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Brain Evolved Preference for Anecdotal Evidence

Skeptic Ginger

Nasty Woman
Joined
Feb 14, 2005
Messages
96,955
Some of you know I have been an advocate for addressing the underlying causes of people's false beliefs and not to only address the false information they believe. Here is a brief comment from Shermer published in SciAm that adds to our knowledge base on the function of the brain that contributes to why people believe anecdotal evidence more readily than scientific evidence.

How Anecdotal Evidence Can Undermine Scientific Results

I assume this is a no brainer for many of you. But I was wondering what solutions people thought might address this problem.

I have brought the problem to people's attention when trying to persuade them to think more critically. I have given them examples of the fallacy involved. But that isn't enough to convince many people that their personal experience upon which they drew a conclusion was not a reason to draw said conclusion.

There must be a more effective way to address this barrier to learning than just pointing it out to people.
 
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"My flu was cured by taking Homeopathy Pill X" Vs. An analytic metaanalysis of homeopathic remedies Vs. placebo in the treatment of influenza

"Peter Poppoff saved Mrs. X from cancer." Vs. "Peter Poppoff is a fraud. More news at 11."

"You know that Sylvia Brown? She saved little Timmy from being kidnapped." Vs. "Eeew...that James Randi is an atheist. Atheist are liars."
 
What you need is an anecdote...

You know, that actually is a valid point. I do use anecdote examples to illustrate the fallacy when I point it out to people using an anecdote to justify an unsupportable belief. Trouble is, it is not their anecdote.
 
"My flu was cured by taking Homeopathy Pill X" Vs. An analytic metaanalysis of homeopathic remedies Vs. placebo in the treatment of influenza

"Peter Poppoff saved Mrs. X from cancer." Vs. "Peter Poppoff is a fraud. More news at 11."

"You know that Sylvia Brown? She saved little Timmy from being kidnapped." Vs. "Eeew...that James Randi is an atheist. Atheist are liars."
One example of what I was thinking of comes to mind. I had a long discussion with a friend trying to explain to her why the fact that she had some symptoms at some point after getting a flu shot did not mean the flu shot caused the symptoms.

These kind of personal experience, temporal events in particular are the hardest to counter.

With examples like your last one, the issue is more one of selective credibility assigning to our various sources of information. There is a different process involved in simply choosing which sources are credible and which aren't.
 
One example of what I was thinking of comes to mind. I had a long discussion with a friend trying to explain to her why the fact that she had some symptoms at some point after getting a flu shot did not mean the flu shot caused the symptoms.

These kind of personal experience, temporal events in particular are the hardest to counter.

With examples like your last one, the issue is more one of selective credibility assigning to our various sources of information. There is a different process involved in simply choosing which sources are credible and which aren't.

Good point. People tend to trust their own senses but our senses and brains are easily fooled especially when it comes to correlation/causation fallacies.

The best we can do is to teach others that our senses are fallible and our brains are easily fooled...that may awaken them to learning and using the scientific method in their lives.

PS: Well the flu shot can cause muscle aches and pains and can cause a brief fever...a mini-flu.
 
It's not a no brainer for me. Actually I find it hard to agree with much of it.

Well a personal experience is by definition NOT anecdotal: anecdotes are not necessarily anecdotal.

Nor actually is Shermer's first example; that is a false correlation. Correlation does not require causality, so the vaccine is unrelated to the onset of autism, though they do correlate - and as correlation often does mean causality, it is a failure to understand that it that the correlation is false that causes the problem. However, it is nothing to do witrh anecdotes, or anecdotal evidence! It's actually misapplied logic and bad science. :)

Again Wigmore seems to have engaged in false correlation, based on empirical evidence but utterly misleading. She presented her evidence, but it was nonsense - she was wrong. (Whether she could have told that at that period in history I know not, given the complexity of the biochemistry involved.) However her methodology seems to have been observation and then a false inference, with strange religious ideas supporting this mistaken chain of reasoning. It is not as I understand it however anecdotal?

And finally, anecdotal reasoning in no way undermines science: just the public acceptance of science? It just undermines faith in scientific and presumably efficacious cures, among those who would prefer to pursue chimerical junk? Science continues quite happily?

I like the evolutionary logic that false positives having less danger than false negatives are usually ignored though, and as always I have a great deal of respect for the excellent Michael Shermer, but I can't make much sense of why the original article was retitled as it was.

cj x
 
It may be confounded by the apparent fact that conscious processing takes place after the facts. So people quickly make up their mind about what happened - after the fact - and then are certain that is what happened at the time it happened, not recognizing that it is really what they consciously decided after the fact.

ETA in an odd twist, it seems to me that scientific thinking is trying to circumvent a part of the mechanism of natural selection. That anecdotal rapid decision and action, without knowledge is probably part of what evolved us to the point where we could start thinking about things more analytically. Now we are trying to over ride that in favor of this thoughtful analysis. Its kind of like dieting, for the mind.
 
