Brain development and Neoteny / Neuroscience

J Psychiatry Neurosci. 2011 Nov;36(6):412-21. doi: 10.1503/jpn.100138.

Can Asperger syndrome be distinguished from autism? An anatomic likelihood meta-analysis of MRI studies.

Yu KK1, Cheung C, Chua SE, McAlonan GM

Whereas grey matter differences in people with Asperger syndrome compared with controls are sparser than those reported in studies of people with autism, the distribution and direction of differences in each category are distinctive.


In development, timing is of the utmost importance, and the timing of developmental processes often changes as organisms evolve. In human evolution, developmental retardation, or neoteny, has been proposed as a possible mechanism that contributed to the rise of many human-specific features, including an increase in brain size and the emergence of human-specific cognitive traits. We analyzed mRNA expression in the prefrontal cortex of humans, chimpanzees, and rhesus macaques to determine whether human-specific neotenic changes are present at the gene expression level. We show that the brain transcriptome (transcriptome includes all mRNA transcripts in the cell; it reflects the genes that are being actively expressed at any given time, with the exception of mRNA degradation phenomena such as transcriptional attenuation.) is dramatically remodeled during postnatal development and that developmental changes in the human brain are indeed delayed relative to other primates. This delay is not uniform across the human transcriptome but affects a specific subset of genes that play a potential role in neural development.


By comparing the gene expression profiles in human, chimpanzee, and rhesus macaque prefrontal cortices throughout postnatal development, we have found that there is no uniform shift in the developmental timing between humans and other primates. We find instead a significant excess of genes showing neotenic expression in humans. This result is in line with the neoteny hypothesis of human evolution (6) and provides insight into the possible functional role of neoteny in human brain development. Specifically, we show that at least in one of the 2 cortical regions studied, the neotenic shift is most pronounced at the time when humans approach sexual maturity, (body matures; brain does not) a process known to be delayed in humans relative to chimpanzees or other primates (6, 24). Furthermore, the neotenic shift particularly affects a group of genes preferentially expressed in gray matter. Intriguingly, the timing of the shift also corresponds to a period of substantial cortical reorganization characterized by a decrease in gray-matter volume, which is thought to be related to synaptic elimination (21, 25, 26). The developmental pace of changes in gray-matter volume has been associated with the development of cognitive skills among humans (e.g., linguistic skills) (27) as well as with the development of disorders (e.g., attention-deficit/hyperactivity disorder) (28).

Although the precise causes and consequences of the human neotenic shift remain unknown, together these observations suggest that ontogenetic timing differences between the human and the chimpanzee prefrontal cortex transcriptomes may reflect differences in sexual and cognitive maturation between the 2 species. According to this logic, delayed gray-matter maturation in the human prefrontal cortex may extend the period of neuronal plasticity associated with active learning, thus providing humans with additional time to acquire knowledge and skills.



Things to think about:

Maturation of gray matter in the human prefrontal cortex is delayed by neotenic shifts. Developmental delay is neotenic. There is a “fuzzy boundary” (?) between too much / too little grey matter volume for the brain to function well; there also seem to be 2 types of brain organization: social navigation vs. factual and problem-solving. (See today’s Temple Grandin post.) These are probably not ‘separate’ paths, but are developmental stages. (Social is juvenile; factual is adult.)

The gray matter volume in any specific human brain may vary between mature and neotenic states. Humans vary in degrees of neoteny. It might be more accurate to dump “Autism Spectrum” for an inclusive classification “The Neoteny Spectrum” which includes all contemporary homo sapiens.

How do we know which human brains (volume of grey matter) are mature and which are neotenic? What volume of grey matter is the reference for maturity vs. neoteny? We can begin with behavior.

Some changes in grey matter volume occur during puberty: therefore it would be useful to compare the pre-puberty and post-puberty states of grey matter in individuals, especially those diagnosed with a “brain disorder” in early childhood. Mixing data from before and after stages of brain reorganization may be completely misleading do to variations in timing.

Grey matter differences in individuals reflects maturity vs. neoteny (a spectrum of rates of development) and not fundamental developmental disability; if one is ONLY interested in “The Social Brain,” and designates this juvenile stage of development as the ONLY legitimate human brain, then the “problem” of Asperger’s is the product of inattentional blindness and ignorance. Bad science!

