone level than normals, child molesters, and other rapists in this study." (Psychosom Med 1976; 38: 257). "In the housing unit where peer ratings were most reliable, inmates rated as tougher by their peers were higher in testosterone." (Psychosom Med 1987 49: 174). "Decreased cortisol levels appear to be most strongly associated with antisocial girls who do not have other psychiatric disorders." (Arch Gen Psychiatry. 2001; 58: 297). "Low cortisol levels were associated with persistence and early onset of aggression, particularly when measures of cortisol concentrations were pooled. Boys with low cortisol concentrations at both time points exhibited triple the number of aggressive symptoms and were named as most aggressive by peers 3 times as often as boys who had higher cortisol concentrations at either sampling time." (Arch Gen Psychiatry 2000; 57: 38). Most importantly to this treatise is the finding that prefrontal gray matter volume is reduced in a group of people who exhibit "antisocial personality disorder (APD)" who otherwise "do not have discernible brain trauma." "The APD group showed an 11.0% reduction in prefrontal gray matter volume in the absence of ostensible brain lesions and reduced autonomic activity during the stressor. These deficits predicted group membership independent of psychosocial risk factors." (Arch Gen Psychiatry 2000; 57: 119). These individuals are aggressive, sexy, do not control their impulses easily, and form into groups.

Mathematics, science, language, and law depend upon real consequences. "Culture" and "religion" depend upon hypothetical consequences. "Forethought," or hypothesis formation, is dependent upon development of the prefrontal lobes of the brain. Hypothesis formation consists of two simple questions: "If this happens, what will happen?" and its immediate accompaniment, "If I do this, what will happen?" I specifically stated that religion utilizes "hypothetical consequences" to enforce the hypothesis: "If I do this, what will happen?" Whether one believes in a God of the present or of the future, the consequences that result from transgressions of doctrine remain abstract. One has to
wonder (hypothesize) when consequences will happen, soon or upon one's death. I have suggested that the prefrontal lobe declines within civilizations. The last quotation of the paragraph, above, I think, supports my hypothesis and adds one very significant finding. The prefrontal lobes of the subjects of the study were actually reduced in size in "antisocial personality disorder." This results in loss of individuality: "These deficits predicted group membership independent of psychosocial risk factors." Reductions in the prefrontal lobes result in loss of ability to anticipate consequences and also increase group membership. This translates to thinking with the lower brain, emotional thinking, and groups of emotional thinkers. Religion relies on some combination of abstract thinking or emotional thinking. The percentages of individuals who utilize either abstract thinking or emotional thinking may produce the different religions and denominations. I suggest some religions rely on emotional thinking because it exerts more control over their flocks. These religions contain groups of individuals of higher testosterone and lower cortisol who may be moved to commit acts that are in direct contrast to the founding religion. Given time, the secular trend will produce this phenomenon. There are other, natural circumstances that may accelerate this phenomenon. Though this occurs in the "West," there are reasons why religions of the "East" contain more "zealot" sects. "Western Civilization" and its religions may differ because of a biological accident.

Again, I think testosterone increases and cortisol decreases in all civilizations. I think the secular trend is a phenomenon of all human populations that have succeeded in producing civilizations. Fortuitously for Europe and the West, another, consequential, negative aspect of too much testosterone is increased vulnerability to infections. Testosterone has been connected with increases in all types of infectious agents.

Experimentally, testosterone has been used to prove this connection. Therefore, populations prior to the advent of anti-microbial agents and medical care were at increased risk of infections. Where infectious agents gained entry into high testosterone populations, pandemics occurred. These plagues of Europe accomplished something "beneficial," that is, the plagues removed most of the people of high testosterone. The surviving people of lower testosterone produced the intellectual accomplishments known as the "Renaissance." Since the plagues differed in effect and timing in the "East," there was not as large a removal of people of high testosterone; the Renaissance was limited to Europe.

"Western civilization" is the result of the "good luck" of having plagues remove the majority of people of high testosterone. Therefore, fewer sects have evolved out of the paramount religions in the West. It is beginning to happen here; there were / are religious atrocities in Western religions, but the atrocities of Eastern religions far surpass those of the West at this time.

*Copyright: 2002, James Michael Howard, Fayetteville, Arkansas, U.S.A. This work is derived from three of my papers: "Hormones in Mammalian Evolution," Rivista di Biologia / Biology Forum 2001; 94: 177-184; "Androgens in Human Evolution. A New Explanation of Human Evolution," Rivista di Biologia / Biology Forum 2001; 94: 345-362, and "Mitochondrial Eve, Y Chromosome Adam,Testosterone, and Human Evolution," Rivista di Biologia / Biology Forum 2002; 95: 319-326.

Competing interests:  None declared

Competing interests: No competing interests"

(source: http://www.bmj.com/rapid-response/2011/10/29/actually-it-more-testosterone)

Autism, Asperger's and prenatal testosterone

Introduction: why autism studies may shed light on the behavior of the general population

People with autism or Asperger's have been found to have a lower 2D:4D digit ratio than average, and to have been exposed to higher amounts of prenatal testosterone:

"We found that the 2D:4D ratios of children with autism, their siblings, fathers and mothers were lower than population normative values. Children with AS, who share the social and communicative symptoms of autism but have normal or even high IQ, had higher 2D:4D ratios than children with autism but lower ratios than population normative values."

(source: The 2nd to 4th digit ratio and autism, J T Manning PhD, S Baron-Cohen PhD, S Wheelwright MA and G Sanders PhD, Version of Record online: 2 MAR 2007, retrieved July 1st 2016)

"[The study result] suggests that [boys with higher levels of fetal testosterone] have a greater proclivity for "approach-related behaviors," such as fun-seeking and impulsivity. [...] For males, such behaviors are often heightened in teenage years and are found in extremes in many psychiatric conditions, such as [...] autism."

(source: Fetal Testosterone May Program Boys' Behavior, By Live Science Staff | November 5, 2012, retrieved 22/07/2016)

"fT (fetal Testosterone) levels were positively associated with higher scores on the CAST (Childhood Autism Spectrum Test) and AQ-Child (Child Autism Spectrum Quotient). This relationship was seen within sex as well as when the sexes were combined, suggesting this is an effect of fT rather than of sex per se. [...] These findings are consistent with the hypothesis that prenatal androgen exposure is related to children exhibiting more autistic traits."

(source: British Journal of Psychology (2009), 100, 1–22, Fetal testosterone and autistic traits, Bonnie Auyeung, Simon Baron-Cohen, Emma Ashwin, Rebecca Knickmeyer, Kevin Taylor, and Gerald Hackett)

"“We previously knew that elevated prenatal testosterone is associated with slower social and language development, better attention to detail, and more autistic traits. Now, for the first time, we have also shown that these steroid hormones are elevated in children clinically diagnosed with autism. [...] These new results are particularly striking because they are found across all the subgroups on the autism spectrum, for the first time uniting those with Asperger Syndrome, classic autism, or Pervasive Developmental Disorder Not-Otherwise-Specified.”"

