Autism And The Correlates Of Intelligence
The high intelligence imbalance hypothesis predicts that autism should be associated, at a phenotypic level, with substantiated correlates of intelligence. I elaborate here on the most-notable joint correlates of intelligence and autism, focusing on phenotypes that are associated with intelligence and that are over-developed or over-expressed in autism.
Autism And Human Evolutionary Success
- Date:
- University of York
- Summary:
- A subtle change occurred in our evolutionary history 100,000 years ago that allowed people who thought and behaved differently — such as individuals with autism — to be integrated into society, academics have concluded.
A subtle change occurred in our evolutionary history 100,000 years ago which allowed people who thought and behaved differently such as individuals with autism – to be integrated into society, academics from the University of York have concluded.
The change happened with the emergence of collaborative morality – an investment in the well-being of everyone in the group – and meant people who displayed autistic traits would not only have been accepted but possibly respected for their unique skills.
It is likely our ancestors would have had autism, with genetics suggesting the condition has a long evolutionary history.
But rather than being left behind, or at best tolerated, the research team conclude that many would have played an important role in their social group because of their unique skills and talents.
We are arguing that diversity, variation between people, was probably more significant in human evolutionary success than the characteristics of one person, said Penny Spikins, senior lecturer in the archaeology of human origins, at the University of York.
It was diversity between people which led to human success and it is particularly important as it gives you different specialised roles.
Brain Disorders That Started As Evolutionary Advantages
You know how you can look back at people living 150 years ago and chuckle at how they thought leeches could cure colds and drills could fix headaches? Well, a hundred years from now, that’s how they’ll see our treatment of mental illness . The truth is, we’re just barely figuring out why human brains go wrong the way they do, and the most interesting theories suggest that many times what we now call a disorder used to be an awesome advantage.
For example …
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How Autism Influenced Human Evolution
This article was originally published on The Conversation. Read the original article.
When you think of someone with autism, what do you think of? It might be someone with a special set of talents or unique skillssuch as natural artistic ability or a remarkable memory. It could also be someone with enhanced abilities in engineering or mathematics, or an increased focus on detail.
This is because despite all the negative stories of an “epidemic of autism” most of us recognize that people with autism spectrum conditions bring a whole range of valued skills and talentsboth technical and socialto the workplace and beyond.
Research has also shown that a high number of people not diagnosed with autism have autistic traits. So although many of these people have not been officially diagnosed, they might be were they to go for autism-related tests. These people were unaware they have these traits, don’t complain of any unhappiness, and tend to feel that many of their particular traits are often an advantage.
Autism As The Result Of An Extreme Male Brain
The extreme male brain theory of autism postulates that affected individuals are extremely focused on systemizing as opposed to empathizing . Men, on average, appear to have a more systemizing brain than women, i.e., they are more interested in and better at analyzing variables in a system, and at deriving the rules that govern the behavior of a system. Women, on the other hand, seem to have a more empathizing brain, i.e., they are better at inferring mental states in other people, and to respond appropriately to these mental states. Empirical support for the extreme male brain theory of autism comes from several sources. First, more males are affected by autism than females . Second, high-functioning affected individuals tend to outperform unaffected people with similar IQs on systemizing tasks . Third, the behavioral differences between people with and without autism are mediated by differences at the anatomical level of the brain . Fourth, prenatal exposure to testosterone is positively related to the development of autistic traits .
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Autism And The Archaeological Record Of The Palaeolithic
In the light of the potential value of autistic insight and action in certain contexts it is possible to view the archaeological record rather differently. Rather than a progressive sophistication of a single human mind, a more plausible explanation for much of the patterning in the archaeological record is as the marked emergence of autistic traits within a modern humanity made up of complex interrelationship between different minds .
The earliest evidence for any autistic characteristics emerges well after the split between our own species and our nearest relatives the Neanderthals , perhaps unsurprisingly as some of the key genes for autism have been found to be lacking in the Neanderthal genome and that of the other closely related species to modern humans, the Denisovans .
However after 100,000 years ago various elements of the archaeological record document certain new traits which appear to be linked to autism such as a unique focus on detail, technological innovation, and understanding of complex systems as well as evidence for large scale collaborations in the exchange of materials between groups . Many of these new elements can be associated with what has been termed the appearance of modern human behaviour.
Figure 7.
Figure 8.
Microliths, forming part of highly engineering technologies, only appear after about 100,000 years ago. These microliths are from Red Ratcher Late Mesolithic site in the Pennines .
Figure 9.
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Figure 10.
Figure 13.
New Research Says Autism Genes Win The Competition For Survival Of The Fittest
Autism should have disappeared. If we accept Charles Darwins reasoning, as most biologists do, the incidence of autism in the human population should keep dropping. Traits that promote genetic survival thrive, whereas those that hinder reproduction disappear. Many autistic people do not bear children, so autistic gene variants should be selected out of the gene pool. Instead, autism has either persisted or increased to a rate of one out of every sixty-eight births. Whats up?