CASE IN POINT: It is said that Asperger’s have “less than normal” volumes of gray matter, but if this conclusion has been derived from pre-puberty testing, then it is entirely possible that Asperger children, in terms of specific brain development, (intellect, language, concrete – visual thinking, facts and problem-solving) simply MATURE FASTER – and gray matter volume is reduced to a more effective and efficient volume well before their peers.

Social brains are neotenic; the neurotypical neotenic brain never fully matures. Which means that the social orientation (obsession) of modern social humans is the product of extreme neoteny.   Neoteny is evident in a lack of logic, rationality, analytical thinking and effective problem-solving, which are absent in everyday life and most seriously, in our political leaders.

“Juvenile” neotenic behavior is evident in the inability to recognize that facts and physical reality exist. Instead, emotions are paramount; self absorption is rampant, magical thinking prevails, action is missing, narcissitic orientation is “normal”, and “worship of” childlike celebrities is a substitute for adult models and personal development. Adult children never leave home but remain dependent on parental support. Violence is characteristic of juvenile males; violent behavior usually decreases as males age, but today “frivolous” violence is the perpetual activity of neotenic males and is encouraged by popular culture.


Cerebral Asymmetry / Asperger Brain Differences

Philosophical Transactions of the Royal Society / Biological sciences

The evolution and genetics of cerebral asymmetry

Michael C Corballis

Immune System Introgressions / Neandertal, Denisovan HLA alleles

Neanderthal, State Museum, Halle, Germany

Denisovan admix today: Low – Black / High – Red


The Shaping of Modern Human Immune Systems by Multiregional Admixture with Archaic Humans

Laurent Abi-Rached,1 (see original paper for list of authors)


Whole genome comparisons identified introgression from archaic to modern humans. Our analysis of highly polymorphic HLA class I, vital immune system components subject to strong balancing selection, shows how modern humans acquired the HLA-B*73 allele in west Asia through admixture with archaic humans called Denisovans, a likely sister group to the Neandertals. Virtual genotyping of Denisovan and Neandertal genomes identified archaic HLA haplotypes carrying functionally distinctive alleles that have introgressed into modern Eurasian and Oceanian populations. These alleles, of which several encode unique or strong ligands for natural killer cell receptors, now represent more than half the HLA alleles of modern Eurasians and also appear to have been later introduced into Africans. Thus, adaptive introgression of archaic alleles has significantly shaped modern human immune systems.

Example: Includes similar graphics for Neanderthal and Denisovan HLA alleles

Fig. 3 Effect of adaptive introgression of Neandertal HLA class I alleles on modern human populations. (A) All six Neandertal HLA-A, -B and -C alleles are identical to modern HLA class I alleles…


Inflammatory Diseases, Deadly Modern Environments / ASD, Depression

quick summation from Torrey Institute for Molecular Studies: 

Inflammatory Disorders (click here for website)

Inflammation is the body’s protective response to injury and infection; it is a complex process involving many cell types, as well as different components of blood.

The inflammatory process works quickly to destroy and eliminate foreign and damaged cells, and to isolate the infected or injured tissues from the rest of the body. Inflammatory disorders arise when inflammation becomes uncontrolled, and causes destruction of healthy tissue. There are dozens of inflammatory disorders. Many occur when the immune system mistakenly triggers inflammation in the absence of infection, such as inflammation of the joints in rheumatoid arthritis. Others result from a response to tissue injury or trauma but affect the entire body.

There are many ways by which normal cells and tissues can be damaged during inflammation. One important mechanism is by assembly of a complex of proteins that forms holes on the surface of a cell, where it causes damage and can potentially kill the cell. This complex is called a Membrane Attack Complex or MAC. Torrey Pines Institute researchers are working to understand how MAC contributes to a number of inflammation-associated disorders, including the complications of diabetes and rheumatoid arthritis. Understanding how MAC assembles will provide insights into the design of drugs to prevent inflammatory damage to cells.

Inflammation is also an important secondary component of many diseases. An example of this is atherosclerosis, or hardening of the arteries, where inflammation can cause more damage to arteries in a failed attempt to heal the artery wall. There is also an important link between obesity and inflammation, because substances that promote inflammation are released from fat cells, as well as from other cells embedded in fat tissue. The Institute’s scientists are leading the way in understanding these new and exciting areas of inflammation research.

The first article below presents the hypothesis that psychological stress and depression may be associated with “inflammatory” diseases.

The second presents the evolutionary “Inflammatory Bias” that has lead to rampant inflammatory disease in modern humans.