(source: Elevated ‘Male Hormones’ During Fetal Development Linked With Autism, www.iflscience.com, retrieved 22/07/2016, referring to Molecular Psychiatry (2015) 20, 369–376; doi:10.1038/mp.2014.48; published online 3 June 2014,Elevated fetal steroidogenic activity in autism, S Baron-Cohen et al.)

"The Empathizing–Systemizing (E-S) theory of typical sex differences suggests that individuals may be classified based on empathy and systemizing. An extension of the E-S theory, the Extreme Male Brain (EMB) theory suggests that autistic people on average have a shift towards a more masculinized brain along the E-S dimensions. Both  theories have been investigated in small sample sizes, limiting their generalizability. Here we leverage two large datasets (discovery n = 671,606, including 36,648 autistic individuals primarily; and validation n = 14,354, including 226 autistic individuals) to investigate 10 predictions of the E-S and the EMB theories. In the discovery dataset, typical females on average showed higher scores on short forms of the Empathy Quotient (EQ) and Sensory Perception Quotient (SPQ), and typical males on average showed higher scores on short forms of the Autism Spectrum Quotient (AQ) and Systemizing Quotient (SQ). Typical sex differences in these measures were attenuated in autistic individuals. Analysis of “brain types” revealed that typical females on average were more likely to be Type E (EQ > SQ) or Extreme Type E and that typical males on average were more likely to be Type S (SQ > EQ) or Extreme Type S. In both datasets, autistic individuals, regardless of their reported sex, on average were “masculinized.” Finally, we demonstrate that D-scores (difference between EQ and SQ) account for 19 times more of the variance in autistic traits (43%) than do other demographic variables including sex. Our results provide robust evidence in support of both the E-S and EMB theories."

(Greenberg, David M., Varun Warrier, Carrie Allison, and Simon Baron-Cohen. "Testing the empathizing–systemizing theory of sex differences and the extreme male brain theory of autism in half a million people." Proceedings of the National Academy of Sciences (2018): 201811032.)

(see also Effects of (fetal) testosterone on brain and behavior)

Inversely, the (neurological) study of people with autism may give indications of how prenatal testosterone influences the human brain in general, also in those who have been exposed to levels lower than those found in persons on the autistic spectrum. Autistic people might be on the extreme end of high prenatal testosterone levels, while a significant portion of non-autistic ("neurotypical") people may exhibit traits which tend towards the autistic extremes (eg. low empathy, agression, systemizing versus empathizing, etc), without actually being so extreme, depending on prenatal testosterone levels.

General studies on autism

"Autistic phenotypes have been linked (...) to increased protein synthesis at synapses (Bourgeron, 2009), higher excitatory to inhibitory neurotransmission (Rubenstein and Merzenich, 2003), enhanced local compared to global processing and connectivity (Happé and Frith, 2006), a bias toward systemizing over empathizing (Baron-Cohen, 2009), and enhanced perceptual functioning (Mottron et al., 2006). These patterns and theories are not mutually exclusive (...)."

(Crespi, Bernard J. "Autism As a Disorder of High Intelligence." Frontiers in Neuroscience 10 (2016).)

Tendency of people with autism to partner with others on the spectrum may raise the condition's prevalence

"The tendency of people with autism to partner with others on the spectrum may raise the condition’s prevalence within families and across the population, according to a new study.

Researchers used genetic modeling to estimate the impact of this ‘nonrandom mating’ pattern among individuals with autism. The approach uses equations to deduce how genetic traits move through populations."

"People with autism are up to 11 times more likely than their typical peers to choose a partner on the spectrum."

(Partner preferences may contribute to autism prevalence, Spectrum, December 5 2016)

People with autism have more symmetrical brains

"[I]n typically developing young people, the right brain hemispheres had densely packed connections.

'This fits with the idea that the right hemisphere has a more integrative function, bringing together many kinds of information,' the team wrote in a summary of their research.

However, in the participants with ASD, these brain connections were more evenly distributed across both hemispheres.
[...]

MRI scans revealed that connections between white matter in the brains of young people with autism were more symmetrical across hemispheres. [...]

'The idea behind asymmetry in the brain is that there is a division of labor between the two hemispheres,' Müller said. 'It appears this division of labor is reduced in people with autism spectrum disorder.'

That lack of specialization could manifest itself in what Müller calls 'weak central coherence' — a concept best summed up in the idiom, 'not seeing the forest for the trees.' Many people with ASD are very good at seeing details but have difficulty putting it all together into a cohesive narrative, he explained."

(Brain Connections Show More Symmetry Between Hemispheres in People With Autism,
Neuroscience News, December 1, 2016)

Facial features of boys with autism and Asperger's

"White lines are statistically significantly increased in boys with autism spectrum disorder (ASD), and black lines are statistically significantly reduced in boys with ASD relative to typically developing (TD) boys."

(source: https://molecularautism.biomedcentral.com/articles/10.1186/2040-2392-2-15)



"Frontonasal prominences (FNP) and lateral nasal prominences (LNP) are shown in purple, maxillary prominences (MAX) are shown in blue, mandibular prominences (MAND) are shown in green and second branchial arch derivatives are shown in shades of pink." 

(source: https://molecularautism.biomedcentral.com/articles/10.1186/2040-2392-2-15)

"We found that essential autism in boys is associated with a distinctive facial phenotype characterized by an increased breadth of the mouth, orbits and upper face, combined with a flattened nasal bridge and reduced height of the philtrum [the divot below the nose, above the top lip] and maxillary [upper jawbone] region. [...]
[W]e found a narrowing of the intercanthic distance [distance between the inner corners of the eyes], or mild hypotelorism [distance between the eyes]. These findings are complementary in that we found an overall decrease in intercanthic distance, which potentially translates to decreased interpupillary distance, although we did not directly measure that distance.[...]

(source: Facial phenotypes in subgroups of prepubertal boys with autism spectrum disorders are correlated with clinical phenotypes, Kristina Aldridge e.a., Molecular Autism 2011, retrieved July 2nd 2016)

"Aldridge and colleagues found the following distinct differences between facial characteristics of children with autism and those of typically developing children:
Children with autism have a broader upper face, including wider eyes.
Children with autism have a shorter middle region of the face, including the cheeks and nose.
Children with autism have a broader or wider mouth and philtrum -- the divot below the nose, above the top lip."

(source: Autistic facial characteristics identified, ScienceDaily, october 21 2011, retrieved July 2nd 2016)

More Asperger's in maths, physics, engineering and computer science than in general population

"A recent survey of Cambridge undergraduates confirmed the belief that it is among the students of mathematics, physics, engineering and computer science that Asperger syndrome is most likely to be found."

(James, Ioan. "Singular scientists." Journal of the Royal Society of Medicine 96.1 (2003): 36-39.)

