Autism and the DSM-5

19 December 2012

There has been a lot of talk in the media about the forthcoming DSM-5 and the diagnosis of Autism.  The DSM-5 is the Fifth Edition of the Diagnostic and Statistical Manual used by Doctors to make diagnoses pertaining to Autism and other behavioral and mental health disorders.  There are in fact two major changes in this newest edition regarding Autism.  The first has to do with changes to the name of the diagnosis.  The second has to do with the actual diagnostic criteria used to make a diagnosis.


Currently, when presented with a child who exhibits some characteristics of Autism, Doctors have to determine whether or not the child exhibits a sufficient array of clinically significant symptoms to warrant a diagnosis.  This process requires the clinician to rule out other disorders that may instead be causing the problematic symptoms.  The clinician also has to make a differential diagnosis to determine which of the Pervasive Developmental Disorders best describes the child.  Many professionals, me included, believe that the dividing lines between the various forms of Autism are difficult to distinguish.  The new DSM does away with this problem by eliminating the different labels (Autistic Disorder, Asperger’s Disorder, PDD-NOS, Childhood Disintegrative Disorder) and instead puts in place a more general term – Autism Spectrum Disorder (ASD).  Many researchers and clinicians agree that this change is warranted.


When the DSM-5 is published in May of 2013, children who previously would have been diagnosed with Autistic Disorder, Asperger’s Disorder, or PDD-NOS, will be given the new diagnosis – Autistic Spectrum Disorder (ASD).  A differentiation will then be made by indicating the degree of symptom severity.  Specifically, those with more classical Autism will be diagnosed with ASD-Severe.  At the other end of the spectrum, children diagnosed with Pervasive Developmental Disorder – Not Otherwise Specified (PDD-NOS) will likely get an ASD-Mild designation.  Those with Asperger’s may fall anywhere from ASD-Severe to ASD-Mild, depending on the degree of impairment.  Many with Asperger’s will likely fall in the Moderate range.  To be clear however, Classical Autism may span Severe to Mild ASD while PDD-NOS will likely span Moderate to Mild ASD.  Again, the severity designation depends on the number and severity of symptoms present.  If your child already carries a diagnosis, little will change, except perhaps how professionals refer to the disorder itself.   Your child will be referred to as being on the Autistic Spectrum.


The second change involves a modification of the Diagnostic Criterion used to provide a diagnosis.  When making a diagnosis, a clinician such as myself, has to have evidence of a sufficient array of behaviors listed in the DSM in order to provide a diagnosis.  The behaviors commonly associated with Autism make up the list of Diagnostic Criterion in the manual.  The new DSM includes an update of the behaviors used as these criteria.  It defines ASD by two sets of core features, namely: 1) impaired social communication and social interactions; and 2) restricted and repetitive behavior and interests. It more appropriately reorganizes the symptoms in these domains and adds sensory interests and sensory aversions to the list.


The new version is touted as an improvement because it adds to and reorganizes the diagnostic criterion so that they better address the needs of people with ASD across all developmental levels and ages.  It also includes improvements to better address the atypical symptom presentation of girls.  The goal of DSM-5 is to apply what is detailed in the scientific literature so as to add precision and validity to the diagnostic process.


As with any change, there have been some concerns expressed in the media.  Perhaps the most frequently heard concern is the fear that those at the mildest end of the spectrum with strong cognitive capabilities will no longer qualify for the diagnosis and thus may lose services.  Advocacy groups such as Autism Speaks have been actively engaging in this reorganization process and the American Psychiatric Association (the publisher of the DSM) has made statements aimed to calm the concerns.  They suggest that clinical judgment remains a crucial piece of the diagnostic process and that the new criteria are designed to be completely inclusive of those diagnosed using the current DSM-IV.  The research released by the American Psychiatric Association shows improved reliability and validity of diagnoses using the DSM-5 and strong inclusiveness of those already diagnosed using the DSM-IV.  I have seen the proposed diagnostic criterion and upon review I did not have any serious concerns with regard to how it will affect my ability to make diagnoses.


The bottom line is that for most parents, there will be no appreciable change other than how we refer to your child.  In anticipation of this change we have already been using the phrase Autism Spectrum Disorder or “on the spectrum” for quite some time now.  Diagnoses in the near term will still be made using the current DSM-IV, and thus, we will still be using the terms Autistic Disorder, Asperger’s Disorder, and PDD-NOS.   It is advisable for clinicians/diagnosticians to commence using both sets of terminology so as to minimize confusion in the future.  Sharing a document such as this one with the parents of the newly diagnosed is also advised.

