Thursday, February 28, 2013

The Unreliability of Testimony

Believe nothing of what you hear
and only half of what you see.
-Edgar Allen Poe

     Should we believe what we hear? Why is it so easy for us to believe what people have to say? We like gossip, we like hearing stories, it makes us feel good. The problem is that the human mind is so easily fooled. Now, I don't claim to be above being fooled, I will admit that I have been fooled many times, and fallen prey to the shortcuts of our mind. I believe this is one of the most important aspects to learn in being able to make good decisions based on reliable evidence. Because of the many different ways our mind can be fooled, we should never take eyewitness testimony, or anecdotal evidence as truth, or reality. I'm not saying that everyone is a liar, but that we are easily fooled into believing something that is false.

     Think back to elementary school. I'm sure many of us remember playing the telephone game, where the teacher would whisper a phrase into the fist persons ear, and then it had to be passed on down the line. If you never played this game, I encourage you to look it up and try it. As I'm sure was the case, the last person to have this phrase passed to them would then say it out loud, and I'm sure it was never the same as the original. This is a great example of how information gets corrupted being passed on orally, or through eyewitness testimony.

     There are many ways we can be fooled into thinking something false. Our being prone to believe in anecdotal information is one of them. If anyone has facebook, this is a great example, if you're anything like me, I see weekly someone sharing some information that is false, but they believe to be true. There is a few websites dedicated to debunking a lot of these Internet “urban myths”. So lets talk about all the different ways our brains can be fooled, and why we shouldn't believe what we hear.

     Lets start with confirmation bias. This happens when we want to believe one way, we tend to find information that confirms our beliefs, and discredit information that disagrees with our beliefs. This is a well documented phenomenon. We are all prone to confirmation bias, even myself. This is something we should all work to be aware of. So if you're talking to someone who believes a certain way, chances are they have looked and trusted all the information that agrees with the way they think, and won't tell you any contradictory information.

     Lets talk about some logical fallacies. These are ways our brains get tricked into thinking something sounds logical, when really it isn't. I've posted a list of these in an earlier post, but I will cover some more here.

     Argument from ignorance. This is when one goes from a statement of uncertainty to a statement of certainty. For example, I don't know what those lights are in the sky, they must be aliens from another planet. Or I don't know what that noise was in the house, therefore it must be a ghost. You can see where the logic is failing in this. You cannot go from an abject statement of uncertainty, to an abject statement of certainty.

     Argument from authority. Just because someone claims they are an expert, or has initials after their name, doesn't always make them right. One of the times we see this is when a PhD in one field, makes statements or assertions about a field they know little about. Just because someone has a PhD in physics, it doesn't make them an expert in biology.

     Argument from popular belief. Just because a lot of people believe it's true, it must be true. It doesn't matter how many people believe in something, it doesn't make it true. Also it doesn't matter how few people believe in something, it doesn't make it false. The Earth will continue to travel around the Sun, regardless of how many people believe it's true or not.

     These are common arguments that can lead to false beliefs. They can trick people into believing something that might not be true. We have had an entire culture of UFOs spring up because of people making an argument from ignorance. Now with the advent of everyone having a cell phone with a camera and the Internet, these sightings are being recorded and quickly identified.

     I'm going to go quickly into the placebo effect, as I covered it in my last post. People can think something makes them better, when the reality is that it did nothing. The placebo effect can work both ways though. If someone thinks something is bad for them, they will get sick from it. This is referred to as the “nocebo” effect. The nocebo effect is one of the common arguments against electromagnetic radiation, and people getting sick from it.

Cum hoc ergo propter hoc. I've discussed this before as well. It states that a correlation between two variables implies causation. There are a lot of people, always falling for this in many situations. We have evolved great pattern recognition ability. However this great ability sometimes sees patterns and connections that aren't there.

This brings us to patterning. Because we are so good at seeing patterns, we tend to see patterns in true randomness. Many conspiracy theories come from us noticing patterns in random events. Or connecting things that have no relation. Most people have trouble recognizing a random pattern as random. The reason for this is that randomness naturally has clumping. We tend to see this clumping as a pattern.

In conclusion, there are lots of ways we can be fooled into believing something false. This doesn't make us dumb, or liars. This technique of using anecdotal evidence to get you to believe something is used extensively by the people peddling pseudoscience and pyramid scams. Beware, if someone is trying to convince you of something and all they're presenting you is success stories, chances are they are scamming you. I know we've all seen this sales pitch before, don't fall for it, demand real evidence for the efficacy of a product or system. Before we believe what someone tells us, we should look at the evidence backing this up. Now, we can get into a philosophical discussion of what needs evidence, and when we should trust someone at their word, but we won't.

extraordinary claims require extraordinary evidence – Carl Sagan

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