Current standard tests for detecting autism may miss autistic females

"Overall, the findings suggest that some autistic females may be missed by current diagnostic procedures."

(Ratto, Allison B., et al. "What About the Girls? Sex-Based Differences in Autistic Traits and Adaptive Skills." Journal of Autism and Developmental Disorders (2017): 1-14.)

Autistic traits are on a continuum in the wider community, with ASD representing an extreme end

"There is accumulating evidence that autistic traits are on a continuum in the wider community, with ASD representing an extreme end of the distribution."

(Tan, Diana Weiting, Murray T. Maybery, Michael W. Clarke, Renata Di Lorenzo, Melissa O. Evans, Michael Mancinone, Christina Panos, and Andrew JO Whitehouse. "No relationship between autistic traits and salivary testosterone concentrations in men from the general population." PloS one 13, no. 6 (2018): e0198779.)

Symptom severity in autism spectrum disorder is related to the frequency and severity of nausea and vomiting during pregnancy

"Impairments in social responsiveness in offspring, as indexed by SRS total score, significantly increased as a function of the frequency and severity of their mothers’ NVP [Nausea and vomiting during pregnancy], as did the level of language difficulties as indexed by the Global Communication Composite of the CCC-2.
The strong, positive association between increasing frequency and severity of NVP and ASD severity in offspring provides further evidence that exposure to an atypical hormonal environment during prenatal life may affect neurodevelopment and contribute to the ASD phenotype."

(Whitehouse, Andrew JO, Gail A. Alvares, Dominique Cleary, Alexis Harun, Angela Stojanoska, Lauren J. Taylor, Kandice J. Varcin, and Murray Maybery. "Symptom severity in autism spectrum disorder is related to the frequency and severity of nausea and vomiting during pregnancy: a retrospective case-control study." Molecular Autism 9, no. 1 (2018): 37.)

Criticism of the 'extreme male brain' theory as an explanation for autism

"The implication of this critical review of theory is that the concept of ‘the extreme male brain’ as a description or explanation of autism should be abandoned and replaced with the recognition that scores at any point on the AQ can be the product of a brain within either a male of female person. This allows the search for the biological basis, developmental causes and clinical correlates of autism to be broadened beyond that of differences between the sexes."
[...] ‘[E]ssentialism’ is the philosophical position which claims that things have a set of characteristics that makes them what they are. In the current context, essentialism would claim that there is such a thing as ‘maleness’ and that men deviating from this maleness are not truly male, rather than that such variation merely makes maleness more diverse."

(Ridley, Rosalind. "Some difficulties behind the concept of the ‘Extreme male brain’in autism research. A theoretical review." Research in Autism Spectrum Disorders 57 (2019): 19-27.)

Further support for extreme male brain theory concerning autism

"We demonstrated that females and males with ASD tended to follow the male pattern of developmental changes in interhemispheric connectivity, supporting the EMB theory of ASD."

(Kozhemiako, Nataliia, Vasily Vakorin, Adonay S. Nunes, Grace Iarocci, Urs Ribary, and Sam M. Doesburg. "Extreme male developmental trajectories of homotopic brain connectivity in autism." Human Brain Mapping, First published: 11 October 2018.)

High-functioning Autism (Asperger) associated with low 2D:4D in women and high 2D:4D in men

"Abstract
BACKGROUND:
The 'extreme male brain' theory suggests that autism spectrum disorder (ASD) is an extreme variant of male intelligence. However, somewhat paradoxically, many individuals with ASD display androgynous physical features regardless of gender.
AIMS:
To assess physical measures, supposedly related to androgen influence, in adults with and without ASD.
METHOD:
Serum hormone levels, anthropometry, the ratio of 2nd to 4th digit length (2D:4D) and psychiatric symptomatology were measured in 50 adults with high-functioning ASD and age- and gender-matched neurotypical controls. Photographs of face and body, as well as voice recordings, were obtained and assessed with respect to gender coherence, blindly and independently, by eight assessors.
RESULTS:
Women with ASD had higher total and bioactive testosterone levels, less feminine facial features and a larger head circumference than female controls. Men in the ASD group were assessed as having less masculine body characteristics and voice quality, and displayed higher (i.e. less masculine) 2D:4D ratios, but similar testosterone levels to controls. Androgynous facial features correlated strongly and positively with autistic traits measured with the Autism-Spectrum Quotient in the total sample. In males and females with ASD dehydroepiandrosterone sulfate did not decrease with age, in contrast to the control group.
CONCLUSIONS:
Women with ASD had elevated testosterone levels and several masculinised characteristics compared with controls, whereas men with ASD displayed several feminised characteristics. Our findings suggest that ASD, rather than being characterised by masculinisation in both genders, may constitute a gender defiant disorder."

(Bejerot, Susanne, Jonna M. Eriksson, Sabina Bonde, Kjell Carlström, Mats B. Humble, and Elias Eriksson. "The extreme male brain revisited: gender coherence in adults with autism spectrum disorder." The British Journal of Psychiatry 201, no. 2 (2012): 116-123.)

Many different neurological characteristics underly a common diagnosis of ASD

"Growing evidence shows that neural bases of ASDs cannot be pinpointed to specific regions of the brain, but that symptomatology is instead linked to atypical connectivity within and between functionally specialized brain networks (including ‘social brain’ networks). However, few neuroimaging findings have been widely replicated and no clear picture of the brain bases of sociocommunicative impairments in ASDs has emerged.
A main factor that has prevented consensus findings is etiological diversity. While diagnostic criteria focus on social deficits in ASDs, these probably result from the convergence of many different neurodevelopmental trajectories and many different causative factors."

(Müller, Ralph-Axel, and Inna Fishman. "Brain Connectivity and Neuroimaging of Social Networks in Autism." Trends in Cognitive Sciences (2018).)

Autism and neurological "rigidity"

"What does autism look like in the brain?A new study offers a fresh perspective on how autism works in the brain. Symptoms, the authors say, may be linked to persistent connections in the brain."

(What does autism look like in the brain?, Medical News Today, Published Tuesday 20 November 2018 By Maria Cohut, Fact checked by Paula Field)

Autism signs in ears and mouth form

"[M]inor malformations of the external ears -- notably posterior rotation, in which the top of the ear is tilted backward more than 15 degrees, are more common in children with autism than in typically developing children, children with mental retardation or siblings of children with autism. (...)
Child with autism is normal in appearance, at least to the untrained eye. But he has a few physical anomalies characteristic of the disorder. The corners of his mouth are low compared with the center of his upper lip, and the tops of his ears flop over (left). His ears are a bit lower than normal and have an almost square shape (right)."

