Wednesday, September 26, 2012

Why texting while driving is a bad idea

Today I want to turn again to the issue of perception. Before I discuss the topic for today, I want you to watch this video. Then, below the fold I will discuss some of the interesting implications that this video has for our understanding of human perception.

Tuesday, September 25, 2012

Reality has a well-known liberal bias

Wishful Thinking is a fallacy in which on argues that something is true because she wants it to be true. As should be clear, this is a fallacy because the universe is generally indifferent to what we want. Reality is objective and wishing things worked differently is not going to make them happen. In my daily reading of the news I cam across this story on about a website, UnSkewed Polls which claims to correct for liberal bias in all national polls. According to the author of this site, all national polls are skewed towards the democrats due to liberal bias among the pollsters. The author then claims to be able to correct for this bias, and when he does so, it appears that Romney is leading Obama by 7-10 points, a significant margin.

The basic "methodology" if we can call it that, is to assume that the votes of Republicans are under-counted, so the author simply reweights the polls so that, in his opinion, Republicans are no longer under-counted. For example, the author assumes that 34% of voters are Republicans. So, if a poll shows that only 24% of the respondents are Republicans, then the data must be skewed. So, the author reweights the data as if those 24% of respondents actually accounted for 34% of respondents. Basically he just gives more weight to the polling data of people identified as Republicans. Unsurprisingly, this reweighting seems to always lead to Republican dominance in the polling. Basically he is counting each Republican vote multiple times, which naturally leads to Republican dominance in the polling. If you don't believe that this is what the author is doing, you can read the details of this "methodology" here.

As should be obvious, this is a classic example of wishful thinking. The author doesn't like how reality is structured, so he just wishes up a new reality and assumes that to be correct. The problem, of course, is that the people who conduct the polling are really quite good at it, and very good at correcting for various biases. As Nate Silver of the NY Times notes:
First, the polling by this time in the cycle has been reasonably good, especially when it comes to calling the winners and losers in the race. Of the 19 candidates who led in the polls at this stage since 1936, 18 won the popular vote (Thomas E. Dewey in 1948 is the exception), and 17 won the Electoral College (Al Gore lost it in 2000, along with Mr. Dewey).
If the author of UnSkewed Polls was correct that polls have a statistically significant liberal bias, then why are they accurate predictors of the winner of the popular vote 94% of the time? If such liberal bias was infecting the polls, we wouldn't see them as accurate predictors of the winner so often. Thus, the only way the author of Unskewed Polls can object to polling data is by making up his own methodology that tells him what he wants to hear. As Stephen Colbert famously remarked concerning George W. Bush's falling approval ratings:
Now, I know there are some polls out there saying this man has a 32 percent approval rating. But guys like us, we don't pay attention to the polls. We know that polls are just a collection of statistics that reflect what people are thinking in reality. And reality has a well-known liberal bias ...

Monday, September 24, 2012

Big Pharma Hides the Truth

The science columnist, author, and academic Dr. Ben Goldacre, has just written a new book about the pharmaceutical industry, Bad Pharma: How Drug Companies Mislead Doctors and Harm Patients. In connection with the publication of this book, The Guardian has published an excerpt. In this excerpt, Goldacre discusses a number of fallacies regularly committed by the pharmaceutical companies in their efforts to get their drugs approved for use by various government regulatory agencies. We can see these fallacies clearly exemplified in Dr. Goldacre's discussion of the anti-depressant reboxetine.

Friday, September 21, 2012

Two Dimensional Eyes, Three Dimensional World

Having taken a break from perception to discuss some of the latest political idiocy, I want to conclude my posting this week with a little more discussion of perception. My comments here are taken from the excellent, interactive website on the brain published by McGill University. They have an excellent section on perception which discusses vision from the molecular level all the way to the social.

One facet of the site that really caught my attention was the discussion one of the major sources of visual ambiguity, which is the fact that our visual system, specifically our retina, is only capable of taking in information about a two-dimensional world, yet our brain is able to create the visual impression of living in a three-dimensional world. Let me quote the explanation from the website:
One important source of ambiguity for the visual system is that the world is three-dimensional, but the images that it projects onto your retina are two-dimensional. Hence differing objects, depending on their distance and orientation, may occupy the same amount of surface area on your retina. Your brain therefore becomes confused, and tries to use other indicators to clarify the situation. Two such indicators are your own past experience with the object in question and the experience of the human species, which is encoded in your genes.
 They even include a helpful picture which shows how three different objects could produce the same image on our retinas:

This ties in nicely with the waterfall illusion I discussed earlier. The key there was that the impression of an impossible object was created through perspective. The artist was able to create what appeared to be an impossible object in the real world by exploiting the fact that our retinas can only receive information two-dimensionally. Thus, when we observe these different objects from the correct perspective, they appear to be one unified, impossible object.