One explanation might be that autism results from a de novo mutation in a few genes. The mutation is new to this generation and will disappear after this generation. After all, every person has thousands of mistakes in their genes, but most make no difference in the long run. Periodically, however, one-time mutations do make a difference, as the extra chromosome responsible for Down syndrome demonstrates.
But autism does not work this way. We know that many of the gene variants contributing to autism are not rare, one-time mutations. Autism results from a combination of genes, hundreds or possibly thousands, and many of them are inherited. These gene variants persistence in the human genome implies one crucial fact: they must serve some useful purpose, some purpose that enhances reproductive success.
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Brain Size And Growth
Large brain size and head circumference, especially in childhood but also adulthood, represent some of the best-substantiated phenotypic correlates of autism . Autism-linked increases in brain size have been shown to involve higher numbers of neurons , a thicker cortex , increased hippocampus volume , increased brain growth rates in early childhood , increased rate of cortical thinning in adolescence , a combination of accelerated expansion in early childhood with accelerated thinning in in later childhood and adolescence , and increased processing of more-local, detailed information .
Faster increase in cortical thickness between ages 6 and 12, followed by faster cortical thickness deceleration between ages 12 and 18 , has been linked with higher intelligence in typically-developing children . These findings provide evidence that trajectories of brain growth rate during middle childhood to adolescence are notably associated with IQ, with an overall pattern of accelerated growth and accelerated pruning that matches trajectories reported in autism, though with different timings of growth in early childhood. Within humans , and among non-human primates species, brain size are also positively correlated with measures of intelligence, an effect that appears to be mediated predominantly by numbers of neurons .
Evolution Of Autism Genes Hints At Their Fundamental Roles In Body
Emily CasanovaResearch assistant professorResearch assistant professor
Listen to this story:
Autism genes are old. Not just old really old. Theyre older than fish, older than insects and even older than ocean sponges. In fact, many autism genes are older than multicellular life itself.
Aside from being extremely old, as my colleagues and I reported in our latest paper in April, these ancient genes are particularly sensitive to mutations1. And when mutations occur, the resulting effects can be profound. The more conserved a gene the more its sequence has stayed constant across species the more likely that mutations anywhere on that gene will have big effects.
People with these mutations often have physical malformations, which occur at higher-than-expected rates2. This suggests that autism genes are involved in orchestrating the development of many parts of the body, not just the brain. Many also function as regulators of gene expression, helping to control the timing of development3,4. These old biological processes are part of lifes tool kit. Autism genes are foundational, developmentally and evolutionarily.
Curiously, ancient autism genes also tend to have a characteristic structure: They are long and many produce large proteins5.
Altogether, these data tell us that autism genes play nuanced, complex and fundamental roles throughout the body.
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The Cloud Behind The Silver Lining
Individuals with autism can create challenges for societies, whether small scale hunter-gatherers or large scale modern societies. Pronounced counter-dominance tactics in hunter-gathers for example may have developed in part to prevent the dominance of those with autistic traits such as rigid rules and a lack of sensitivity to potential emotional consequences of their actions. Thus no matter how much someone is respected in small scale egalitarian groups, their rights to dictate the behaviour of others is heavily constrained by shared action to maintain equality. Indeed Boehm documents a progressive series of sanctions for dominating behaviour from ridicule to ostracism or assassination . Such dynamics have also been recognised in Palaeolithic and Mesolithic contexts . Whilst counter-dominance tactics work in a small scale setting, in modern societies a lack of such intuitively based social sanctions on behaviour may create problems where highly dominant individuals with autism are in positions of power. In this case such individuals may make decisions with emotionally damaging consequences for others which remain unchallenged.
Most individuals with autism are highly moral. However where autism is associated with disorders of motivation , as in the case of autistic psychopathology, a lack of intuitive feeling of others suffering allied with a desire to harm can be a literally lethal combination .
We See It As Essentially A Condition Of Profound Sensitivity
Autism and its evolutionary advantages. Analyzing the multiple functions of stereotypical behavior for students with autism. For this reason, people often refer to autism as autism spectrum disorder . Unlike others, we do not define autism as a disorder or an impairment. Autism is a developmental disorder characterized by difficulties with social interaction and communication, and by restricted and repetitive behavior. The evolutionary perspective in ap® psych is related to the same theory in biology. .a neurophysiological perspective on social cognition and its disruption in autism vittorio gallese produced by the collapse of the others’ intentions evolutionary point of view, may scaffold more. We reviewed different theories on the. An evolutionary psychological theory of the amygdala. This is an amazing answer, and i thank you for sharing your perspective. These links from our past indicate that autism has an evolutionary basis, and has shaped the course of. Evolutionary psychology and the evolution of psychology by daniel kruger. Evolutionary psychology is not a distinct branch of psychology, but rather a theoretical lens that is currently.