(The Early Origins of Autism by Patricia M. Rodier, originally published in "Scientific American," February 2000)

Low fetal cortisol associated with ASD

"Fetal exposure to lower levels of maternal cortisol was associated with higher levels of ASD symptoms only among boys. The observed hypocortisolemic profile exhibited by these mothers may indicate a risk factor that precedes the stress of caregiving for a child with ASD and may not be solely a consequence of the stress of caregiving, as previously thought. These findings confirm the value of examining prenatal hormone exposures as predictors of ASD risk and support the premise that altered prenatal steroid exposures may play a role in the etiology of ASD."

(Ram, Sheena, Mariann A. Howland, Curt A. Sandman, Elysia Poggi Davis, and Laura M. Glynn. "Prenatal Risk for ASD: Fetal Cortisol Exposure Predicts Child Autism-Spectrum-Disorder Symptoms." Clinical Psychological Science (2018): 2167702618811079.)

39% more girls have Autism Spectrum Disorder than currently diagnosed

"The current study estimates that approximately 39 percent more girls should be diagnosed with ASD."

(Barnard-Brak, Lucy, David Richman, and M. Hasan Almekdash. "How many girls are we missing in ASD? An examination from a clinic-and community-based sample." Advances in Autism (2019).)

People with ASD have higher non-verbal than verbal skills; using abbreviated IQ-tests may misrepresent IQ

"The Fifth Edition of the Stanford-Binet Intelligence Scales (SB5; Roid, G. H. (2003). Stanford Binet intelligence scales (5th ed.). Itasca, IL: Riverside Publishing) is relatively new, with minimal published research on general populations and none with special populations. The present study provides information on the cognitive profiles of children with ASD (N=63) and on the whether the abbreviated battery is representative of the full scale. A high percentage of the children had significantly stronger nonverbal (vs. verbal) skills. This pattern was not related to Full Scale IQ, age or diagnostic subgroup. IQs derived from the abbreviated battery accounted for a large proportion of the variance in FSIQ relative to comparable abbreviated batteries. However, caution is warranted when using the abbreviated battery, as it misrepresents actual ability in a small percentage of cases."

(Coolican, Jamesie, Susan E. Bryson, and Lonnie Zwaigenbaum. "Brief report: Data on the Stanford–Binet intelligence scales in children with autism spectrum disorder." Journal of Autism and Developmental Disorders 38.1 (2008): 190-197.)

Genetics and their influence on behavior, brain and society

All individual psychological differences are moderately to substantially heritable

"Psychological researchers typically distinguish five major domains of individual differences in human behavior: cognitive abilities, personality, social attitudes, psychological interests, and psychopathology. [...] In this article we [...] review behavioral genetic findings in all five domains. We conclude that there is now strong evidence that virtually all individual psychological differences, when reliably measured, are moderately to substantially heritable."

(Bouchard, Thomas J., and Matt McGue. "Genetic and environmental influences on human psychological differences." Journal of neurobiology 54.1 (2003): 4-45.)

DNA defines number of androgen receptors in brain

"Many factors influence how androgens impact brain functioning. Of course, some of these factors involve the actual prevalence of androgens in the brain during crucial periods of development (Kimura, 1992; Nordeen, Nordeen, Sengelaub, & Arnold, 1985). Another factor involves so-called androgen receptors (ARs). Without these receptors, the prevalence of androgens is largely inconsequential (La Spada, Wilson, Lubahn, Harding, & Fischbeck, 1991; Sato et al., 2004). The number of ARs is in turn determined by what are known as CAG repeats in the androgen receptor (AR) gene (located on the X chromosome, of which males only have one). The more CAG repeats on the X chromosome, the fewer the number of ARs an individual will have (Allen, Zoghbi, Moseley, Rosenblatt, & Belmont, 1992; Giovannucci et al., 1997). The number of CAG repeats in the AR determining gene is likely to play an important role in the ability of androgens to influence criminality and related behaviors (such as psychopathy).
Recent evidence pertaining to the above reasoning has been encouraging. A study conducted in India involving over five hundred men, roughly half of whom were convicted of rape. Evidence from
this study revealed that the rapists had significantly shorter CAG repeats in their AR genes than control males (Rajender et al., 2008). Also, a Chinese study found that the length of the AR gene repeats was significantly shorter among violent criminals than among the non-criminal males (Cheng, Hong, Liao, & Tsai, 2006). Findings from both of these reports suggest that male criminals, particularly those with assaultive tendencies, have unusually short CAG repeats in their AR genes relative to males in general. Furthermore, research has shown that the number of CAG repeats in AR genes is inversely associated with childhood conduct disorders and other forms of externalizing behavior among boys (Aluja, García, Blanch, & Fibla, 2011; Comings, Chen, Wu, & Muhleman, 1999)."

(Ellis, Lee, and Anthony W. Hoskin. "The evolutionary neuroandrogenic theory of criminal behavior expanded." Aggression and violent behavior 24 (2015): 61-74.)

HOX genes and influence on gonad, fingers and digit ratios

"The differentiation of gonads, fingers, and toes is influenced by HOXA and HOXD genes. Therefore variation in the development of the gonads, and their fetal products such as testosterone, may be reflected in the morphology of the fingers and toes. One trait, the relative length of the second and fourth digits (2D:4D), shows sex differences (lower values in males) which are determined early, and 2D:4D has been found to correlate with fetal growth, sperm counts, family size, autism, myocardial infarction, and breast cancer. HOX genes are highly conserved in mammals and they influence the differentiation of all the fingers and toes. We suggest that (a) 2D:4D and other ratios of finger and toe length show sex differences throughout the mammals including humans and mice, (b) finger and toe ratios correlate with sex determination, the fetal production of sex steroids, and fetal programming of disease, and (c) HOX gene influences on sex determination, the morphogenesis of the urinogenital system, fertility, haematopoiesis, and breast cancer suggests that finger and toe ratios in humans and mice may correlate with many sex dependent diseases."

(Manning, J. T., M. Callow, and P. E. Bundred. "Finger and toe ratios in humans and mice: implications for the aetiology of diseases influenced by HOX genes." Medical Hypotheses 60.3 (2003): 340-343.)