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Actually I'd better check this - maybe it's a UK/USA thing?

My UK understanding of anecdotal evidence is "hearsay, evidence given that is not direct witness testimony; or the result of scientific research undertaken to demonstrate a claim"

Does it mean something different in the US?

cj x
 
Actually I'd better check this - maybe it's a UK/USA thing?

My UK understanding of anecdotal evidence is "hearsay, evidence given that is not direct witness testimony; or the result of scientific research undertaken to demonstrate a claim"

Does it mean something different in the US?

cj x

an·ec·dote Audio Help /ˈænɪkˌdoʊt/ Pronunciation Key - Show Spelled Pronunciation[an-ik-doht] Pronunciation Key - Show IPA Pronunciation
–noun
a short account of a particular incident or event of an interesting or amusing nature, often biographical.
http://dictionary.reference.com/search?q=anecdote&x=0&y=0

It often meant here as a personal story or experience.
 
an·ec·dote Audio Help /ˈænɪkˌdoʊt/ Pronunciation Key - Show Spelled Pronunciation[an-ik-doht] Pronunciation Key - Show IPA Pronunciation
–noun
a short account of a particular incident or event of an interesting or amusing nature, often biographical.
http://dictionary.reference.com/search?q=anecdote&x=0&y=0

It often meant here as a personal story or experience.

Yeah, that is an anecdote here too, usually a personal experience related, though not necessarily. Hence my assertion anecdote is not necessarily equal to anecdotal evidence, as a personal anecdote related by a victim of a crime would be admissible in court, being a short statement of their own direct experience - whereas anecdotal evidence, as in "I heard on the bus that Bob saw the UFO" is not?

Well anecdote means the same in the uK and USA anyway! Thats good to know. Cheers!

cj x
 
Re: the OP:

One time I was talking to someone, and I presented really good, solid evidence for what I was saying, but he didn't believe me. When I asked why, he told me a story about his grandmother.
So I think you're right.
:P
 
Good point. People tend to trust their own senses but our senses and brains are easily fooled especially when it comes to correlation/causation fallacies.

The best we can do is to teach others that our senses are fallible and our brains are easily fooled...that may awaken them to learning and using the scientific method in their lives.

PS: Well the flu shot can cause muscle aches and pains and can cause a brief fever...a mini-flu.
Paxi, I hope that last line was sarcasm.

With the exception of very young children, research indicates it is a myth.
 
It is not enough to point out the fallacy of anecdotal evidence, because other weaknesses of the human mind evolution take effect, such as cognitive dissonance, and sunk cost strategies, etc.
So if it is not enough, is our only hope then to wait for the old to die out and hope to reach the young at an earlier age teaching them how to overcome the brain's shortcoming? :p
 
I have brought the problem to people's attention when trying to persuade them to think more critically. I have given them examples of the fallacy involved. But that isn't enough to convince many people that their personal experience upon which they drew a conclusion was not a reason to draw said conclusion.


That is an example of anecdotal evidence. "I brought the problem, I gave them examples, It wasn't enough". Somebody tells a short account of their personal experience, and concludes that they did something to try and change another persons mind, but it didn't work. Or rather, it wasn't enough, I need to do more.

Whatever. We don't always recognize when we do the same thing we find flawed in others.

Like starting off a thread about anecdotal evidence with anecdotal evidence. I would suspect deliberate irony, to bring about a humorous response, but that might be giving too much credit.

It does show how deeply ingrained humans are when it comes to observing what happens, and foolishly believing what they observe counts as evidence. They must be trained, taught, to doubt their own experience, and only trust experts who do experiments and use science to determine reality.

Especially parents. They see their kid fall out of a tree, and they assume the injuries that appear right after the event, were caused by the fall. They don't realize that until proper experiments and evidence are provided, they can't know that it was the fall.

Kids at that age often have broken arms, head trauma, and bleed profusely, just because one thing happened, then the injuries appear, doesn't mean they are connected.

Of course parents might come around and stop being so dumb, if we could only show them the evidence. Sadly, they probably would still insist the fall led to the injuries. Same for hot objects, sharp pointy things and electric sockets.

Stupid parents. They trust their own experience over an expert who was paid a lot of money to show that nothing we inject into a child ever causes any harm, it is always just coincidence that kids get sick and develop serious symptoms right after multiple injections.

I don't think anything can really be done about it. Except maybe jailing anyone who questions authority, and refuses to allow their kids to be injected.

Oh sure you have those Amish with there lack of autism. But it is just coincidence that they refuse all vaccines. Or it could be genetics. How do we know? Well, we don't,but somebody said it was genetics so that is good enough.