Article 1: Brain Behav Immun. Author manuscript; available in PMC 2014 Jul 1.

 Published in final edited form as: Brain Behav Immun. 2013 Jul; 31: 1–8. Published online 2013 Apr 30. doi:  10.1016/j.bbi.2013.04.009

Malaise, Melancholia and Madness: The Evolutionary Legacy of an Inflammatory Bias

Technical paper, so I’m looking for a credible translation into common language!

Excerpt that may possibly be significant to ASD, Asperger’s and other “social” disorders.  

 5a. Immune Pathways and the Inflammasome

In a paper in this issue, Iwata et al. propose the provocative hypothesis that the recently characterized inflammasome may serve as a critical link between psychological stress and depression, as well as other illnesses related to inflammation (Iwata et al. 2012).

The inflammasome is a protein complex that can detect diverse danger signals including not only pathogen-associated molecules but also molecules associated with cellular damage such as adenosine triphosphate (ATP). Upon activation, the inflammasome can generate an inflammatory response notably through the production of IL-1-beta by activation of a caspase that cleaves the precursor peptide pro-IL-1-beta. Given the capacity of the inflammasome to react to danger signals generated by stimuli other than pathogens, the authors suggest that the inflammasome may be uniquely poised to serve as the molecular mechanism that transduces psychological responses to stress into an inflammatory response in the absence of pathogen challenge.

Thus, the inflammasome may represent an evolutionary adaptation that extends the immune and behavioral response to pathogens and the microbial world to include challenges emanating from predators, people and the social world. Although of significant value in detecting and responding to tissue damage and destruction, by virtue of the inflammasome,

the inflammatory bias may have been given an entrée into the modern world where people, not pathogens or predators represent the primary challenges.


Article 2:

The role of inflammation in depression: from evolutionary imperative to modern treatment target

Andrew G. Miller and Charles L. Raison

Nature Reviews Immunology Volume:16,Pages:22–34Year published:(2016)DOI:doi:10.1038/nri.2015.5 (click to access article)

Fig. 1 Evolutionary legacy of an inflammatory bias. Early evolutionary pressures derived from human interactions with pathogens, predators and human conspecifics (such as rivals) resulted in an inflammatory bias that included an integrated suite of immunological and behavioural responses that conserved energy for fighting infection and healing wounds, while maintaining vigilance against attack.This inflammatory bias is believed to have been held in check during much of human evolution by exposure to minimally pathogenic, tolerogenic organisms in traditional (that is, rural) environments that engendered immunological responses characterized by the induction of regulatory T (TReg) cells, regulatory B (BReg) cells and immunoregulatory M2 macrophages as well as the production of the anti-inflammatory cytokines interleukin-10 (IL-10) and transforming growth factor-β (TGFβ). In modern times, sanitized urban environments of more developed societies are rife with psychological challenges but generally lacking in the types of infectious challenges that were primary sources of morbidity and mortality across most of human evolution. In the absence of traditional immunological checks and balances, the psychological challenges of the modern world instigate ancestral immunological and behavioural repertoires that represent a decided liability, such as high rates of various inflammation-related disorders including depression.

In proper perspective, modern social environments ARE DEADLY to life; not only to ASD Asperger people, but to ALL HUMANS and to every species that we are driving to extinction – Mass extinction is the likely outcome.


Neanderthal- H. Sapiens Ancestral Gene EXCHANGE

Neanderthal inheritance helped humans adapt to life outside of Africa / November 10, 2016

Read more at:

Excerpt: All told, the new study identifies 126 different places in the genome where genes inherited from those archaic humans remain at unusually high frequency in the genomes of modern humans around the world. We owe our long-lost hominid relatives for various traits, and especially those related to our immune systems and skin, the evidence shows.

“Our work shows that hybridization was not just some curious side note to human history, but had important consequences and contributed to our ancestors’ ability to adapt to different environments as they dispersed throughout the world,” says Joshua Akey of University of Washington School of Medicine in Seattle.

While the vast majority of surviving Neanderthal and Denisovan sequences are found at relatively low frequencies (typically less than 5%), the new analyses turned up 126 places in our genomes where these archaic sequences exist at much higher frequencies, reaching up to about 65%. Seven of those regions were found in parts of the genome known to play a role in characteristics of our skin. Another 31 are involved in immunity.

“The ability to increase to such high population frequencies was most likely facilitated because these sequences were advantageous,” Akey explains. “In addition, many of the high-frequency sequences span genes involved in the immune system, which is a frequent target of adaptive evolution.”