"[I]n 1984 the psychologist Sarnoff Mednick tapped into a Danish database of more than 14,000 adopted children, some of whom had been convicted of crimes. Mednick found that more than twice as many offenders convicted of property crimes, such as breaking and entering, had a biological father who was a criminal, compared with those who had an adopted criminal father; the proportion was even higher for repeat offenders. He concluded that criminal parents passed on ‘some factor’ to their biological children that made it likelier for them to become criminals, but noted that the correlation did not hold true when looking at violent crimes such as murder or assault.
Others have studied twins to look for hereditary similarities. Scientists who have analysed Denmark’s twin records have found a stronger correlation in crime between identical twins than between non-identical ones. That’s not to say that born criminals exist, according to Irving Gottesman, a psychologist at the University of Virginia who studied the Danish twin records; but heredity seemed to play a role in setting up the odds.[...]
[I]n 2011 [Avshalom Caspi and Terrie Moffitt of Duke University in North Carolina] published a finding (one among the hundreds they have produced over the years) that psychological assessments of self-control in children as young as three can predict whether a child will become a criminal in his or her 30s. They were able to reach that conclusion only after compiling the data of more than 1,000 people who had been tracked from early childhood to adulthood.[...]
While one gene does not equal one behaviour, for instance, patterns in thousands of genes can interact with thousands of behaviours in a constantly changing human environment. One study of fruit flies bred for aggression found partial links to 80 different genes. It’s also become known that gene expression is not a one-way street: while genes might affect a person’s body or even behaviour, the person’s environment can affect genetic expression. In one of their studies undertaken in Dunedin, Moffit and her post-doctoral student Idan Shalev found that 10-year-olds who experienced violence showed the kind of wear and tear in their DNA normally associated with ageing. All this means that, while it’s possible that a particular gene deficiency might have something to do with violent behaviour, it’s ludicrous to say that it directly caused it.
The same is true of brain structure and function. In recent years, researchers have learned that just as the brain can set tendencies, experiences can influence how they’re expressed.[...]
Minus the clutter, if you look at the totality of peer-reviewed studies of the past several years, it’s hard not to come to the conclusion that biology plays some role in criminal behaviour, impossible to quantify. The new science of epigenetics proposes an interaction between environment and heredity, in which environmental factors (such as childhood abuse) can affect the expression of genes. In other words, the nature-nurture division that scientists have been arguing about for more than a century is narrowing, and might someday disappear. Genes and brain structure do not represent a simple on-off switch that determines a person’s behaviour but, as some studies show, they can indicate a vulnerability.[...]
[Adrian Raine, professor of psychology, psychiatry and criminology at the University of Pennsylvania] has been studying brain scans for decades, and he has come up with a kind of grand unified theory of violence. He describes it with the phrase ‘from genes to brain to antisocial behaviour’. Certain gene abnormalities can lead to structural brain abnormalities that lead to emotional and cognitive abnormalities (such as poor impulse control) that can lead to anti-social behaviour. At the same time, he writes, early life experiences – including maternal neglect, poor nutrition, or being surrounded by gang violence – can feed into the cycle."

(source: "The inheritance of crime", by Douglas Starr, professor of journalism at Boston University, where he is co-director of the Center for Science and Medical Journalism. published on Aeon, retrieved 26-7-2016)

"Your genes may influence how sensitive you are to emotional information, according to new research by a UBC neuroscientist. [...] The gene in question is ADRA2b, which influences the neurotransmitter norepinephrine. [...] "We thought, from our previous research, that people with the deletion variant would probably show this emotionally enhanced vividness, and they did more than we would even have predicted, [...]."

(source: How your brain reacts to emotional information is influenced by your genes)

"Scientists have confirmed that variations in [the GABRB3] gene [... are] linked to differences in empathy levels in the general population."

(source: Study confirms a gene linked to Asperger Syndrome and empathy)

"Intellectual faculties are the sum of many factors, the majority of which are genetic and inherited from parents." (Dr. Sébastien Jacquemont, geneticist, clinical researcher at CHU Sainte-Justine and professor at the University of Montreal)

(source: Twenty-five-point drop in IQ caused by lack of gene copy, accessed 2016-01-28)

"In this study, the Japanese researchers determined that ​PX-RICS is most likely the gene responsible for autism-like symptoms in Jacobsen syndrome. To do this, they performed several well-established tests that measure common autism symptoms -- anti-social behavior, repetitive activities and inflexible adherence to routines. As compared to normal mice, mice lacking PX-RICS spent less time on social activities (e.g., nose-to-nose sniffing and huddling) and were more apathetic or avoidant when approached by a stimulator mouse. PX-RICS-deficient mice also spent more than twice as much time on repetitive behaviors such as self-grooming and digging than normal mice. In addition, mice lacking PX-RICS more closely adhered to a previously established habit and were less able to adapt their behavior in novel situations."

(Mouse model yields possible treatment for autism-like symptoms in rare disease, Sciencedaily, retrieved 17-3-2016)

"We were surprised by certain behaviors that showed a genetic influence, such as religiosity [and] social attitudes," said Nancy Segal, an evolutionary psychologist at California State University, Fullerton, who was part of the study for nine years. "Those surprised us, because we thought those certainly must come from the family [environment]," Segal told Live Science. [...]
The Minnesota researchers found that about 70 percent of IQ variation across the twin population was due to genetic differences among people, and 30 percent was due to environmental differences. The finding received both praise and criticism, but an updated study in 2009 containing new sets of twins found a similar correlation between genetics and IQ.
Moreover, a study in 1990 found that genetics account for 50 percent of the religiosity among the population — in other words, both identical twins raised apart were more likely to be religious or to be not religious, compared with unrelated individuals."

(Source: LiveScience, retrieved 30-5-2016)

(source: "Insights From Identical Twins", http://learn.genetics.utah.edu/content/epigenetics/twins/, retrieved 30-5-2016)

Nature or Nurture? The Study of Twins | Nancy Segal and Stefan Molyneux

"[T]hey looked at the IQ scores of mothers who had given away their children for adoption. So they had the IQ score of the biological mom, the adopted away kid, and the adoptive parents of that kid. And you know who was more alike? The biological kid and the biological mom who were not together, as compared to the adoptive mom who had raised the adoptive child."

(Dr. Nancy L. Segal, B.A. degree in psychology (with distinction) and English literature from Boston University (1973), and M.A. (1974) and Ph.D. (1982) degrees in Social Sciences and Behavioral Sciences from the University of Chicago. She is currently Professor of Psychology at California State University, Fullerton (CSUF) and Director of the Twin Studies Center which she founded in 1991.)
(source: Youtube interview "Nature or Nurture? The Study of Twins | Nancy Segal and Stefan Molyneux", 36min18s)

More arborized cortical neurons (with more dentritic branches) make friendlier, more social brains

"Scientists investigated Williams syndrome or WS, a rare genetic condition caused by deletion of one copy of 25 contiguous genes on chromosome 7, out of an estimated 30,000 genes in the brain. [...] WS results in a host of medical problems as well as a specific heart defect. [...] Neurologically, [persons with the deletion] have developmental delays, with severe spatial deficits, yet relative strengths in language use and face processing.
'An interesting aspect is the typical hyper-social predisposition,' said study co-author Ursula Bellugi, EdD, director of the cognitive neuroscience lab at Salk and an adjunct professor at UC San Diego who has studied WS for years. 'Persons with the WS deletion tend to be overly friendly, overly trusting, drawn to strangers, yet anxious.' [...]
'I was fascinated on how a genetic defect, a tiny deletion in one of our chromosomes, could make us friendlier, more empathetic and more able to embrace our differences,' [co-senior study author Alysson] Muotri [PhD, associate professor of pediatrics and cellular and molecular medicine at UC San Diego School of Medicine], said. [...]
Cultured WS neurons have a distinct morphology. They are more arborized (treelike, with many dendritic branches) than neurons derived from typically developing individuals. "At the functional level, they make more synapses or connections to other neurons than what you would expect," said Muotri. "That might underlie the WS super-social aspect and their gregarious human brain, giving insights into autism and other disorders that affect the social brain." [...]
'One striking observation was that [the] cortical neurons in WS individuals are more complex than controls (typically developing children of same age). The morphological alterations that presumably appeared during WS gestation are kept postnatally,' [said Katerina Semendeferi, PhD, co-senior author and professor at UC San Diego Department of Anthropology.]"