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Have you ever heard someone make an argument that leaves you shaking your head in disbelief?  Does it seem to you like some people are coming from a completely different reality than your own?  If so, then this blog is for you.  I have spent the last year trying to develop an understanding of the common thought patterns that drive the acrimonious spirit of our social and political dialogue.  I am continually amazed by what I hear coming from seemingly informed people.  I have assumed that some folks are either deluded, disingenuous, or downright ignorant.  There is yet another possibility here, including the reality that different moral schema or belief systems may be driving their thinking.  And if this is the case, how do these divergent processes come to be?  I  have learned a lot through this exploration and feel compelled do provide a recap of the posts I have made.  I want to share with you those posts that have gathered the most traction and some that I believe warrant a bit more attention.


Over the past year I have posted 52 articles often dealing with Erroneous Thought Processes, Intuitive Thinking, and Rational Thought.  Additionally, I have explored the down stream implications of these processes with regard to politics, morality, religion, parenting, memory, willpower, and general perception.  I have attempted to be evidenced-based and objective in this process – striving to avoid the very trappings of confirmation bias and the erroneous processes that I am trying to understand.   As it turns out, the brain is very complicated: and although it is the single most amazing system known to human kind, it can and does lead us astray in very surprising and alarming ways.


As for this blog, the top ten posts, based on the shear number of hits, are as follows:

  1. Attribution Error
  2. Nonmoral Nature, It is what it is.
  3. Multitasking: The Illusion of Efficacy
  4. Moral Instinct
  5. Pareidolia
  6. IAT: Questions of Reliability
  7. Are You a Hedgehog or a Fox?
  8. What Plato, Descartes, and Kant Got Wrong: Reason Does not Rule
  9. Illusion of Punditry
  10. Emotion vs.Reason: And the winner is?

What started out as ramblings from a curious guy in a remote corner of New York State ended up being read by folks from all over the planet.  It has been a difficult process at times, consuming huge amounts of time, but it has also been exhilarating and deeply fulfilling.


I have been heavily influenced by several scientists and authors in this exploration.  Of particular importance have been Steven Pinker, Daniel Simons, Christopher Chabris, Jonah Lehrer, Bruce Hood, Carl Sagan, and Malcolm Gladwell.  Exploring the combined works of these men has been full of twists and turns that in some cases necessitated deep re-evaluation of long held beliefs.  Holding myself to important standards – valuing evidence over ideology – has been an important and guiding theme.


Several important concepts have floated to the top as I poked through the diverse literature pertaining to thought processes. Of critical importance has been the realization that what we have, when it comes to our thought processes, is a highly developed yet deeply flawed system that has been shaped by natural selection over millions of years of evolution.  Also important has been my increased understanding of the importance of genes, the basic element of selective pressures, as they play out in morality and political/religious beliefs.  These issues are covered in the top ten posts listed above.


There are other worthy posts that did not garner as much attention as those listed above.  Some of my other favorites included a review of Steven Pinker’s article in the New York Times (also titled Moral Instinct,) a look at Jonathon Haidt’s Moral Foundations Theory in Political Divide, as well as the tricks of Retail Mind Manipulation and the Illusion of Attention.  This latter post and my series on Vaccines and Autism (Part 1, Part 2, Part 3) were perhaps the most important of the lot.  Having the content of these become general knowledge would make the world a safer place.


The evolution of understanding regarding the power and importance of Intuitive relative to Rational Thinking was humbling at times and Daniel Simons’ and Christopher Chabris’ book, The Invisible Gorilla, certainly provided a mind opening experience.  Hey, our intuitive capabilities are incredible (as illustrated by Gladwell in Blink & Lehrer in How We Decide) but the downfalls are amazingly humbling.  I’ve covered other topics such as  happiness, superstition, placebos, and the debate over human nature.


The human brain, no matter how remarkable, is flawed in two fundamental ways.  First, the proclivities toward patternicity (pareidolia), hyperactive agency detection, and superstition, although once adaptive mechanisms, now lead to many errors of thought.  Since the age of enlightenment, when human kind developed the scientific method, we have exponentially expanded our knowledge base regarding the workings of the world and the universe.  These leaps of knowledge have rendered those error prone proclivities unessential for survival.  Regardless, they have remained a dominant cognitive force.  Although our intuition and rapid cognitions have sustained us, and in some ways still do, the everyday illusions impede us in important ways.


Secondly, we are prone to a multitude of cognitive biases that diminish and narrow our capacity to truly understand the world. Time after time I have written of the dangers of ideology with regard to its capacity to put blind-folds on adherents.  Often the blind- folds are absolutely essential to sustain the ideology.  And this is dangerous when truths and facts are denied or innocents are subjugated or brutalized.  As I discussed in Spinoza’s Conjecture“We all look at the world through our personal lenses of experience.  Our experiences shape our understanding of the world, and ultimately our understanding of [it], then filters what we take in.  The end result is that we may reject or ignore new and important information simply because it does not conform to our previously held beliefs.


Because of our genetically inscribed tendencies toward mysticism and gullibility, we must make extra effort in order to find truth. As Dr. Steven Novella once wrote:

“We must realize that the default mode of human psychology is to grab onto comforting beliefs for purely emotional reasons, and then justify those beliefs to ourselves with post-hoc rationalizations. It takes effort to rise above this tendency, to step back from our beliefs and our emotional connection to conclusions and focus on the process.”