A further illustration can be found on this interactive webpage.

Thursday, September 20, 2012

They're coming to cut your throat! And they have Korans!

On the September 18th edition of the Fox News show Your World with Neil Cavuto filmmaker Michael Lynch was interviewed about his new movie about illegal immigration. In the course of this interview Lynch commits a number of fallacies:

The most obvious fallacy is the use of Scare Tactics. Note that the video start with a news report about a prison break on the Mexican side of the US-Mexico border. Cavuto and Lynch then imply that all 130 of these prisoners are extremely violent and that they are making a beeline for the US. Note as well that we are told nothing about the prisoners. For all we know they may all have committed the Mexican equivalent of white collar crimes and are non-violent offenders. Even assuming that they are violent offenders, there is no evidence that every single one of them (or any of them) will head to the US. For all we know these escaped prisoners may make an effort to reunite with their families in Mexico. Furthermore, it is even possible that some of the prisoners are US citizens. We have no idea, the report gives us no information, but tries to scare us and make us afraid of all the murderous violent immigrants who are heading are way.

Lynch then almost immediately invokes 9-11, attempting to draw a link between illegal immigrants snaking across the US-Mexico border and terrorism. At this point it is worth noting that none of the 9-11 hijackers entered the US this way. All of them exploited legal means of entry. This is clearly an example of a False Analogy, as it is wildly inappropriate to invoke 9-11 when discussing the status of the US-Mexico border. Lynch doubles-down on this false analogy when he claims that someone is finding Korans and prayer rugs in the middle of the desert. I have no idea if this claim is true, but I find it highly suspicious. If in fact Muslim terrorists were sneaking across the US-Mexico border, I doubt that they would be scattering their holy book across the middle of nowhere.

From this Lynch then employs another Scare Tactic, claiming that not everyone is coming to the US to cut your lawn, some of them are coming to cut your throat. Again, no evidence or statistics are provided for this claim, Lynch just asserts it with the obvious intention of scaring the Fox News viewers into buying his movie.

We then see a nice example of Inconsistency when Cavuto asks Lynch why immigrants are coming to the US and Lynch responds, "Jobs," thereby directly contradicting his earlier assertion that at least some of the immigrants were coming to commit murder.

Lynch then transitions to an Appeal to Authority citing a positive review from some Fox News celebrity as evidence that his movie is worthwhile and important.

Finally he concludes with the classic huckster's pitch claiming that he has secret information that "They" (whoever "they" are) don't want you to see. In this connection Lynch implies that there is some large-scale conspiracy devoted to suppressing the truths that he, as a normal, hard-working American, is trying to expose. In general, when someone cites a conspiracy as the reason why no one will show their movie, we need to seriously consider the possibility that no one will distribute or screen the film because it sucks, not because it reveals some uncomfortable truth.

h/t to Media Matters

Wednesday, September 19, 2012

Don't go chasing waterfalls. You just run around in circles.

Most people are familiar with this very famous optical illusion designed by M.C. Escher:

This illusion works because Escher is exploiting the way our brains perceive perspective in order to create a visual paradox. Most artists use these rules of perspective to create realistic three dimensional images on a two-dimensional piece of paper, but Escher is manipulating these rules to create this famous illusion.

Despite the fact that this illusion has its origins in the exploitation of rules of perspective in drawing, it turns out that one can actually build such an object in the real world! A video is below the jump.

Tuesday, September 18, 2012

In the eye of the beholder

One of the coolest things about optical illusions is what they reveal about how human perception works. One of my favorite optical illusions in this respect is the Checkershadow illusion discovered and analyzed by Edward H. Adelson in 1995. Here is the illusion:

The trick here is to look at squares A and B. B obviously appears to be a much lighter shade of gray than A. However, if we isolate the two squares from the larger context, we can actually see that they are the same shade of gray. This gif below the jump illustrates that point:

Monday, September 17, 2012


Last week I talked a great deal about audio pareidolia and audio illusions generally. This week I want to spend some time on the visual. As a reminder, Pareidolia is a phenomenon in which vague or random stimuli are perceived as significant or meaningful.

For some reason I have been running across many examples of visual pareidolia, so I thought I would share them on the blog. This first image is a nice example of pareidolia on a tree:

I assume everyone can see the owl face in the tree.
This next example of pareidolia comes from an overhead image of some flamingos, ironically in the shape of a flamingo:

This last image is one of the most common types of pareidolia, an image in the clouds:

So, there are three nice examples of visual pareidolia. I will post more visual illusions in the upcoming days.