(source: "Neurodevelopmental model of Williams syndrome offers insight into human social brain", SienceDaily, August 10 2016)

General neuroscience

Cognitive empathy can be learned, but erodes without continuous reinforcement

"Cognitive empathy can be learned [...] but the bad news is that it needs continuous reinforcement."

(Cundell, Diana R. "Culturing the Empathic Health Professional: Challenges and Opportunities." Healthcare Transformation 2.2 (2017): 71-83.)

Neurofeminism

"However, the outcome of research on differences between women and men in terms of linguistic abilities, spatial orientation, or mathematics—that is, of cognitive capacities in general—is by no means conclusive (Schmitz, 1999; Coluccia and Louse, 2004; Spelke, 2005; Mehl et al., 2007; Else-Quest et al., 2010; Lavenex and Lavenex, 2010; Fausto-Sterling et al., 2012a,b); neither are results on emotional or rational processing (Karafyllis, 2008) (...).

(...)

Feminist neuroscientists have uncovered inconsistent findings concerning sex differences and elaborated similarities between or variations within the gender groups, not only on the level of behavior and performance but also concerning their apparently biological sources, i.e., the brain networks and their functions (Frost et al., 1999; Blanch et al., 2004; Ulshöfer, 2008; Wallentin, 2009; Jordan-Young, 2010; Bluhm et al., 2012; Jordan-Young and Rumiati, 2012; Kuria, 2012; Roy, 2012; Vidal, 2012; Dussauge, 2014; Kaiser, 2014; Sommer et al., 2004, 2008).

(...)

 The concept of brain plasticity points out that brain structures and brain functions are not in any shape or form determined by evolution or remain unchanged during a life span. At birth, the brain is not at all branded or defined, and this network of nerve cells, neuronal fibers and their synapses is not ‘completely formed’ by genetic information.

(...)

The brain plasticity concept is important for deconstructing unilinear statements about a supposedly biological determination of behavior, attitudes, etc. In narrating plasticity stories, neurofeminist scholars mainly stress a return of genealogies of cause and effect, arguing that gendered social experiences and power relations impact the forming of the gendered brain’s structure and function more than vice versa (e.g., Vidal, 2012).

(...)

Modern neurodeterminism does not care whether brain structures and functions are innate or formed by experience, considering it to be irrelevant whether the individual brain is formed by nature or nurture.

(...)

There is an interesting ambivalence that is not articulated in current neurocultural discourse: while plasticity concepts are included in modern neurodeterminism up to the moment of measuring, they are dropped again when it comes to predicting future behavior. Although insisting on the forming of biological materiality from ‘outside’, neurocultural discourse is in danger of remaining connected to concepts that presume to predict behavior, thinking, and acting due to biological entities from ‘inside’. The impacts of these normative framings on cultural understandings, social practices, and governmental discourses are already the subject of critical analyses (Choudhury et al., 2009; Choudhury and Slaby, 2011). Neurofeminism must question the gender-based and intersected legitimations that are drawn from neurocultural discourse and practices, in particular because neuroscientific knowledge production can be used for various socio-political in- and exclusions (O’Connell, 2014).

(...)

One example of a critical examination of neurocultures is Höppner and Schmitz (2014) analysis which pursues the question of how the phenomenon of neuropharmacological enhancement is discussed in the German media. The analysis of 21 public media articles (published between 2006 and 2011 in four German online journals) shows that self-optimization of the brain with the help of neuropharmaceuticals is increasingly predicted as a universal strategy for success. Whereas success-oriented males tend to aim for the improvement of their rational skills, success-oriented-women should focus on regulating their self-confidence. Moreover, the articles once again manifest a hierarchized status quo of rational skills over emotional capacities and a different proficiency level that neuro-enhanced subjects could achieve depending on their gender. While women would need a continual consumption of neuro-enhancers in order to achieve a proficiency level similar to male capacities for a limited time, men should take neuro-enhancers only once a while to selectively enhance their supposedly high capacities (a result of their biological setup) to become the best within the group of the best men.

(...)

Since gendered conceptions and connotations shape individual actions, social practices, and social segregation, gender-sensitive analyses can help to assess the entanglements within and the outcomes of neuro-pedagogies in medial discourse, schools, and universities. More precisely, such approaches outline the interdependencies of bodily materiality, social experiences, and cultural norms by underpinning the alterability and interdependencies of brains, behavior, thinking, and acting throughout a person’s lifetime. In doing so, they suggest alternative concepts and settings for individual learning processes (e.g., Vidal, 2012; Just, 2014; Mead Vetter, 2014)."

(http://journal.frontiersin.org/article/10.3389/fnhum.2014.00546/full)

The brain does not work like a computer 

"No matter how hard they try, brain scientists and cognitive psychologists will never find a copy of Beethoven’s 5th Symphony in the brain – or copies of words, pictures, grammatical rules or any other kinds of environmental stimuli. The human brain isn’t really empty, of course. But it does not contain most of the things people think it does – not even simple things such as ‘memories’.[...]
We don’t store words or the rules that tell us how to manipulate them. We don’t create representations of visual stimuli, store them in a short-term memory buffer, and then transfer the representation into a long-term memory device. We don’t retrieve information or images or words from memory registers. Computers do all of these things, but organisms do not. [...]
A wealth of brain studies tells us, in fact, that multiple and sometimes large areas of the brain are often involved in even the most mundane memory tasks. When strong emotions are involved, millions of neurons can become more active.[...]
Misleading headlines notwithstanding, no one really has the slightest idea how the brain changes after we have learned to sing a song or recite a poem. But neither the song nor the poem has been ‘stored’ in it. The brain has simply changed in an orderly way that now allows us to sing the song or recite the poem under certain conditions. When called on to perform, neither the song nor the poem is in any sense ‘retrieved’ from anywhere in the brain, any more than my finger movements are ‘retrieved’ when I tap my finger on my desk. We simply sing or recite – no retrieval necessary. [...]
For any given experience, orderly change could involve a thousand neurons, a million neurons or even the entire brain, with the pattern of change different in every brain."