Generally speaking, the genes humans got from Neanderthals or Denisovans are important for our interactions with the environment. The evidence suggests that hybridization with archaic humans as our ancient ancestors made their way out of Africa “was an efficient way for modern humans to quickly adapt to the new environments they were encountering.”

Reconstruction by Fabrio Fogliazza /

Neanderthals mated with modern humans much earlier than previously thought

February 17, 2016

Melanesians / Neanderthal and Denisovan DNA Re-Post

Pacific islanders got a double whammy of Stone Age DNA

Melanesians only people known to inherit substantial DNA from both Neandertals, Denisovans

March 17, 2016


Modern-day Melanesians carry a two-pronged genetic legacy of ancient interbreeding that still affects their health and well-being, researchers say.

Unlike people elsewhere in the world, these Pacific islanders possess nuclear DNA that they inherited from two Stone Age hominid populations, say population geneticist Benjamin Vernot, formerly of the University of Washington in Seattle, and his colleagues. At least some of that ancient DNA contains genes involved in important biological functions, the researchers find. Nuclear DNA is passed from both parents to their children.


Woman from Bismarck Archipelago: photo 1911.

The finding means that ancestors of people now living in the Bismarck Archipelago, a group of islands off Papua New Guinea’s northeastern coast, mated with Neandertals as well as with mysterious Neandertal relatives called Denisovans, the scientists conclude online March 17 in Science.

In support of previous research, the researchers find that non-Africans — including Melanesians — have inherited an average of between 1.5 and 4 percent of their DNA from Neandertals. But only Melanesians display substantial Denisovan ancestry, which makes up 1.9 to 3.4 percent of their DNA, the researchers say. (Present-day African populations possess little to no Neandertal or Denisovan DNA.)

The bits of Neandertal and Denisovan DNA carried by Melanesians encompass genes involved in metabolism and immunity, indicating that interbreeding influenced the evolutionary success of ancient humans, Vernot’s group reports.

The new study reconstructs the microscopic landscape of Neandertals’ and Denisovans’ contributions to Melanesians’ DNA “in impressive detail,” says Harvard University paleogeneticist Pontus Skoglund.

Vernot’s team studied DNA from 35 Melanesians at 11 locations in the Bismarck Archipelago. Analyses concentrated on DNA from 27 unrelated individuals. The researchers also looked for evidence of ancient interbreeding in previously acquired genomes of close to 1,500 modern-day individuals from different parts of the world. Denisovan DNA for comparisons came from fragmentary fossils found in a Siberian cave; comparative Neandertal DNA came from a genome previously extracted from a 50,000-year-old woman’s toe bone.

Among Melanesians, DNA sequences attributed to Neandertals and Denisovans encompassed several metabolism genes. One of those genes influences a hormone that increases blood glucose levels. Another affects the chemical breakdown of lipids. Other Melanesian genetic sequences acquired through ancient interbreeding either include or adjoin genes that help to marshal the body’s defenses against illness.

These findings follow evidence suggesting that once-useful genes that ancient humans inherited from Neandertals now raise the risk of contracting certain diseases (SN: 3/5/16, p. 18). Vernot’s group reaches no conclusions about good or bad effects of ancient hybrid genes in Melanesians.

No sign of Neandertal or Denisovan DNA appears in areas of Melanesians’ genomes involved in brain development, the scientists say. So brain genetics, for better or worse, apparently evolved along a purely human path.

Denisovans’ evolutionary history remains poorly understood. Previous DNA comparisons suggest that Denisovans must have reached Southeast Asia. Skoglund suspects that’s where the ancestors of Melanesians bred with Denisovans.

Substantial interbreeding of humans with Denisovans probably occurred only once, Vernot and his colleagues suspect. Genetic exchanges of humans with Neandertals took place at least three times, they add. These estimates are derived from comparisons of shared Denisovan and Neandertal DNA sequences among individuals in different parts of the world.


Story today on a news website in India:

New York: An international team of scientists has discovered that residents of the remote equatorial islands of Melanesia share fragments of genetic code with two extinct human species.

The researchers compared the DNA sequences of 35 modern people living on islands off the coast of New Guinea with DNA drawn from two early human species: Denisovans, whose remains were found in Siberia, and Neanderthals, first discovered in Germany.

