A major update has been made on the Neanderthal theory. All of the research articles written, some of which are now published, have been added to the neurodiversity section, along with brief descriptions. Some questionable material has been removed, and it is now a lot closer to a professional format suitable for publication.
I’ve made a new research project with some promising possibilities. I went through all 1,800 questions that has been in Aspie Quiz looking for gender bias in the Aspie population where there was none in the neurotypical population (or a reversed bias). While there are quite a few questions that have a gender bias in both populations (a rough estimate is at least 10%, or several hundred questions), it was far harder to find a gender bias only in the Aspie population. I ended up with a list of 47 possible questions. Some of these were discarded based on other datasets, while some were already a permanent part of final version 2 of Aspie Quiz. I tested 36 of the questions in Aspie Quiz to try to confirm the gender bias. It turned out that 17 of these did have a gender bias in the new dataset (with a little more than 9,000 answers), a majority of which was related to female Aspies.
The following issues were biased in the male population:
The following issues were biased in the female population:
Basically, all the biased questions are primarily linked to Aspie groups (15 of 17), with the exceptions needing further research in order to find the key trait. For instance, being asexual is related to many different groups, so is probably a result of several factors, but one of them should be a key Aspie trait. Asexual also has a considerable correlation to dislike for touch / hugs, which is also biased in a similar fashion, and relates to both sensory issues and NT social issues.
In summary, it seems like the traits are related to three different domains:
The gender biases in hunting behavior might mean that Neanderthal females had some specific hunting roles, namely to keep track of animals and their behavior.
The gender bias in mating behavior needs further research. It is clear that both genders experience stronger attachments than normal, and that this seems to give different outcomes with males bonding quicker and having more failures in relationships. A key research area is to elaborate on why asexuality is biased only in the female Aspie population.
The gender bias in nonverbal communication provide key traits that might be used to signal interest. Research on this in the neurotypical population seems to show that females have some unique courtship behaviors, which might have some parallels in the Aspie population, but the two would probably be largely incompatible.
23andme, a company that sells genetic tests to individuals, has developped a Neanderthal heritage estimator: http://spittoon.23andme.com/2011/12/15/find-your-inner-neanderthal/. This estimator uses factor analysis on all the single nucleotide polymorphisms (SNPs, currently almost 1 million) that are part of their genetic test. This means we would expect the estimator to give a good indication of the SNPs that were introduced from Neanderthal after they met modern humans some 30,000 to 40,000 years ago. They use native Africans as a control group, so any SNPs that have spread to the whole world would be discarded. Any SNPs that were introduced earlier would also be discarded.
So how does this estimator correlate to neurodiversity (Aspie) score in Aspie Quiz? We would expect a large correlation if recently introduced SNPs from Neanderthal could explain most of today’s human diversity, but this is not the case. With a material of 167 people of European descent (out of totally 94,000) that did both Aspie Quiz and 23andme, there is a correlation of 0.12. That means that p < 0.07 that there is no relation between 23andme Neanderthal heritage percentage and Aspie Quiz scores (and that there is 93% probability that they are related).
So it does seem like 23andme Neanderthal heritage estimator does support the Neanderthal theory, but the correlation is much smaller than what we would expect. There could be many reasons for this low correlation, but the major reason is probably that science has not found any single SNP that could explain more than 1% of ASD. Since ASDs have no large relation to SNPs, we would not expect it to have a large correlation to any SNP-based genetic data. The largest genetic correlation is with Copy Number Variation (CNVs), but the Neanderthal genome does not include CNVs, and is composed of many small fragments that could prove hard to analyse in the context of CNVs.
Some further break-down of the data reveal other interesting insights. It seems like some questions in Aspie Quiz have larger correlation to 23andme than others. It is especially notable that questions related to Neurotypical compulsions and Aspie hunting seem to have considerably higher correlations to 23andme than others. These issues are atypical in the analysis of Aspie Quiz since they have too low diversity in relation to the number of different issues they cover. They seem to be recent evolution in modern humans (Neurotypical compulsion) and Neanderthal (Aspie hunting). This can explain why the correlation is lower than expected. What the 23andme estimator calculate is recent evolution in modern humans and Neanderthal, but most of the diversity in Aspie Quiz is much older than the 250,000 years that Neanderthal existed. In fact, Aspie Quiz suggests that neurodiversity is close to 2 million years old, meaning that only 10-15% of neurodiversity would be anticipated to have evolved in Neanderthal, while the other traits evolved in their ancestors in Eurasia.