We must therefore be humble with regard to beliefs and be willing to accept that we are vulnerable to error prone influences outside our awareness.  Recognition and acceptance of these proclivities are important first steps.   Are you ready to move forward?  How do you think?


Over the last two weeks I’ve dealt with the issue of vaccines as they pertain to Autism. I first dealt with the back story and then addressed why such an illusion of cause has persisted despite the efforts of the scientific and medical communities. Although I have made reference to some of the data, I thought it would be prudent to put forward some particularly relevant facts and statistics.


First, I would like to note the progress mankind has made with regard to average life span and give credit where credit is due. Carl Sagan, in his excellent book, The Demon-Haunted World, addressed this very issue indicating that in pre-agricultural times, 10,000 years ago, human life expectancy was about 20-30 years. That expectancy persisted throughout the rise and fall of the Greek and Roman empires right through Medieval times. Not until the late 19th century did it rise to 40 years. In 1915 it was estimated to be 50 and then as high as 60 by 1930. It rose to 70 in about 1955 and is currently around 80 for individuals living in developed countries.


So what can we attribute this growth in life expectancy to? The answer is clear. Along with advancements in public sanitation (clean water, flush toilets) and vast improvements in nutrition, science has contributed the germ theory of disease and huge advancements in medical care and medical technology. Of particular importance has been our increased capacity to understand and prevent infectious diseases. Understanding how diseases spread has been important in minimizing the spread of illnesses like TB and it continues to be important with regard to HIV; however, another huge variable has been the introduction of immunizations.


Not all that long ago, infectious diseases were among the top causes of death for humans in developed nations. And this is still the case in many low income countries. According to World Health Organization statistics, six of the top ten causes of death in low income nations include infectious diseases (respiratory infections 11.2%, Diarrheal diseases, 6.9%, HIV/AIDS 5.7%, TB 3.5%, neonatal infections 3.4%, and Malaria 3.3%). Whereas in high-income countries, heart disease, cerebrovascular disease, and cancer reign supreme. The only infectious disease to make the top 10 in high-income countries is lower respiratory infections (3.8%). Although heart disease, strokes, and cancer afflict the 3rd world, the proportion of deaths attributable to infectious diseases dominates. This discrepancy is essentially due to publicly managed vaccine and infection control programs affordable only to relatively wealthy industrialized nations.


If you look back in time at US morbidity and mortality statistics (Roush, Murphy, & the Vaccine-Preventable Disease Table Working Group, 2007) pre- and post-mandated vaccines, the numbers are staggering. The peak annual death rates for diseases like diphtheria was 3065 (1936), measles 552 (1958), mumps 50 (1964), rubella 24 (1968), pertussis 7518 (1934), polio (paralytic) 3145 (1952), and smallpox 2510 (1902). The peak morbidity rate for diphtheria was 30,508 (1938), measles 763,094 (1958), mumps 212,932 (1964), rubella 488,796 (1968), pertussis 265,209 (1934), Polio (paralytic) 21,269 (1952), and smallpox 2510 (1902). In 2004 (the post mandated vaccine era) there were no (zero) deaths in the US attributable to diphtheria, measles, mumps, paralytic polio, rubella, and smallpox. Pertussis persists, having killed 27 people in 2004, afflicting over 15,000 in 2006. Regardless, in the US, our vaccine schedules have essentially eradicated infectious diseases that previously took thousands of children’s lives every year. There has been more than a 92% decline in morbidity and a 99% or greater reduction in deaths attributed to preventable infectious diseases targeted since 1980 by the current vaccine schedule. Endemic transmission of measles, rubella, and the poliovirus have also been eliminated and smallpox has been eradicated worldwide. This is no small accomplishment. One must keep in mind that one who fails to learn from history is doomed to repeat it (Crislip paraphrasing Santayana).


The objections to vaccines put forth by the anti-vaccine folks have morphed over time. The initial notions included the presence of mercury (thimerosal) in the vaccines and the vilification of the MMR vaccine itself. Both of these notions have been debunked. The new themes include too many too soon and the presence of other toxins in the vaccines.


In my previous post, The Illusion of Cause – Vaccines and Autism, I addressed the innate human propensity to draw causal relationships between vaccines and Autism. I noted that despite the removal of thimerosal from routine childhood vaccines, the numbers of incidences of Autism continues to rise. And I discussed the fact that thimerosal contains ethyl-mercury which poses far less risk than the more dangerous fat soluble methyl-mercury. Eating a six ounce chunk of tuna exposes one to 8959 micrograms of methyl-mercury while the maximum cumulative exposure to mercury through the first six months of life (before the removal of thimerosal) was around 187.5 micrograms of ethyl-mercury (Crislip, 2010). The research has been clear: there is no plausible association between mercury toxicity or even other heavy metal exposure and Autism (Science in Autism Treatment, 2009). In particular, a study published in 2007 in Research in Autism Spectrum Disorders by Williams, Hersh, Allard, and Sears found no significant difference in the levels of mercury detected in hair samples between children diagnosed with Autism and their un-afflicted siblings. Regardless, thimerosal has been removed from routine childhood vaccines (except some influenza and some tetanus multi-dose vials) not due to safety concerns but to reduce non-compliance issues associated with unwarranted fear. Thimerosal is a non-issue.