(source: "The Empty Brain", by Robert Epstein, senior research psychologist at the American Institute for Behavioral Research and Technology in California, published on Aeon, retrieved 26-7-2016)

Imagine a high fetal testosterone, low 2D:4D ratio brain, which in our hypothesis is highly rigid, interacting with the world. If change would just imply adapting a few data or algorithms, as the to-be-abandoned "the brain is like a computer"-model states, it would be able to handle this. But an extensive change throughout the whole brain, as a more realistic brain model implies, will be outright impossible or at least a painful experience. Maybe easier for such a brain to not adapt to the world, but adapt the world to itself - which at the surface corresponds with dogmatism and radicalism, and the kind of dictatorship we know of low 2D:4D ratio leaders like Mao and Stalin?

Do newborn babies imitate adults? New study says 'no', rekindling long-standing debate

"Professor Slaughter and her colleagues tested infant responses to a wide range of adult gestures at one, three, six and nine weeks of age. (...) 'To our surprise we did not find any evidence that babies imitated any of the gestures at any of the time points,' Professor Slaughter said."

​(source: abc.net.au, retrieved 17-5-2016)

Free will

"Using newer fMRI technology, Soon et al (2008) used a learning algorithm to predict "free will" decisions from brain activity about 7 seconds (and up to 10 seconds) prior to the subject reporting awareness of having made the decision. This experiment has been replicated in other labs: Presenter Marcus du Satoy undergoes it for the BBC documentary The Secret You (2009/2010), and remarks that there is something creepy about the radiologist being aware of his decision several seconds before even he is."

source: Predictive Experiments on Neuroscience of Free Will_, retrieved 18-5-2016)

Perception is constructed by the unconscious mind, then handed to consiousness

"But research shows that every perception we have is actually constructed by the unconscious mind, which then instantly hands it to consciousness. What the unconscious mind uses to do this constructing is largely sensory stimulations. We grasp this information with our senses, we process it with our brains unconsciously, and the product enters our consciousness."

("Spiritual emergency", adjunct professor psychiatrist James Carpenter, in Aeon, retrieved 11/8/2016)

Nucleus basalis, acetylcholine and new connections in the brain

"Our hunch that it’s easier to learn when you’re young isn’t completely wrong, or at least it has a real basis in neurology. However, the pessimistic assumption that learning somehow ‘stops’ when you leave school or university or hit thirty is at odds with the evidence. It appears that a great deal depends on the nucleus basalis, located in the basal forebrain. Among other things, this bit of the brain produces significant amounts of acetylcholine, a neurotransmitter that regulates the rate at which new connections are made between brain cells. This in turn dictates how readily we form memories of various kinds, and how strongly we retain them. When the nucleus basalisis ‘switched on’, acetylcholine flows and new connections occur. When it is switched off, we make far fewer new connections.
Between birth and the age of ten or eleven, the nucleus basalisis is permanently ‘switched on’. It contains an abundance of the neurotransmitter acetylcholine, and this means new connections are being made all the time. Typically this means that a child will be learning almost all the time — if they see or hear something once they remember it. But as we progress towards the later teenage years the brain becomes more selective. From research into the way stroke victims recover lost skills it has been observed that the nucleus basalis only switches on when one of three conditions occur: a novel situation, a shock, or intense focus, maintained through repetition or continuous application."

(Source: "Master of many trades", Robert Twigger, Aeon, 2016)

Ways to study intuitive (automatic, unintentional) empathy without relying on self-reports

"[W]e define intentional empathy as experience sharing that is consistent with a target person’s (i.e., the empathizer’s) focal intention, whatever that may be. By contrast, we conceptually define unintentional empathy as experience sharing that is inconsistent with a target person’s focal intention. Drawing upon conceptual analysis of intentionality within social cognition (Moors & De Houwer, 2006), we distinguish between weak and strong forms of unintentionality. Whereas weak unintentionality describes a process that starts spontaneously without any intention, here, we focus on a strong form of unintentional empathy: empathy that occurs despite intentions to the contrary. To date, no research has defined unintentional empathy with this conceptual precision nor examined unintentional empathy in this strong form.
[...]
To examine the distinction between intentional and unintentional empathy, we use implicit measurement and multinomial modeling. Implicit measures capture spontaneous evaluations while bypassing self-report (for review, see Wentura & Degner, 2010) and are useful for studying empathy, particularly given that people may be motivated to report being highly empathic (Paulhus & Reid, 1991).
[...]
To understand variation in empathy for pain, we created a new sequential priming task: the pain identification task (PIT). This task is modeled on similar sequential priming tasks used in social cognition research, such as the weapon identification task (Payne, 2001). Participants view successive prime and target images, each of which depicts experiences that are painful (i.e., hand pierced with needle) or non-painful (i.e., hand brushed with Q-tip). The task uses well-validated stimuli that people clearly judge as painful or non-painful (Lamm et al., 2007, 2010; Perry et al., 2010). Participants’ focal task is to judge the target experience as painful or non-painful while avoiding any influence of the primes (cf. Payne, 2001); responses are coded for accuracy. Thus, participants’ intentions are set in direct opposition to the influence of the primes."

(Cameron, C. Daryl, Victoria L. Spring, and Andrew R. Todd. "The empathy impulse: A multinomial model of intentional and unintentional empathy for pain." Emotion 17.3 (2017): 395.)

Neural synchronization between individuals

"Indeed, speaker–listener neural synchronization is associated with successful comprehension of a verbal message [...].
(...)
Finally, we assessed whether a self-reported tendency for empathy, that is, the disposition to catch others’ emotional states, would be associated with intersubject synchronization of brain activity. [Our findings suggest (...)] that activity within [the posterior middle temporal gyrus region] was most similar in participants who considered themselves as highly empathetic.
(...)
Catching emotions that other humans express—here in dynamic scenes resembling everyday life—is associated with intersubject synchronization of brain circuitries related to emotional, attentional, and mentalizing processes."

(Nummenmaa, Lauri, et al. "Emotions promote social interaction by synchronizing brain activity across individuals." Proceedings of the National Academy of Sciences 109.24 (2012): 9599-9604.)

"Brain-to-brain synchrony also reflected how much students liked the teacher and how much they liked each other."

(When Students Pay Attention in Class, Their Brains Are in Sync, Neuroscience News, Apr 27, 2017)

The psychopath's brain

"Many psychopaths show a distinctive pattern of brain activity, according to James Fallon, a UC Irvine School of Medicine neuroscientist who accidentally found out he may be one himself.
(...)
Here's a scan of a normal brain (top) and Fallon's brain (bottom). Notice that the normal scan shows much more activity (yellow and red) in the lower frontal lobe than Fallon's (mostly blue).

James Fallon

The scans showed reduced activity in an area towards the center of the brain called the orbital cortex thought to play a role in regulating our emotions and impulses as well as morality and aggression.

Here's a set of brain scans of Fallon's family members. Again, you can see that Fallon's brain has large gaps in activity (black sections) in areas where his wife and children show normal (yellow and green) activity."