But why then do 23andme mainly detect recent human evolution, and not the more ancient evolution of neurodiversity in Eurasia? Most likely because some of this diversity has spread one way or another back to Africa during the last two million years, and when the SNPs already exist in some (possibly low) proportion among Africans, 23andme would discard them as not of Neanderthal origin.
There is a new study comparing modern human and Neanderthal brain cases. Link: http://news.sciencemag.org/sciencenow/2010/11/neandertal-brains-developed-more.html?etoc
The study concludes that Neanderthal did not have the same development regarding language and complex social networks. They speculate that they were less good at language and trade.
Regarding trade, this is supported in the book “Desolate landscapes” that concludes that Neanderthal seemed to use raw materials from their surroundings while modern humans seem to have traded a lot more as evidenced by long distance movements of raw materials. So, this notion is supported by archeology.
Regarding language, it could very well be that Neanderthal had differences in language and language acquisition. It is quite possible that their language use were related to imitiation of animal sounds rather than social learning of language. As previously posted, autistics do not acquire language the same way as neurotypicals do. Small isolated groups also do not lend themselves to the same type of language use that is typical for modern humans.
It is evident that these findings fits perfectly well into the Neanderthal theory. It is in the areas of language and social networks that Aspies lack adaptations that neurotypicals have. Neanderthals instead had a different set of social adaptations for living in small groups.
Similiarily as the physical traits, it should be possible to discriminate Aspies from neurotypicals based on brain anatomy. There is a recent study on this subject here: http://www.jneurosci.org/cgi/content/full/30/32/10612.
The popular press makes it sound like psychiatry has finally found the brain defect that will enable us to diagnose ASDs on physical traits, and in the end identify the defect and dispose of it. This is hardly what the study found.
The study found that if 20 people with ASDs and 20 neurotypicals where mass-surveyed for every possible anatomical difference, they were able to place them in the correct category with very high confidence.
The method used looks an awfully lot like the factor-analysis method that Aspie-quiz used to obtain weight factors for being Aspie and neurotypical, and which made it possible to classify people without a maunal scoring algorithm. The researchers have basically replicated the Aspie-quiz method, albeit with a data-set of 40 where Aspie-quiz used 150,000.
The results seems similar as well. They found that no single difference can provide good discrimination between groups, but instead there is a need to use many different meassures. These were related to volume and geometry, and existed in many different areas of the brain and in both hemispheres (even if one were more relevant than the other). This is what Aspie-quiz found as well. There was a need for about 150 diverse personality-traits in order to make good judgements for people’s Aspie-NT profile.
The study also found that ADHD was less well defined, which is expected when ADHD is mostly related to a single dimension in the Aspie profile (Aspie social).
This kind of distribution of many different brain differences being related to ASCs is what the Neanderthal theory expects us to see. The authors provide no real theory for how their findings could be explained, but the Neanderthal theory explains it very well.
It is necesary to point out that the small sample size and large amount of differences tested makes this a data-mining project with many possible problems. In the worse scenario, a new sample of 20+20 individuals might fail totally in placing participants in the correct groups if the differences found are only particular to the subjects used.
There is a relatively large study in the Netherlands about physical characteristics of non-mentally retarded children with ASD.
Link: http://www.springerlink.com/content/ck441558236x33w7/fulltext.pdf
While the people behind this study probably didn’t reflect on the traits they have found, many of them seem to be physical Neanderthal traits.
Definite Neanderthal traits
* Eyes deeply set. Reference: “Close-set small eyes are deeply sunk under the “visor” of the heavy brow ridges”.
* Prominent premaxilla. Reference “Morphologic study of the premaxillary suture at its different borders (i.e. the nasal aspect of the frontal process, nasal and palatal aspects of the palatal process of the maxilla) indicates a persistence of the suture among very young Neandertal children in comparison to the condition in extant ones.”
* Palate high/narrow. Reference “The palate is narrow and extremely high.”