With regards to the MMR vaccine – I previously discussed how Andrew Wakefield misrepresented his personal conflicts of interest and intentionally manipulated the data to support his contention that MMR causes Autism. Study after study, many of which were large scale epidemiological studies, failed to replicate Wakefield’s findings. And what is even more interesting is that some studies suggest that the MMR vaccine is actually associated with decreased incidences of Autism in recipients versus non-recipients (Mrozek-Budzyn, D., Kieltyka, A., and Majewska, R. 2010). This is likely background noise and may not pan out in other studies, but…….. In Jackson County, Oregon 15% of the children have not been vaccinated. Within Jackson County, in the city of Ashland, 25% of the children are not vaccinated. The rate of educational diagnoses of Autism in Ashland is 1.1% – which is the highest rate in the county and above the state average (Crislip, 2010). So the population where there is the lowest rate of vaccination also includes the highest rate of Autism diagnoses. One has to be careful not to fall victim to the illusion of cause with this data.


Too Many Too Soon is the new mantra, railed by the anti-vaccine set: but this argument is easily assuaged by gaining a better understanding of the microbiome. Mark Crislip, MD, an immunologist, effectively puts this issue into perspective in his podcast The Vaccine Pseudo Controversy. Crislip notes that for every human cell in the human body there are 10 bacteria cells along for the ride. We are essentially a host organism for 100 billion bacteria representing several thousand species. Although a human baby is born free of such organisms, by the end of the first year of life, a typical baby has been exposed to perhaps billions of such organisms. Many of these bacteria are essential for our survival, but many are in fact pathogens kept at bay by the immune system. Extremely conservative estimates suggest that on average, a child is exposed to at least one pathogen each day just as a function of living. That being said, the vaccine schedule represents 0.694% of the antigen exposure of a six year old. As Dr. Crislip is fond of saying, the vaccines constitute a mere drop in the bucket in terms of the total number of pathogens endured just as a function of living day to day. Seriously, have you ever been around a baby? They crawl around on the ground and mouth everything they can get their hands on. A drop in the bucket indeed. Dr. Crislip notes that “the only thing a delay in vaccination does is increase the time the child is vulnerable to infections” and, I would add, weaken herd immunity. As for evidence, consider a recent study published in Pediatrics by Michael J. Smith, MD and Charles R. Woods, MD, entitled On-Time Vaccine Receipt in the First Year Does Not Adversely Affect Neuropsychological Outcomes. An excerpt of the abstract reads as follows:


OBJECTIVES: To determine whether children who received recommended vaccines on time during the first year of life had different neuropsychological outcomes at 7 to 10 years of age as compared with children with delayed receipt or nonreceipt of these vaccines.
METHODS: Publicly available data, including age at vaccination, from a previous Vaccine Safety Datalink study of thimerosal exposure and 42 neuropsychological outcomes were analyzed. Secondary analyses were performed on a subset of children with the highest and lowest vaccine exposures during the first 7 months of life.
RESULTS: Timely vaccination was associated with better performance on 12 outcomes in univariate testing and remained associated with better performance for 2 outcomes in multivariable analyses. No statistically significant differences favored delayed receipt. In secondary analyses, children with the greatest vaccine exposure during the first 7 months of life performed better than children with the least vaccine exposure on 15 outcomes in univariate testing; these differences did not persist in multivariable analyses. No statistically significant differences favored the less vaccinated children.
CONCLUSIONS: Timely vaccination during infancy has no adverse effect on neuropsychological outcomes 7 to 10 years later. These data may reassure parents who are concerned that children receive too many vaccines too soon. Pediatrics 2010;125:1134–1141


And then there is the contention that there are toxins in the vaccines. Well this is undeniably true. The Center for Disease Control makes known the additives for each vaccine. The list may initially seem foreboding, but the CDC and Dr. Crislip, as well as others consulted who posses far more expertise than I, attempt to assure us that these additives perform important functions and pose no notable risk. The CDC notes: “Chemicals commonly used in the production of vaccines include a suspending fluid (sterile water, saline, or fluids containing protein); preservatives and stabilizers (for example, albumin, phenols, and glycine); and adjuvants or enhancers that help improve the vaccine’s effectiveness. Vaccines also may contain very small amounts of the culture material used to grow the virus or bacteria used in the vaccine, such as chicken egg protein.