Same for that other group of religious nutjobs who refused all vaccines. Sure they have almost no autism, but again, it is just coincidence. Same for those isolated tribes that never get vaccinated.

It is either coincidence or genetics. It can't be anything anyone did, despite how it seems. Parents just need to shut up and quit rocking the boat.

Kids just naturally go from normal to autistic, at the exact same time they get a buttload of vaccines. Stupid experience, always getting in the way of theories and evidence.

Oh, and all those stupid Doctors and researchers that find a connection between vaccines and health problems, they are all stupid too. Like those European countries that banned mercury. They are so dumb. They think mercury might be hurting kids.

Ha! That can't be true, because everybody agrees it can't be true.

What? No no, trust me. If a scientist or a Doctor says something, it must be true. Unless it is one of those Doctors that says something we don't agree with, then they are wrong.

Oh sure we could do animal studies, inject a bunch of monkeys and chimps babies and mothers with vaccines and adjuvants to actually see if they can cause neurological problems, but since we don't have any evidence to show mercury or vaccines causes any problems, what would be the point? I mean, it said right there in the OP article that "On the one side are scientists who have been unable to find any causal link between the symptoms of autism and the vaccine preservative thimerosal". See? They looked, but can't find any evidence.

So what would be the point of doing research and actually testing the stuff out? Plus that kind of research is expensive and stuff.

Oh sure, you might think adjuvants would be required to be tested before we use them, but we have been using them since 1947 or so,
so why worry about it now? Same for mercury. It has been used for a long time, without any testing, why would you want to actually do all that hard science to find out what it can do to developing babies and pregnant moms and stuff?

I mean, if you inject a bunch of pregant chimps and then inject the little chimp babies and study what happens, you might hurt the little chimp babies. Or worse, waste time and money. Because we already know the answer, we don't need to do any experiments, studies, all that scientific crap.

Scientist found no evidence, and that closes the case. If you look real hard, and there is nothing to show any evidence, why would you want to do animal studies and all that expensive and time consuming really hard stuff? If you already know, you don't have to do anything.

Besides, they stopped using mercury, except for when they still use it (every year, but only for babies and pregnant moms), because the Flu is dangerous, so mercury is OK then. But it can't be mercury, because we stopped using it. What? Something else in the vaccine? Don't be absurd. Next you will want extensive animal studies done on all vaccines and adjuvants and everything. Do you think we are made out of money?

Besides, testing all those combination's of vaccines would be a lot of work.


But anyway, people are just so dumb, they think they know there kids intimately, and can tell when something effects them and makes them sick. They just need to realize that Pharmaceutical companies and researchers never lie, and if they tell you something, it has to be true.

So Parents, stop believing your own experience, and start trusting the Government and the Drug Companies. They are only here to help you.

And stop asking for animal studies and all that crap. We told you, we found NO EVIDENCE!! Why can't you just believe? Why are you so skeptical of our claims? Trust us, we never hurt a single child, and we are never wrong about stuff we give kids and moms.


And if you say different, you are wrong. Because we said so.​
 
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One should note that not all anecdotes are wrong, and while anecdotes can lead to superstitions which can even spawn religions and all sorts of strange beliefs, there are actually other reasons which produce and lead to religious thought as well (the desire to believe in things bigger than ones-self, to trust their parents, and even due to neurotransmitter responses to comforting thoughts)... still, I wouldn't give anecdotes too much weight all the time anyway.


INRM
 
Yeah, that is an anecdote here too, usually a personal experience related, though not necessarily. Hence my assertion anecdote is not necessarily equal to anecdotal evidence, as a personal anecdote related by a victim of a crime would be admissible in court, being a short statement of their own direct experience - whereas anecdotal evidence, as in "I heard on the bus that Bob saw the UFO" is not?

Well anecdote means the same in the uK and USA anyway! Thats good to know. Cheers!

cj x
There may be a difference in what I am talking about and what you are talking about if you consider legal definitions of evidence. I am talking about evidence one uses to draw conclusions. The admissibility of evidence in a court is a completely different matter.

Personal experience is a more precise term for what I am referring to. 'Anecdotal evidence' is the scientific term for a personal experience one uses as evidence.

One can also believe such personal anecdotes by proxy such as the grandmother's anecdote that Roboramma described in the above post. The 911 truthers that believe the anecdotes of witnesses have more significance than the testimony of structural engineers would also be considering anecdotal evidence (or in that example, eye witness testimony). On the other hand, 911 truthers who prefer a rogue structural engineer's testimony over an 'establishment' structural engineer is not an example of what I am talking about, even though in those two examples, trust one assigns to different sources is also a factor.