* Macrodontia/teeth asymmetry/abnormally shaped teeth. Reference “Taurodontism is a condition found in molar teeth where the body of the tooth and pulp chamber is enlarged vertically at the expense of the roots.” “The condition is of anthropological importance as it was seen in Neanderthals.”
* Large nose. Reference “The Neanderthal’s huge nose is a fluke of evolution, not some grand adaptation, research suggests.”
* Nose bridge prominent. Reference “And heavy supraorbital ridges met across the bridge of the nose.”
* Nose concave. Reference “A concave, angled nasal profile.”
* Lower jaw prominent. Reference “The concept of forceful chewing is also evidenced by the heavy jaw.”
* Toes widely spaced. Reference “a gap of 1.6 cm marks the separation of big and second toes.”
Definite non-Neanderthal traits
There are no definite evidence of traits that could not have been of Neanderthal origin.
Inconclusive
* Brachycephaly. Reference “I believe strongly in neanderthal origins of europeans. Another fact is that we find brachycephal neanderthals exactly where today live dinaric people (Brachycephal); the only brachycephalic neanderthals are those of Crapina and Vindija caves in Croatia.
Others were dolichocephalic, as are the people of the same places today.”
Traits that cannot be assessed
* Face coarse
* Forehead prominent Neanderthal had prominent brow ridges and a low sloping forehead. It is not straight-forward if this means they had prominent forehead or not.
* Macrostomia
* Microstomia
* Short philtrum
* Upper lip cupid bow
* Long uvula
* Ear low-set
* Ear posteriorly rotated
* Ear lobe crease
* Toes syndactyly
* Hypermobile/hyperlax joints
* Multiple nevi
* Hypo-/depigmentation patches
* Open mouth appearance
* Abnormal whorl (non-frontal)
* Full cheeks
* Periorbital fullness
* Eyebrows arched
* Lower lip full
* Upper lip thin
* Prominent philtrum
* Dimpled/grooved chin
* Prominent ear
* Ear lobes attached
* Inverted nipples
* Dry skin
* Nails striped
* Toe proportions
Unintersting traits
* Face asymmetry
* Eyes asymmetry
* Mounth asymmetry
* Halluces valgus
* Face expression less/dull
* Clinodactyly
* Pes Planus (flat feet)
Conclusion
Nine of the traits had a definite Neanderthal connection, one was questionable, and 29 could not be assessed due to them not being related to bone structure. None of the traits could be ruled out as definitely not of Neanderthal origin. An additional seven traits are probably related to problems with hybridization (mostly asymmetry).
So the first draft of the Neanderthal genome has now been published (http://www.sciencemag.org/cgi/content/full/328/5979/710). The authors found that Neanderthals contributed 1-4% to the genomes of non-Africans. They use SNPs and five full genomes from different ethnic groups to arrive at this conclusion. Aspie-quiz has also found that all non-Africans have similar levels of Aspie-traits, while people of African descent have much lower levels of Aspie-traits (1/6th for African-Americans), and might even totally lack these traits when unmixed with non-Africans.
The study claims that admixture most likely occured in Middle East, but this is not supported by Aspie-quiz. Aspie-quiz instead seems to indicate that East Asians mixed with Neanderthal before Europeans. Aspie-quiz also give native American Indians the highest scores of any population, and thus it seems like they have the largest Aspie rate in the world. South Asians are lower than Europeans and East Asians. There is a cline in Eurasia where the north has much higher Aspie-rates than the south. This could be compatible with interbreeding in the Middle East, and later African migration into south Asia, but it matches the “southern migration route” of modern humans far better. Under this scenario, Africans and south Asians are largely devoid of primary interbreeding with Neanderthal. Interbreeding started in Central Asia, and this population then split into a western part that ended up in Europe and formed Caucasians, and an eastern part that ended up in East Asia and formed Mongoloids and Native Americans. Native Americans then got isolated from further gene-flow from South Asia, and thus today has the world’s highest level of Neanderthal ancestry.
The 1-4% of Neanderthal ancestry probably refers to neurotypicals only. Typical Aspie scores for neurotypical people are around 40-50. Typical Aspie scores for Aspies are three times larger. We would therefore assume that Aspies perhaps has 5-15% of Neanderthal ancestry using this as an indication. OTOH, if we assume that 1-4% is the average Neanderthal ancestry in Eurasia, and that all of this is attributable to Aspie traits, and the proportion of Aspie traits is around 10%, it would mean that Aspie traits have 10-40% of Neanderthal ancestry.