Wednesday, September 12, 2012

The McGurk Effect

On the webpage were I found the example of audio pareidolia I discussed last time, there was also a video talking about something I had never heard of before, the McGurk effect. The video does an excellent job explaining the effect and what is going on with it:

There are a few interesting points from this video that I wanted to highlight. First, this effect really demonstrates the role our brains play in constructing our experience of the external world. The brain takes in stimuli from the various senses, and then seeks to integrate those stimuli into a cohesive whole which is what we then experience. We do not directly access the world through our senses, rather our brains construct the reality we experience. A second interesting feature of the McGurk effect is that it demonstrates the primacy of visual stimuli over auditory stimuli. When there is a conflict between the two (as when we hear the word "ba" but see the speaker moving his lips as if he were saying "fa") our brain privileges the visual and corrects what we hear to match what we are seeing. This is closely related to the audio pareidolia I discussed in my previous post where the captioning really assists one in hearing what is being sung. A third interesting feature of the McGurk effect is that this is a perceptual illusion that we can't avoid hearing. Even if we know that the word being said is "ba," when our eyes see the lip movement for "fa" we can't help by hearing "fa." This demonstrates that even when our perceptual faculties are functioning perfectly, we can still succumb to systematic unavoidable errors.

The take away from this (as with all perceptual illusions) is that we should recognize the unreliability of our experience and the experience of others. This is why when someone relates some incredible, unbelievable experience that they had, we should be skeptical about the veracity of that experience. This is also why anecdotes and eyewitness accounts are so unreliable.

Tuesday, September 11, 2012

Green Chalk Can Taste Like Hippies

In a previous post I discussed the phenomena of pareidolia, which is when our brain interprets random stimuli as being meaningful or significant. This phenomena is most common with visual perception, but it also occurs with auditory perception. Here is a funny example:

The song in question is "O Fortuna" and you have probably heard it before in movies and other media. It is based on a Latin poem written in the 13th Century and then set to music by Carl Orff in the 1930's. What I find interesting about this example of pareidolia is the role that the captioning plays. I have heard this song numerous times, but I never really paid attention to the lyrics until I came across this video. With the captions in front of me it then becomes very hard to not hear silly things in the song. And this suggests how our brains construct reality for us, taking in information from all the senses and then processing it to create a unified, meaningful experience of the world around us. I will talk more about this in subsequent posts.

Here are some other good examples of audio pareidolia. If anyone has any other examples, or perhaps song lyrics that you have always misheard, I would love to hear about them in the comments.

Monday, September 10, 2012

Sen. Paul, perhaps you should educate yourself before you get angry.

We live in a very interesting time in American politics. We live in a time when people who are the most outraged about an issue are also the people who know the least about it. As a case in point, watch this exchange between Sen. Rand Paul and Paul Krugman about the number of public employees in the US under Bush and Obama:

Sen. Paul is very concerned about the size of the government, but as Krugman notes in the video and at his blog, the size of the government has shrunk dramatically under Pres. Obama. In fact, as Krugman argues, this is one of the major reasons the recession has dragged on for so long. Now in fairness to Sen. Paul, employment at the federal level has increased slightly from about 2.77 million in 2008 to about 2.8 million now, but that certainly isn't an "enormous" growth of government as Sen. Paul suggests. Furthermore, given that state and local governments have been slashing jobs at an enormous rate, the total number of government employees (Federal, State and Local combined) is down about 600,000.

Yet, despite these facts, Sen. Paul seems outraged at the size of the government. What are we to do when people become outraged about topics they appear to know nothing about? Our post-truth election continues.

Friday, September 7, 2012

Red Herrings in AP "Fact-Checking"

Fact-Checking is apparently a big thing these days (particularly in the wake of Paul Ryan's falsehood-filled speech at the Republican National Convention), with everyone trying to get in on the game. However, not all fact-checkers are created equal. In the AP "Fact-Checking" of Bill Clinton's speech at the Democratic National Convention by Matt Apuzzo, there is a great example of a Red Herring:
CLINTON: "Their campaign pollster said, 'We're not going to let our campaign be dictated by fact checkers.' Now that is true. I couldn't have said it better myself — I just hope you remember that every time you see the ad."
THE FACTS: Clinton, who famously finger-wagged a denial on national television about his sexual relationship with intern Monica Lewinsky and was subsequently impeached in the House on a perjury charge, has had his own uncomfortable moments over telling the truth. "I did not have sexual relations with that woman, Miss Lewinsky," Clinton told television viewers. Later, after he was forced to testify to a grand jury, Clinton said his statements were "legally accurate" but also allowed that he "misled people, including even my wife."
As you can see, this comment on the speech really doesn't address the claim that Bill Clinton made, but rather tries to change the subject by introducing an irrelevant consideration, namely Bill Clinton's conduct during the Monica Lewinsky scandal. While it is true that Clinton has been deceptive and slippery in the past, that is completely irrelevant to the question of whether or not the Romney campaign is being honest. The fact is, Romney's campaign manager did say the quote attributed to him, and for the AP to ignore that and instead start talking about the Lewinsky affair is a perfect example of a Red Herring.