Some people have a very hard time believing that the conclusions one draws from either their own or someone else's personal experience is subject to all sorts of errors. Take the flu shot example. Lots of people get sick after flu shots. We give flu shots during the time of the year when commonly acquired infections are the most frequent. Kids return to school. The few children passing things to an occasional neighbor, cousin, or sibling over the summer are suddenly in confined classrooms with dozens of kids. Then those kids go home and infect their parents who by October are passing the infection on all over the community.

The conclusion the flu shot was the cause of the illness is common but mistaken conclusion. How do we know? Using the scientific method rather than basing assumptions on uncontrolled experiences, we take a large enough group of people, blindly randomize them into two groups (or 3 if you want a no-treatment arm of the study) and give half a flu shot and the other half a shot of saline. Then you collect the data on who got sick and then compare the group who got the vaccine with the group(s) that didn't.

Lo and behold the rate of illness is the same in both groups as was found in the study I cited in a previous post.

Scientific method leads you to a valid conclusion. Anecdotal or personal experience in this case leads you to a false conclusion. Your personal experience was unable to control for other variables affecting the outcome while the scientific method was. But some people are unable to recognize that fact even when presented with clear incontrovertible evidence. That personal experience was so convincing they cannot overcome its influence.
 
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That is an example of anecdotal evidence. "I brought the problem, I gave them examples, It wasn't enough". Somebody tells a short account of their personal experience, and concludes that they did something to try and change another persons mind, but it didn't work. Or rather, it wasn't enough, I need to do more.
No, it is not an example of anecdotal evidence. Simply conveying information is not what is meant by the term, anecdotal evidence.



....
It does show how deeply ingrained humans are when it comes to observing what happens, and foolishly believing what they observe counts as evidence. They must be trained, taught, to doubt their own experience, and only trust experts who do experiments and use science to determine reality.
This certainly illustrates how trust in sources of information can be affecting attempts to teach people the principles of critical thinking.



Especially parents. They see their kid fall out of a tree, and they assume the injuries that appear right after the event, were caused by the fall. They don't realize that until proper experiments and evidence are provided, they can't know that it was the fall.

Kids at that age often have broken arms, head trauma, and bleed profusely, just because one thing happened, then the injuries appear, doesn't mean they are connected....
I have pondered the fact we can trust that swinging a hammer into a glass window and watching it break is enough to draw a reliable conclusion while getting sick after a flu shot is not. Just because some personal experiences are valid evidence for conclusions doesn't mean all personal experiences are.

After all, some of our conclusions likely had to be correct in order to provide a selection pressure for a brain function that looked for causal relationships. As Shermer hypothesized in the OP piece, there was a benefit when the conclusion about the causal effect was correct (that bear is going to eat me if I don't get out of here) and not as much of a negative effect when the conclusion about the cause was not correct (if I perform this prayer ritual the harvest will be better).

In the case of immediate trauma after a high force impact, we know from experience those events are causal. In the case of the flu shot causing illness symptoms, the assumption of causality is made without consideration of the other potential variables and with only false beliefs there is experience supporting the assumptions.



I don't think anything can really be done about it. Except maybe jailing anyone who questions authority, and refuses to allow their kids to be injected.

....
Off topic ranting serves no purpose here.



What? No no, trust me. If a scientist or a Doctor says something, it must be true. Unless it is one of those Doctors that says something we don't agree with, then they are wrong.
That is also not consistent with critical thinking. It is a straw man no one is advocating.



Oh sure we could do animal studies, inject a bunch of monkeys and chimps babies and mothers with vaccines and adjuvants to actually see if they can cause neurological problems, ....
More off topic useless ranting. Take it elsewhere.

Goodness, this post is full of a number of examples of both the trust issue and it's affect on critical thinking and the trust of anecdotal evidence over scientific evidence. It contains classic examples of both.

As I said, 'giving one an example', referred to presenting scientific evidence whether it be by simply explaining what evidence exists as I did above, or providing examples of research such as in the citation I referred to. An anecdote is not simply conveying information as you seem to be defining it as.

The trust issue is not something I want to spread this thread into covering. It is important enough that it deserves another thread. But one thing at a time please.
 
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There must be a more effective way to address this barrier to learning than just pointing it out to people.

What you need is an anecdote...

Exactly. I suppose this isn't exactly practical in every debate situation, but what about creating an anecdote for the person, that they can experience first hand, and then demonstrating later that what they saw was incorrect, or led them to a false conclusion?

Magic tricks come to mind, but I suppose some people might be turned off by that. "Oh, magicians get paid to fool people. How does that relate?" Plus there is the problem that not everyone is proficient.

I can't find the article, but recently I was reading something about false memories (I think) that was an experiment involving children to show how easy it is to get kids to believe false things. With a little simple storytelling, a moderator got most of room full of kids to believe that there was a magic animal hiding in a box that he had earlier demonstrated was empty.

Maybe we could brainstorm some scenarios in this thread.
 

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