The CDC notes that Common substances found in vaccines include:

  • Aluminum gels or salts of aluminum which are added as adjuvants to help the vaccine stimulate a better response to the vaccine. Adjuvants help promote an earlier, more potent response, and more persistent immune response to the vaccine.
  • Formaldehyde is used to inactivate bacterial products for toxoid vaccines, (these are vaccines that use an inactive bacterial toxin to produce immunity.) It is also used to kill unwanted viruses and bacteria that might contaminate the vaccine during production.
  • Monosodium glutamate (MSG) and 2-phenoxy-ethanol which are used as stabilizers in a few vaccines to help the vaccine remain unchanged when the vaccine is exposed to heat, light, acidity, or humidity.
  • Thimerosal is a mercury-containing preservative that is added to vials of vaccine that contain more than one dose to prevent contamination and growth of potentially harmful bacteria.


A little more knowledge is helpful. Did you know, for example, that “the average person produces about 1.5 ounces of formaldehyde each day as a part of normal metabolic processes[?]” (Crislip, 2010). It’s true. And as a result, there is a low steady state of formaldehyde in human blood at a concentration of 1 to 2 parts-per-million. The concentration of this additive in vaccines is actually at a lower level than is naturally occurring in your blood. Dr. Crislip notes that by far, the deadliest additive in vaccines is dihydrogen monoxide – which is responsible for nine deaths a day in the US. Otherwise, if you accept the dose-response effect of chemicals and the microscopic doses of the additives in vaccines, you will rest assured that vaccines are safe and serve a very important life saving role in our civilization. The bottom line comes down to belief systems. If you believe something so fully that you are unwilling to put a skeptical eye on it and reject it, if the evidence does not support it, then you are rejecting reality in support of unsubstantiated ideology. Always be wary of unsubstantiated ideology! Oh and the dihydrogen monoxide – that’s water (H2O).




Association for Science in Autism Treatment. (2009). Autism & Vaccines: The Evidence to Date. Vol. 6., No. 1


Center for Disease Control. Basics and Common Questions: Ingredients of Vaccines – Fact Sheet.


Crislip, M. (2010). The Vaccine Pseudo Controversy. Quackcast # 45.


Mrozek-Budzyn, D., Kieltyka, A., and Majewska, R. (2010).Lack of Association Between Measles-Mumps-Rubella Vaccination and Autism in Children: A Case-Control Study.Pediatric Infectious Disease Journal. 29(5):397-400.


Roush, S. W., Murphy, T. V., & the Vaccine-Preventable Disease Table Working Group. (2007). Historical Comparisons of Morbidity and Mortality for Vaccine-Preventable Diseases in the United States. JAMA. 298(18):2155-2163 (doi:10.1001/jama.298.18.2155)


Sagan, C. (1996). The Demon Haunted Word. The Random House Publishing Group: New York


Smith, M. J. and Woods, C. R. (2010). On-time Vaccine Receipt in the First Year Does Not Adversely Affect Neuropsychological Outcomes. Pediatrics published online May 24, 2010; DOI: 10.1542/peds.2009-2489


Williams, P. G., Hersh, J. H., Allard, A., and Sears, L. L. A controlled study of mercury levels in hair samples of children with autism as compared to their typically developing siblings.” Research in Autism Spectrum Disorders. 16 May 2007, Volume 2, Issue 1: 170-175.


World Health Organization. (2004). The 10 leading causes of death by broad income group. Fact Sheet No. 310.


There are many well intentioned folks out there who believe that childhood vaccinations cause Autism. Last week I covered the origins of this belief system as well as its subsequent debunking in Vaccines and Autism. Despite the conclusive data that clearly establishes no causal link between vaccines and Autism, the belief lives on. Why is this? Why do smart people fall prey to such illusions? Chabris and Simons contend in their book, The Invisible Gorilla, that we fall prey to such myths because of the Illusion of Cause. Michael Shermer (2000), in his book, How We Believe, eloquently describes our brains as a Belief Engine. Underlying this apt metaphor is the notion that “Humans evolved to be skilled pattern seeking creatures. Those who were best at finding patterns (standing upwind of game animals is bad for the hunt, cow manure is good for the crops) left behind the most offspring. We are their descendants.” (Shermer, p. 38). Chabris and Simons note that this refined ability “serves us well, enabling us to draw conclusions in seconds (or milliseconds) that would take minutes or hours if we had to rely on laborious logical calculations.” (p. 154). However, it is important to understand that we are all prone to drawing erroneous connections between stimuli in the environment and notable outcomes. Shermer further contends that “The problem in seeking and finding patterns is knowing which ones are meaningful and which ones are not.