Evolutionary perspective`, which has received attention recently in various academic fields, suggests several theories regarding the ultimate causality of autism.
These links from our past indicate that autism has an evolutionary basis, and has shaped the course of.
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Minds From A Stone Age Past
Our modern societies have been said to house stone age minds . That is to say that despite all the influences of modern culture our hard wired neurological make-up, instinctive responses and emotional capacities evolved in the vast depths of time which make up our evolutionary past. Much of what makes us human thus rests on the nature of societies in the depths of prehistory thousands or even millions of years ago.
Looking back on the archaeological record of the early stone age there is much to be proud of in our ancestry. Not only our remarkable intelligence but also our deep capacities to care about others and work together for a common good come from evolutionary selection on early humans throughout millions of years of the stone age. As far back as 1.6 million years ago we have archaeological evidence from survival of illnesses and trauma that those who were ill were looked after by others, and by the time of Neanderthals extensive care of the ill, infirm and elderly was common, see . From at least one million years ago we see evidence for widespread collaboration in hunting, in sharing food and in looking after increasingly vulnerable young. Stone age societies, much as recent hunter-gatherers such as the Selknam of Tierra del Fuego , lived in small groups who cared deeply about each other, and worked together to survive.
Figure 1.
Human Pluripotent Stem Cell Models Of Asd
Human pluripotent stem cells , including human embryonic stem cells and human iPSCs, have the capacity to differentiate into unlimited supplies of brain cells and therefore have tremendous potential for modeling ASD . To date, hPSC studies of ASD have focused largely on variants that disrupt protein-coding genes, which have revealed a wide range of synaptic phenotypes . Synaptic phenotyping in iPSC models of ASD has focused primarily on excitatory synaptic function, which is impaired in some models and increased in others . The majority of iPSC ASD models with synaptic phenotypes report decreased connectivity, and for some genes, the underlying mechanisms have been determined. Physiological decreases in synaptic function can result from fewer excitatory synapses , impairments in neurotransmitter release , or hypofunction of excitatory NMDA receptors . Conversely, some other genetic models of ASD show increased synaptic function via increased synapse numbers or hyperfunction of NMDA receptors . Together, these findings support the notion that increases or decreases in synaptic activity outside of the range that is typical of unaffected individuals may impair sensory processing and social interactions, thereby contributing to ASD development .
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Transcriptional Regulatory Elements In Asd
WGS studies have revealed extensive evidence for ASD-associated non-coding variants in transcriptional regulatory elements like promoters and enhancers, which are functionally annotated based on transcriptomics data and chromatin state analyses . WGS studies reported that non-coding variants were enriched in conserved enhancers that are accessible in the fetal brain or predicted to regulate ASD genes . WGS has also detected de novo ASD-associated variants in distal promoters , which had a significant association with transcription factor binding sites . Rare recurrent variants were found disrupting predicted promoters for DLG2 and NR3C2, which have both been implicated in brain function or neurodevelopment .
The Architecture And Correlates Of Human Intelligence
Figure 1. The VPR model of intelligence. Under this model, the higher-level architecture of human intelligence, as indicated by diverse mental-ability tasks, involves one general factor, g, and three mid-level factors, Verbal, Perceptual, and image Rotation, that reflect variation among individuals in large-scale neural structure and processing. Adapted from Johnson et al. .
Figure 2. Two orthogonal dimensions of intelligence, which emerge after the general factor g is statistically removed. Poles of each of the two dimensions demonstrate inverse associations with one another, indicative of neurally-based cognitive trade-offs. The psychotic-affective spectrum includes mainly schizophrenia, bipolar disorder, depression, and borderline personality disorder. Adapted from Johnson et al. .
Figure 3. Brain regions, and temporal stages, representing the P-FIT model of intelligence. Postulated alterations in autism, compared to control individuals, are shown along the periphery, and described in the text. Adapted from Colom et al. .
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Does Autism Hold The Key To What Makes Humans Special
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THE PATTERN SEEKERSHow Autism Drives Human InventionBy Simon Baron-Cohen
At the end of the 20th century, scholars of human evolution proposed a thrilling idea: Humans were special and distinct from all other animals because of a sudden transformational change that occurred around 35,000 years ago. For millions of years our ancestors had trudged through existence with the same simple tool kit, yet in that special moment, there was a flowering of symbolism, of art, of complicated tool use. This was when the modern human mind was born. You could see its traces in the archaeological record.
The extraordinary cultural shift must have been caused by an equally dramatic biological change, or so it was thought. The problem was that Homo sapiens had been physically the same for around 250,000 years. How could we have changed so utterly but left no sign of it in our bones? Perhaps the human brain had stayed the same size but undergone a structural re-organization. Maybe we evolved new software to generate syntax. Possibly this was when words were first spoken. Or a single, fortuitous genetic mutation had occurred, out of which all of human civilization eventually flowed.