Another recently published article on the same theme came to similar conclusions (http://www.nature.com/news/2010/100420/full/news.2010.194.html). Although, here the authors see two different hybridization events. This scenario in fact is supported in Aspie-quiz. Not only is there a signature of Neanderthal interbreeding leading to the introduction of the Aspie-traits, but there is also a signature of the introduction of “neurotypical compulsion” traits that essentially describes modern humans.
To resolve these issues there is a need to sequence full genomes of Aspies.
Ordinary hunting is usually a group activity. Part of the tactic is to scare animals out of their hiding places so strategically placed hunters can throw spears at them (or use fire-arms in the modern variant), wound them, and ultimately, kill them from a distance. This type of hunting is erratic in nature, and usually has rather poor outcome and has to be carried out many times before it is successful. Many of today’s sport games resemble such hunting, especially team-sports.
The Aspie hunting group has caused lots of confusion among people that do Aspie-quiz. This is probably because hunting is usually associated with guns, throwing spears and killing animals at a distance. The questions in this category in Aspie-quiz give no associations at all to this kind of hunting.
So what then is Aspie hunting? The history behind the traits is pretty long. The habitat traits (like liking slowly flowing water) were introduced very early in the evolution of Aspie-quiz, but at that time was not thought to be hunting traits. The main traits, however, are more recent, and were used to evaluate Valerius Geist’s Neanderthal paradigm.
Geist’s Neanderthal paradigm was published in the 1970s and was a novel way to solve several mysteries about Neanderthal tools and why they selected the prey species they did. A central observation by Geist was that all prey species had fur. He therefore presumed that Neanderthal’s had used this property of their prey in their hunting tactics. The Mousterian tool-kit also seem to lack throwing spears, and instead contains larger tools that seems to work a lot better as stabbing spears. The rodeo-like injuries of Neanderthal are also largely unexplained by proponents that like to think that Neanderthals must have been hunting in the same manner as us, only less successfully, and with cruder weapons.
While Valerius Geists hypothesis goes a long way at explaining the archeology, it says little about the psychology and specific adaptations of Neanderthal. These aspects were researched in Aspie-quiz to try to confirm (or disprove) Geists hypothesis. There were a lot of predictions from the hypothesis that could be tested.
The following traits were predictions (listed with their predicted function) that were highly successful (correlated well with Aspie score and each others):
A few of the physical traits got no relevance to being Aspie, but still correlated with Aspie hunting. Typically, these traits are believed to be part of the motor problems of Aspies, and thus have an inherit bias against them:
Some other traits also related to Aspie-hunting
It is notable that perception issues correlate closely to Aspie hunting. The relation here seems to be obvious. Highly sensitive senses is important for passive hunting, especially hearing (sounds that animals make), tactile (vibrations that animals make) and smell (tracking an animal). Acute vision and detail perception are also related to finding signs of an animal that are not required with the usual hunting method that favors getting an whole picture of the environment. These things also extend to paranormal experience.
Additionally, many stims (Aspie-quiz defines these as Aspie communication) are related to Aspie hunting. For instance, spinning in circles, walking on toes and mimicking animal sounds could be characterized as both stims and hunting-related traits. The relation here is probably that Neanderthals adapted their nonverbal communication to their prey animals, and thus gained increased hunting success by being able to better understand their prey. This is also why Aspies today say they can both naturally interpret animals and cannot naturally interpret neurotypical humans. The communication traits are based on a difference, not an absence. There are also nonverbal communication traits that seems to be shared among Aspies, and that can be used to identify Aspies.
The habitat traits (that correlate with the pure hunting adaptations are these):
From these we can presume that Neanderthals probably selected their ambush places near water. The like for mist and fog could be a hunting preference, or it could be an adaptation to living near glacials, which would produce mist / fog. We can also presume that Neanderthals hunted in forrests, not in open environments. Their tactic would be far more successful in a forrest than on the open plain, and similarily, the modern hunting tactic is more successful in a relatively open terrain.