From an evolutionary perspective, we have thrived in part, as a result of our tendency to infer cause or agency regardless of the reality of threat. For example, those who assumed that rustling in the bushes was a tiger (when it was just wind) were more likely to take precautions and thus less likely, in general, to succumb to predation. Those who were inclined to ignore such stimuli were more likely to later get eaten when in fact the rustling was a hungry predator. Clearly from a survival perspective, it is best to infer agency and run away rather than become lunch meat. The problem that Shermer refers to regarding this system is that we are subsequently inclined toward mystical and superstitious beliefs: giving agency to unworthy stimuli or drawing causal connections that do not exist. Dr. Steven Novella, a neurologist, in his blog post entitled Hyperactive Agency Detection notes that humans vary in the degree to which they assign agency. Some of us have Hyperactive Agency Detection Devices (HADD) and as such, are more prone to superstitious thinking, conspiratorial thinking, and more mystical thinking. It is important to understand as Shermer (2000) makes clear:


“The Belief Engine is real. It is normal. It is in all of us. Stuart Vyse [a research psychologist] shows for example, that superstition is not a form of psychopathology or abnormal behavior; it is not limited to traditional cultures; it is not restricted to race, religion, or nationality; nor is it only a product of people of low intelligence or lacking education. …all humans possess it because it is part of our nature, built into our neuronal mainframe.” (p. 47).


We all are inclined to detect patterns where there are none. Shermer refers to this tendency as patternicity. It is also called pareidolia. I’ve previously discussed this innate tendency noting that “Our brains do not tolerate vague or obscure stimuli very well. We have an innate tendency to perceive clear and distinct images within such extemporaneous stimuli.” It is precisely what leads us to see familiar and improbable shapes in puffy cumulus clouds or the Virgin Mary in a toasted cheese sandwich. Although this tendency can be fun, it can also lead to faulty and sometimes dangerous conclusions. And what is even worse is that when we hold a belief, we are even more prone to perceive patterns that are consistent with or confirm that belief. We are all prone to Confirmation Bias – an inclination to take in, and accept as true, information that supports our belief systems and miss, ignore, or discount information that runs contrary to our beliefs.


Patternicity and confirmation bias alone are not the only factors that contribute to the illusion of cause. There are at least two other equally salient intuitive inclinations that lead us astray. First, we tend to infer causation based on correlation. And second, the appeal of chronology, or the coincidence of timing, also leads us toward drawing such causal connections (Chabris & Simons, 2010).


A fundamental rule in science and statistics is that correlation does not infer causation. Just because two events occur in close temporal proximity, does not mean that one leads to the other. Chabris and Simons note that this rule is in place because our brains automatically – intuitively – draw causal associations, without any rational thought. We know that causation leads to correlation – but it is erroneous to assume that the opposite is true. Just because A and B occur together does not mean A causes B or vice-versa. There may be a third factor, C, that is responsible for both A and B. Chabris and Simons use ice cream consumption and drownings as an example. There is a sizable positive correlation between these two variables (as ice cream consumption goes up so do the incidences of drowning), but it would be silly to assume that ice cream consumption causes drowning, or that increases in the number of drownings causes increases in ice cream consumption. Obviously, a third factor, summer heat, leads to both more ice cream consumption and more swimming. With more swimming behavior there are more incidents of drowning.


Likewise, with vaccines and Autism, although there may be a correlation between the two (increases in the number of children vaccinated and increases in the number of Autism diagnoses), it is incidental, simply a coincidental relationship. But given our proclivity to draw inferences based on correlation, it is easy to see why people would be mislead by this relationship.


Add to this the chronology of the provision of the MMR vaccine (recommended between 12 and 18 months), and the typical time at which the most prevalent symptoms of Autism become evident (18-24 months), people are bound to infer causation. Given the fact that millions of children are vaccinated each year, there are bound to be examples of tight chronology.


So what is at work here are hyperactive agency detection (or overzealous patternicity), an inherent disposition to infer causality from correlation, and a propensity to “interpret events that happened earlier as the causes of events that happened or appeared to happen later” (Chabris & Simons, 2010, p. 184).  Additionally, you have a doctor like Andrew Wakefield misrepresenting data in such a way to solidify plausibility and celebrities like Jenny McCarthy using powerful anecdotes to convince others of the perceived link. And anecdotes are powerful indeed. “..[W]e naturally generalize from one example to the population as a whole, and our memories for such inferences are inherently sticky. Individual examples lodge in our minds, but statistics and averages do not. And it makes sense that anecdotes are compelling to us. Our brains evolved under conditions in which the only evidence available to us was what we experienced ourselves and what we heard from trusted others. Our ancestors lacked access to huge data sets, statistics, and experimental methods. By necessity, we learned from specific examples…” (Chabris & Simons, 2010, pp. 177-178).  When an emotional mother (Jenny McCarthy) is given a very popular stage (The Oprah Winfrey Show) and tells a compelling story, people buy it – intuitively – regardless of the veracity of the story. And when we empathize with others, particularly those in pain, we tend to become even less critical of the message conveyed (Chabris & Simons, 2010). These authors add that “Even in the face of overwhelming scientific evidence and statistics culled from studies of hundreds of thousands of people, that one personalized case carries undue influence” (p.178).