James Fallon
(Here's what a psychopath's brain looks like, Business Insider UK, jul.22, 2015)

"Scientists who scanned the brains of men convicted of murder, rape and violent assaults have found the strongest evidence yet that psychopaths have structural abnormalities in their brains. (...) 

The results showed that the psychopaths' brains had significantly less grey matter in the anterior rostral prefrontal cortex and temporal poles than the brains of the non-psychopathic offenders and non-offenders. 

These areas of the brain are important for understanding other people's emotions and intentions, and are activated when people think about moral behavior, the researchers said. 

Damage to these areas is linked with a lack of empathy, a poor response to fear and distress and a lack of self-conscious emotions such as guilt or embarrassment. 

Lindsay Thomson, a professor of forensic psychiatry at the University of Edinburgh who was not involved in this study, said Blackwood's findings add to evidence that psychopathy is a distinct neurodevelopmental brain disorder. Research shows that most violent crimes are committed by a small group of persistent male offenders with ASPD." (Anti-Social Personality Disorder)

(Study finds psychopaths have distinct brain structure, Reuters.com, may 7, 2012)

Neuromarketing adopts approach where behavior is rooted in genes and phsyiological processes

"Researchers of this approach consider our behaviors to be results of psychological processes embodied physiologically in the brain and nervous system. Thus, the biological influences may be rooted in our genes and shape the activities in our brain, and thus behaviors through actions on hormones and neurotransmitters. In this paradigm, our genotypes may be interpreted as a measure of individual differences, while brain activities may be observed and taken as more direct measures of the underlying psychological process."

(Chark R. (2018) Neuromarketing. In: Moutinho L., Sokele M. (eds) Innovative Research Methodologies in Management. Palgrave Macmillan, Cham)

Prenatal maternal anger stress causes neurobiological changes in offspring (with enhanced aggressive behaviors, reduced anxiety)

"Anger stressed maternal rats showed a significant increase in locomotion and aggression but a reduction in sucrose preference. Offspring subjected to pre-gestational anger stress displayed enhanced aggressive behaviors, reduced anxiety, and sucrose preference. Further, offspring subjected to pre-gestational stress showed significant impairments in the recognition index (RI) on the object recognition test and the number of platform crossings in the Morris water maze test. The monoaminergic system was significantly altered in pre-gestationally stressed offspring, and the expression of phosphorylated cyclic adenosine monophosphate response element binding protein (P-CREB), brain-derived neurotrophic factor (BDNF), and serotonin transporter (SERT) levels in pre-gestational stressed offspring were altered in some brain regions. (...) These findings suggest that anger stress before pregnancy could induce aggressive behaviors, cognitive deficits, and neurobiological alterations in offspring."

(Wei, Sheng, et al. "Impact of anger emotional stress before pregnancy on adult male offspring." Oncotarget 8.58 (2017): 98837.)

"Friends" are people with similar neural activity

"The researchers found that you can predict who people are friends with just by looking at how their brains respond to video clips. Friends had the most similar neural activity patterns, followed by friends-of-friends who, in turn, had more similar neural activity than people three degrees removed (friends-of-friends-of-friends).
(...)
The findings revealed that neural response similarity was strongest among friends, and this pattern appeared to manifest across brain regions involved in emotional responding, directing one's attention and high-level reasoning. Even when the researchers controlled for variables, including left-handed- or right-handedness, age, gender, ethnicity, and nationality, the similarity in neural activity among friends was still evident. The team also found that fMRI response similarities could be used to predict not only if a pair were friends but also the social distance between the two."

(Dartmouth College. "Your brain reveals who your friends are: Study illustrates how similar neural responses predict friendships." ScienceDaily. ScienceDaily, 30 January 2018.
Study: Carolyn Parkinson, Adam M. Kleinbaum, Thalia Wheatley. Similar neural responses predict friendship. Nature Communications, 2018; 9 (1) DOI: 10.1038/s41467-017-02722-7)

Meditation does not significantly augment people's compassion or social connectedness, nor does it lower prejudice or agression

"Initial analysis indicated that meditation did have an overall positive impact. The researchers said meditation made people feel moderately more compassionate or empathic, compared to if they had done no other new emotionally-engaging activity.
However further analysis revealed that it played no significant role in reducing aggression or prejudice or improving how socially-connected someone was. The most unexpected result of this study, though, was that the more positive results found for compassion had important methodological flaws -- compassion levels in some studies only increased if the meditation teacher was also an author of the published report.
Overall, these results suggest that the moderate improvements reported by psychologists in previous studies may be the result of methodological weaknesses and biases, said the researchers."

(Coventry University. "Meditation has limited role in making you a better person, says study: For decades many people have claimed meditation can change how we behave towards others and make us more compassionate -- but new research suggests this is not the case.." ScienceDaily. ScienceDaily, 5 February 2018. )

‘Left-cradling bias’ linked to better social cognitive abilities in children

"Children who cradle dolls on the left show higher social cognitive abilities than those who do not, according to new research from City, University of London.
(...)
The study builds on previous knowledge of a 'left-cradling bias' -- the phenomenon that humans will typically cradle a baby on their left side, enabling both parent and child to keep the other in their left visual field -- which is unrelated to dominance of the use of right or left hand. Information from the left visual field is processed by the right hemisphere of the brain, which is associated with emotion and the perception of facial expression.
(...)
[Children] who showed this bias had a significantly higher social ability score compared with those who held the doll on the right."

(City, University of London. "‘Left-cradling bias’ linked to better social cognitive abilities in children." ScienceDaily. ScienceDaily, 9 July 2018. )

Masculine / feminine morphology (not directly correlated with prenatal testosterone)

Morphological traits that are either masculine (ie. present in most biological males) or feminine (ie. present in most biological females) may or may not be correlated to prenatal testosterone.
Here follows a list of morpholoical traits that are easily visible with the naked eye, and that are considered sexually dimorphic. Some of these differences may actually not correlate with the biological sex, but with the "brain sex" (prenatal testosterone levels), ie. the masculine/feminine brain as described in Prof. Baron-Cohen's theories.

Face

• "Women show more of their upper incisors than men, while men display more of their lower central incisors than women."
  (da Motta, Andrea Fonseca Jardim, et al. "Display of the incisors as functions of age and gender." Australian orthodontic journal 26.1 (2010): 27.)
  Caution: the study also found that older Brazilians display less of their upper central incisors and more of their lower central incisors than young Brazilians
• "The mesiodistal dimensions of the right and left maxillary (permanent) canines and central incisors were significantly different (larger) in males when compared to females." In other words: male permanent canines and central incisors of the upper jaw are significantly "broader" in males (for a picture of the measurement taken, see the study paper).
  (Srivastava, Rahul, et al. "Gender determination from the mesiodistal dimension of permanent maxillary incisors and canines: An odontometric study." Journal of Indian Academy of Oral Medicine and Radiology 26.3 (2014): 287.)
•