“Substantial amounts of Neanderthal and Denisovan DNA can now be robustly identified in the genomes of present-day Melanesians, allowing new insights into human evolutionary history,” the study said.

“As genome-scale data from worldwide populations continues to accumulate, a nearly complete catalog of surviving archaic lineages may soon be within reach,” the study noted.

The findings were published in the journal Science.

Th researchers collected the modern-day blood samples used in the study about 15 years ago in Melanesia. This is the first time full genomes from those samples have been sequenced.

“I’m surprised that these Neanderthal and Denisovan genomes made it out to this remote place,” said one of the researchers Andrew Merriwether, molecular anthropologist at Binghamton University in New York.

“We know people have been there for at least 48,000 years because we find human remains that go back that far, but no one has ever been able to connect them to any other place. When you compare most of their genome sequences, they don’t cluster with any other group. They’ve been there and been isolated for a very, very long time,” Merriwether noted.

Studies like this one may enable scientists to answer big questions about human migrations and evolution thousands of years ago.

How did ancient humans travel — and cross the ocean — to get to Melanesia, and when and where did the Denisovan DNA enter our gene pool? 

The researchers believe that sequencing of additional DNA samples found in Asia may one day help to answer those questions.


First Published: Friday, March 18, 2016 – 17:41



Pit of Bones (Sima Huesos) hominins are Neanderthal Re-Post

Another “rush to judgement” error.

Sima de los Huesos Hominins Were Actually Early Neanderthals, Say Anthropologists

Mar 15, 2016 by Enrico de Lazaro

The Sima de los Huesos, or the Pit of Bones, is a cave site in Atapuerca Mountains, Spain, dated to around 430,000 years ago (Middle Pleistocene). It preserves a large collection of fossils attributed to an enigmatic species — the Sima de los Huesos hominin.

The site has been excavated continuously since 1984. After thirty years, archaeologists have recovered nearly 7,000 fossils corresponding to all skeletal regions of at least 28 individuals.


Another archaic human experiences an identity crisis.

“A unique assemblage of 28 hominin individuals, found in Sima de los Huesos, has recently been dated to approximately 430,000 years ago,” explained Dr. Meyer and his colleagues from Spain, Canada, Germany and the United Kingdom.

“An interesting question is how these Middle Pleistocene hominins were related to those who lived in the Late Pleistocene epoch, in particular to Neanderthals in western Eurasia and to Denisovans, a sister group of Neanderthals so far known only from southern Siberia,” they said.

Previous analyses of the Sima de los Huesos hominins in 2013 showed that their maternally inherited mitochondrial DNA (mtDNA) was distantly related to Denisovans, a recently-discovered early human species.

The new results, appearing in the journal Nature, show that the hominins were indeed early Neanderthals.

“We recover nuclear DNA sequences from two specimens, which show that the Sima de los Huesos hominins were related to Neanderthals rather than to Denisovans, indicating that the population divergence between Neanderthals and Denisovans predates 430,000 years ago,” the scientists said.

“These results provide important anchor points in the timeline of human evolution,” said team member Dr. Svante Pääbo, also from the Max Planck Institute for Evolutionary Anthropology.

“They are consistent with a rather early divergence of 550,000 to 750,000 years ago of the modern human lineage from archaic humans.”

“The recovery of a small part of the nuclear genome from the Sima de los Huesos hominins is not just the result of our continuous efforts in pushing for more sensitive sample isolation and genome sequencing technologies,” Dr. Meyer said.

“This work would have been much more difficult without the special care that was taken during excavation.”

“We have hoped for many years that advances in molecular analysis techniques would one day aid our investigation of this unique assembly of fossils,” added team member Dr. Juan-Luis Arsuaga, of the Complutense University in Madrid, Spain. “We have thus removed some of the specimens with clean instruments and left them embedded in clay to minimize alterations of the material that might take place after excavation.”


Matthias Meyer et al. Nuclear DNA sequences from the Middle Pleistocene Sima de los Huesos hominins. Nature, published online March 14, 2016; doi: 10.1038/nature17405

Chimps / Similar Personality Traits to Humans

Also from Yerkes National Primate Research Center: Chimps’ Gestures Explain how Human Languages Appeared

Weasel words in green. My comments.

Chimpanzees Show Similar Personality Traits to Humans

May 6, 2014 / Georgia State University
Chimpanzees have almost the same personality traits as humans, and they are structured almost identically, according to new work led by researchers at Georgia State University.