Other types of traits can also be associated with Aspie hunting. For instance, it is not a long-shot to propose that special interests and the splinter-skills of Savants are related to passive hunting. Passive hunting requires lots of creative talents and persistence for success. Obsessions can also easily be entered into the equation. Once a hunter has found a successful way to bring down a prey, he/she is likely to keep to it, and only modify it slightly to make it more successful. The erratic methods of modern human hunting do not lend themselves to doing things in the same way, and thus such obsessions are absent in neurotypicals. Neurotypical people instead have people obsessions, as these are central for group-hunting.
In sumary, understanding Aspie/Neanderthal hunting seems to be central for understanding most parts of the autistic spectrum.
The excellent book The biology of Religious Behavior edited by Jay R Feierman provides an excellent framework on how to understand the biology and evolution of religion.
Viewed from a neurodiversity-perspective, there are certain troublesome aspects of religious behaviors:
The Neanderthal Theory proposes that neurodiversity-traits are of neanderthal origin. So how could the current religious behaviors have evolved? Since major components seems to be recent, but of different origin, it is probably necesary to analyze African/Asian modern humans separately from Neanderthals, and try to figure out what was common before the split of humans into Eurasian Neanderthals and African/South Asian Homo, what evolved later in African/South Asian Homo, what was introgressed from Neanderthal, and how this admixture contributed to today’s religious behaviors.
We today know from many finds in Africa that symbolism, ornamentation and similar behaviors evolved there at the time of the emergence of modern humans. These behaviors group with neurotypical compulsion in Aspie-quiz, and also contain status, reputation and gossip. These are clearly the prosocial dimension of religious behavior described in the book. It works just as well to differentiate an ingroup based on cloth or ornamentation as on supernatural beliefs. In fact, cloth and music taste are the behaviors that often define groups in secular societies. So, it is logical to propose that pre-hybrid modern humans evolved the prosocial dimension of religious behaviors, but probably not in the context of supernatural beliefs, but more likely based on possessings and ornamentation.
When it comes to supernatural beliefs and music, the evidence is in favor of a Neanderthal origin. All the questions in Aspie-quiz about supernatural beliefs cluster together, and when the groups in Aspie-quiz were reduced to six neurotypical and six Aspie groups (with the same names), the supernatural group was merged into Aspie perception. These traits have no relation at all to the prosocial behaviors in neurotypical compulsion.
Aspie perception contains a wide range of more sensitive senses and reduced pain sensitivity. This increased sensitivity developed as a natural adaptation to Neanderthal passive hunting (Aspie hunting). Aspie hunting is closely related to Aspie perception, and contains traits like mimicking animal sounds, making traps and alike. Neanderthal hunting, unlike the group hunting of modern humans, would be conductive to developing a very fine-tuned psychology of the prey animals, including mimicking their sounds and understanding their behaviors. This is called animanism in the book, and it is clearly a neurodiversity trait. It is also the case that stims (called self-stimulatory or repetitive behaviors by psychiatry, but related to Aspie communication in Aspie-quiz) are strongly related to Aspie hunting. Mimicking animal sounds fits both as a stim and as an passive hunting trait. Thus, we might presume that the nonverbal communication behaviors of Neanderthals evolved to be useful for passive hunting and to trick prey animals. This has some interesting predictions regarding mirror neurons that are also described in the book. More likely, the relevance of mirror neurons is not for neurotypicals, but for the Aspie variant of mirror neurons, as it was Neanderthals that adapted their mirror neurons to be extra sensitive to their prey animals, and not modern humans.
When it comes to music, the first musical instruments are found in Europe, not in Africa. These are flutes. Flutes and musical instruments fits well with tricking animals. They still functioned in this way in pastoral settings in Sweden only a century ago. They have no obvious function in relation to the prosocial behaviors of modern humans.
So, it makes sense that highly sensitive senses, musical ability and superior understanding of animal behavior and communication were Neanderthal traits that introgressed into modern humans. These abilities proved useful in their new context, and as a consequence some of the bearers were recruited as shamans, witch-doctors and healers. Later, these “mystical” traits were exaptated into the prosocial behaviors as belief in supernatural things, as people could not understand the extra-sensitive abilities of these people.
Adding to the evidence is that fasting and enduring pain are also neurodiversity-traits. These were traits associated with the shamanistic phenotype.