h/t Alex Pareene

Wednesday, September 5, 2012

Same-Sex Marriage Lies and Distortions

On the Minnesota ballot in November is a constitutional amendment to ban same-sex marriage by defining marriage as between one man and one woman. As is always the case when these issues come up a great deal of money is spent by people on both sides of the campaign. One group in favor of the proposed amendment is Minnesota for Marriage which has produced a series of web videos arguing in favor of the proposed amendment. In their latest video they have invoked a recent study that they claim shows that couples raised by homosexual parents do far worse on a variety of measures than children raised by heterosexual parents. Watch the video, and then I will discuss a fallacy committed by it.

The primary fallacy committed in this video is the Suppression of Relevant Data. In particular, the actual results of the study are seriously misrepresented in the video. In particular, what the video fails to mention is that the study does not actually compare children raised by heterosexual parents with children raised by homosexual parents. Instead, it is a study of children raised in families where one of the parents engaged in a same-sex affair, often resulting in the destruction of the that family unit. In particular, the study only looks at children born between 1971 and 1994, a period when gay marriage was illegal. The study then looks at marriages in which at least one of the partners had homosexual tendencies that they suppressed in order to lead a "normal" life. As is no surprise, for many of these people the burdens of a sham marriage and the pressures to hide their true desires led them to act out in various ways that were destructive of that marriage; a destruction that naturally had negative impacts on the children born of that union. In effect then, what the study shows is that children from broken households do worse than children from intact households, a conclusion that should surprise no one. The study is criticized in Slate by William Saletan who does a good job pointing out the methodological issues with the study that lead groups like Minnesota for Marriage to misrepresent the results of the study. Saletan concludes by suggesting that what the study really shows is that:
Kids do better when they have two committed parents, a biological connection, and a stable home. If that’s good advice for straights, it’s good advice for gays, too.
This seems accurate, but that is a point that Minnesota for Marriage ignores by suppressing the actual details of the study in order to draw their own ideological conclusions.

Monday, September 3, 2012

Paul Ryan's Inconsistent Address

Much ink has been spilled concerning the various lies and distortions in Paul Ryan's address at the Republican National Convention, but I want to focus on an Inconsistency he commits. As a reminder, Inconsistency occurs when one part of a persons argument contradicts another part of that argument. Let's look at the relevant passages (a transcript can be found here). First, Ryan attacks Obama for cutting $716 billion from Medicare (it is actually not a cut, but a plan to reform Medicare Advantage reduce reimbursement rates to doctors, thereby saving $716 billion). About this, Ryan said:
You see, even with all the hidden taxes to pay for the health care takeover, even with new taxes on nearly a million small businesses, the planners in Washington still didn't have enough money. They needed more. They needed hundreds of billions more. So, they just took it all away from Medicare. Seven hundred and sixteen billion dollars, funneled out of Medicare by President Obama. An obligation we have to our parents and grandparents is being sacrificed, all to pay for a new entitlement we didn't even ask for. The greatest threat to Medicare is Obamacare, and we're going to stop it.
In Congress, when they take out the heavy books and wall charts about Medicare, my thoughts go back to a house on Garfield Street in Janesville. My wonderful grandma, Janet, had Alzheimer's and moved in with Mom and me. Though she felt lost at times, we did all the little things that made her feel loved.
We had help from Medicare, and it was there, just like it's there for my Mom today. Medicare is a promise, and we will honor it. A Romney-Ryan administration will protect and strengthen Medicare, for my Mom's generation, for my generation, and for my kids and yours.
Ignoring for the moment that Ryan's own budget plan makes nearly identical cuts, and that restoring such cuts would actually speed up the point at which Medicare would become insolvent and increase premiums for seniors, he goes in in the speech to argue for the need to cut entitlements:
None of us have to settle for the best this administration offers – a dull, adventureless journey from one entitlement to the next, a government-planned life, a country where everything is free but us.
So, he will defend entitlements like Medicare by restoring a cut made to it, thereby increasing its size, but at the same time will reduce entitlements.  I think Matt Taibbi summarized this argument best as:
My fellow Americans, whatever Barack Obama is doing with Medicare, it's bad, and we promise to reverse it!
And not only that, we'll go even further in cutting wasteful entitlements from our bloated government budget!
And here we can clearly see the inconsistency in the argument. On one hand he will defend entitlements, but on the other hand he will cut them.  So, which one is it?