Although the efficacy of science is unquestionable, in terms of answering questions like the veracity of the relationship between vaccines and Autism, it appears that many people are incapable of accepting the reality of scientific inquiry (Chabris & Simons, 2010). Acceptance necessitates the arduous application of reason and the rejection of the influences rendered by the intuitive portion of our brain. This is harder than one might think. Again, it comes down to evolution. Although the ability to infer cause is a relatively recent development, we hominids are actually pretty good at it. And perhaps, in cases such as this one, we are too proficient for our own good (Chabris & Simons, 2010).




Center for Disease Control. (2009). Recommended Immunization Schedule for Persons Aged 0 Through 6 Years.


Chabris, C. F., & Simons, D. J. (2010). The Invisible Gorilla. Random House: New York.


Novella, S. (2010). Hyperactive Agency Detection. NeuroLogica Blog.


Shermer, M. (2000). How We Believe. W.H. Freeman / Henry Holt and Company: New York.


Vaccines and Autism

13 August 2010

It is hard to imagine anything more precious than one’s newborn child. Part of the joy of raising a child is the corresponding hope one has for the future. Don’t we all wish for our children a life less fraught with the angst and struggles we ourselves endured? One of the less pleasant aspects of my job has the effect, at least temporarily, of robbing parents of that hope. This erosion occurs in the parent’s mind and heart as a consequence of a diagnosis I often have to provide. I am a psychologist employed in part to provide diagnostic evaluations of preschool age children suspected of having Autism. My intention is never to crush hope, instead it is to get the child on the right therapeutic path as early as possible in order to sustain as much hope as possible. However, uttering the word AUTISM in reference to one’s child constitutes a serious and devastating emotional blow.


Many parents come to my office very aware of their child’s challenges and the subsequent implications. They love their child, accept him as he is, and just want to do whatever they can to make his life better. Others come still steeped in hope that their child’s challenges are just a phase or believing that she is just fine. Regardless, most of them report that they suspected difficulties very early in the child’s development. For example, many note a lack of smiles, chronic agitation and difficulty soothing their child. Some children had not been calmed by being held or may have even resisted it. Some other children I see develop quite typically. They smile, giggle, rejoice at being held, coo and babble, and ultimately start to use a few words with communicative intent. The parents of this latter and rather rare subset, then watch in dismay as their child withdraws, often losing both functional communication and interest in other children.


The timing of this developmental back-slide most often occurs at around 18 months of age. This regression happens to coincide with the recommended timing of the provision of the Measles-Mumps-Rubella (MMR) vaccine. This temporal chronology is important as it has lead, in part, to a belief that the vaccine itself is responsible for the development of Autism. What these parents must experience at this time, I can only imagine, is a horrible combination of confusion and grief. They have had their hopes encouraged and reinforced only to have them vanquished. And it is human nature, under such circumstances, to look for a direct cause. It makes perfect sense that parents would, given the chronicity of events in some cases, suspect the MMR vaccine as the cause of their child’s regression.


During my occasional community talks on Autism, I often am asked about the alleged connection between vaccines and Autism. The coincidental temporal relationship between the provision of the MMR vaccine and this developmental decay leads to what Chabris and Simons in The Invisible Gorilla refer to as the Illusion of Cause. Chabris and Simons discuss how “chronologies or mere sequences of happenings” lead to the inference “that earlier events must have caused the later ones.” (2010, p. 165). By default, as a result of evolution, our brains automatically infer causal explanations based on temporal associations (Chabris & Simons, 2010).


At nearly every talk I give, there is someone in the audience who is convinced that their child (or a relative) is a victim of the MMR vaccine. Their compelling anecdotes are very difficult to refute or discuss. I find that the application of reason, or data, or both, misses the mark and comes off as being cold and insensitive.


For such causal relationships to endure and spread they often need some confirmation of the effect by an “expert.” This is where the story of Dr. Andrew Wakefield comes into play. Wakefield, a GI Surgeon from the UK published a paper in the prestigious UK medical journal, The Lancet, alleging a relationship between the MMR vaccine and the development of Autism. His “expert” opinion offered legitimacy to already brewing suspicions backed by the perceived correlates of increases in both vaccination and Autism rates, as well as the apparent chronology between the timing of the vaccines and the onset of Autism. Wakefield provided credibility and sufficient plausibility: and as a result, the news of the alleged relationship gained traction.


But hold on! There were major flaws with Wakefield’s study that were not initially detected by The Lancet’s peer review panel. First of all, Wakefield was hired and funded by a personal injury attorney who commissioned him to prove that the MMR vaccine had harmed his clients (caused Autism). His study was not designed to test a hypothesis: it was carried out with the specific objective of positively establishing a link between Autism and provision of the MMR vaccine. From the outset the study was a ruse, disguised as science.