The research also shows some of those traits have a neurobiological basis, and that those traits vary according to the biological sex of the individual chimpanzee.

“Our work also demonstrates the promise of using chimpanzee models to investigate the neurobiology of personality processes,” said Assistant Professor Robert Latzman of Psychology, who led the research team. “We know that these processes are associated with a variety of emotional health outcomes. We’re excited to continue investigating these links.”

The team, which also included Professor William Hopkins of Neuroscience, started with a common tool for analyzing chimp personalities called the Chimpanzee Personality Questionnaire.

The questionnaire is filled out by the chimpanzees’ caregivers, (just like Autism questionnaires) who rate individual chimps in 43 categories based on their observation of the animals’ daily behavior. Is the chimp excitable? Impulsive? Playful? Timid? Dominant? (Note that these are human emotion-behavior words – the assumption being that chimps are “just like us” – which is what the psychologists are trying to prove / another “conclusion as hypothesis” error. Also, these “emotions” are highly subjective depending on the human caretaker’s relation to the chimp and degree of anthropomorphic bias. Again! – just like bias in Autism questionnaires. THESE ARE NOT WILD CHIMPS, but thoroughly contaminated-by-humans LABORATORY ANIMALS.

When you think about it, maybe research on enslaved, depressed and zoochotic chimps does produce great models for social typical human personalities and behaviors.

The researchers analyzed complete questionnaires for 174 chimpanzees housed at the Yerkes National Primate Center at Emory University. They ran extensive individual analyses to find out which traits tend to go together, and which combine to make more basic, fundamental “meta-traits.”

The analysis showed that the most fundamental personality trait for chimpanzees is dominance — that is, whether an animal is a generally dominant and under controlled “Alpha,” or a more playful and sociable “Beta.”

But those two big categories can be broken down statistically into smaller personality traits in ways that echo the personality structures researchers have repeatedly found in child and adult human subjects. (Well, duh! If you use a system of human personality traits to evaluate chimps, you are going to get “human” personality traits in chimps. Same goes for dogs… Is the dog excitable? Impulsive? Playful? Timid? Dominant? )

Alpha personalities, for example, statistically break down into tendencies toward dominance and disinhibition. Beta personalities, on the other hand, show low dominance and positive emotionality. (Alpha-Beta are BORROWED from Wolf Pack hierarchy; jargon now transferred to any and all “social” species – really not kosher)

Further analysis shows these lower order traits also can be statistically broken down into their constituent parts. (Which came first? “Analysis – guess” that 5 factors “exist” or are the 5 factors the result of statistical manipulation that “reveals” 5 factors?) The research team identified five personality factors that combine differently in each individual chimpanzee: conscientiousness, dominance, extraversion, agreeableness and intellect. This echoes a well-known five-factor model of the human personality, although the specific factors are slightly different. (Wow! How unconvincing this leap is!)

Now, for the neurobiology: many of those chimpanzee traits statistically correlate with the function of a neuropeptide called vasopressin. (The “love” hormone in monogamous prairie voles) Chimps who were born with a common variant in the genes that control vasopressin behaved differently than their peers, the males showing more dominance and more disinhibition, but the females less of both.

This research shows not only a neurobiological basis for personality, but an evolutionary basis as well. (Sweeping generalization of the type so common in psychology: claim that your flimsy subjective pre-conclusion is “valid” by tacking on “neuro” and “evolution” – so it ‘sounds’ like Science. In fact, it would be impossible for personality TO NOT BE neurobiological, since personality arises in the physical organism: it’s not a “supernatural thing” stuffed into the brain body by imaginary entities – space aliens or elves, or Jesus. – but maybe, since this is Georgia…LOL) The neurobiological bases of personality can vary according to the biological sex of the subject, at least in chimpanzees. Chimpanzee personality appears to have almost the same ingredients as human personalities, and that similarity seems to arise from the species’ similar neurobiology. (Humans and most species equipped with nervous systems have ‘similar’ neurobiology.)

“These results are particularly significant in light of the striking parallels between the major dimensions of personality found between chimpanzees and humans,” said Sam Gosling, professor of psychology at the University of Texas at Austin and an internationally known researcher in cross-species personality research.

“Personality in Chimpanzees (Pan Troglodytes): Exploring the Hierarchical Structure and Associations with the Vasopressin V1A Receptor Gene,” appeared in the April 21 issue of the journal PLOS ONE.

The research was supported by the National Institutes of Health and the National Center for Research Resources.