Just this year (2010), 12 years after the initial publication of Wakefield’s infamous study, The Lancet retracted it and Dr. Wakefield has been stripped of his privilege to practice medicine in the UK. Problems however, surfaced years ago: as early as 2004, when 10 of 13 co-authors retracted their support of a causal link. In 2005 it was alleged that Wakefield had fabricated data – in fact, some of the afflicted children used to establish the causal link had never actually received the MMR vaccine!


Since the initial publication of this study, hundreds of millions of dollars have been spent investigating the purported relationship between vaccines and Autism. Despite extensive large scale epidemiological studies, there have been no replications of Wakefield’s findings. Children who had not been vaccinated developed Autism at the same rate as those who had received the MMR. There is no relationship between the MMR vaccine and the development of Autism. As a result of Wakefield’s greed, hundreds of millions of dollars have been wasted. Those dollars could have been devoted to more legitimate pursuits, and that is not the worst of it. I will get to the real costs in a bit.


Another aspect of the history of this controversy is associated with the use of thimerosal as a preservative in vaccines. This notion, which has also been debunked, gained plausibility because thimerosal contains mercury, a known neurotoxin. You may ask: “Why on earth would a neurotoxin be used in vaccines?” Researchers have clearly established that thimerosal poses no credible threat to humans at the dosage levels used in vaccines. However, given the perceived threat, Thimerosal is no longer used as a preservative in routine childhood vaccinations. In fact, the last doses using this preservative were produced in 1999 and expired in 2001. Regardless, the prevalence of autism seems to be rising.


It is important to understand that mercury can and does adversely affect neurological development and functioning. However, long term exposure at substantially higher doses than present in thimerosal are necessary for such impact. The mercury in thimerosal is ethyl-mercury, which is not fat-soluble. Unlike the fat-soluble form of methyl-mercury (industrial mercury), ethyl-mercury is flushed from the body very quickly. Methyl-mercury can be readily absorbed into fatty brain tissue and render its damage through protracted contact. Methyl-mercury works its way into the food chain and poses a hazard to us if we eat too much fish (particularly those at the high end of the food chain). In reality, one is at more risk from eating too much seafood (shark and tuna) than from getting an injection of a vaccine preserved with thimerosal. Yet there does not seem to be a movement to implicate seafood as the cause of Autism.


Even though the relationship between vaccines and Autism has been thoroughly debunked, there is a movement afoot, steeped in conspiratorial thinking, that alleges that “Big Pharmacy” and the “Government” are colluding to deceive the people and that elaborately fabricated data is used to cover up a relationship. This belief lives on. How can this be so? Even intelligent and well educated people I know are avoiding important childhood immunizations based on the fear and misinformation spread by these well intentioned people.


In 2003, in the UK, the MMR vaccine rate had fallen to below 79% whereas a 95% rate is necessary to maintain herd immunity. Currently, the vaccine rates are dropping in the US due to the efforts of celebrities like Jenny McCarthy who purports that her son’s Autism was caused by vaccines. McCarthy campaigns fiercely against childhood immunizations spurred on by the likes of Oprah Winfrey. Even folks like John McCain, Joe Lieberman, and Robert F. Kennedy, Jr have spread such misinformation. Continuing to contend that the MMR vaccine is the culprit, Wakefield has moved to the US and has risen to martyr status among the anti-vaccine folk. You need to know that just months before he published his seminal paper, Wakefield received a patent on a Measles Vaccine that he alleges, “cures” Autism. He has much to gain financially, in his attempt to scare people away from the current safe and effective MMR vaccine.


It amazes me that people do not automatically dismiss this alleged vaccine-Autism link. Wakefield’s conflict of interest and discredited research practices alone draw into question anything he has to say. The mountains of epidemiological evidence also favors rejection of a causal relationship between the MMR vaccine and Autism. However, the power of anecdotes and misguided beliefs place millions of children in harm’s way.


Imagine yourself as a parent of a child who cannot get the MMR vaccine because of a serious medical condition (e.g., cancer). Such vulnerable children, of which there are millions worldwide, depend on herd immunity for their very survival. Now imagine that your child is inadvertently exposed to measles by coming into contact with a child who wasn’t vaccinated (because of misguided parental fear). Because your child’s compromised immunity, she develops the measles and gets seriously ill or dies. Such a scenario, although improbable is not impossible. It is more likely today largely due to the diminished herd immunity caused by misinformation. Whooping Cough (Pertussis) is likewise posing serious concerns (and one documented death) in unvaccinated clusters because of the anti-vaccine folk. This myth persists, in part, because of the Illusion of Cause, and the consequences have become deadly. Next week I will delve into this Illusion that sustains this erroneous and dangerous belief system.




Association for Science in Autism Treatment. (2009).  Autism & Vaccines: The Evidence to Date. Vol. 6., No. 1


Center for Disease Control. Autism Spectrum Disorders: Data & Statistics.


Chabris, C. F., & Simons, D. J. (2010).  The Invisible Gorilla. Random House: New York.


Plait, P. (2010). The Australian antivax movement takes its toll. Bad Astronomy Blog.