Science + Media = Bad News

The media seems to love scientific studies. Every week there seems to be a story on the local news about a new study telling us about how to reduce the risk of heart disease or cancer, or some other disease. Unfortunately, the news story invariably distorts the study’s results, doles out some dubious advice, and does a general disservice to their audience…

For example, recently I happened across a WebMD article entitled “Drinking coffee may extend life”. The first paragraph of the article reads:

“Coffee drinkers, rejoice. While you might be using it for a “pick-me-up,” coffee may also be extending your life.”

From this headline, your initial reaction might be:

Coffee’s good for you; it would probably benefit everyone to go out and drink coffee.

Unfortunately this assumption is pretty far from the truth. For example, further down in the article you get a quote from one of the study’s authors:

“We can’t say from this one study that coffee extends your life, but it does appear that it doesn’t increase the risk for death for people who are healthy,”

Wow, coffee doesn’t increase the risk of death for people who are healthy! That’s encouraging…

If you look up the actual study in the Annals of Internal Medicine – “The Relationship of Coffee Consumption with Mortality”, their official conclusion is:

“Regular coffee consumption was not associated with an increased mortality rate in either men or women. The possibility of a modest benefit of coffee consumption on all-cause and CVD mortality needs to be further investigated.”

Hmm… We seem to be getting further and further away from our initial assumption; maybe the devil really is in the details. Looking at the details of the study, I think an appropriate summary of their findings would be:

For those with no history of heart disease or cancer, over 20 years, your risk of dying of heart disease may drop by up to 20% in men and 25% in women, if you drink coffee.

The study doesn’t tell us anything about:

• Benefits to those that already have heart disease or cancer
• Benefits to those who aren’t at risk of heart disease
• Whether coffee increases the risk of dying of something else
• Whether coffee may negatively affect your health in other ways

So, now that we’ve correctly interpreted the study’s results, do we actually believe them? I don’t…

Why does coffee reduce the risk of heart disease? We can guess, but in reality, we have no idea whether coffee actually lowers the risk of heart disease or not, or whether these numbers are due to something else. The authors of this study don’t either. They weren’t working in a lab looking at samples through microscopes, they were crunching numbers in a computer. As I’ll discuss further next week, this is not an effective way to study diseases.

Bottom line, take your coffee (and the results of studies such as these), with a grain of salt…

[Image: www.stockvault.net]

[Content © 2008 SorryToConfuseYou.com, All Rights Reserved.]

What Does Life Expectancy Represent?

Every year, the new life expectancy figures come out to grand fanfare. “Life expectancy is now XXX, up YYY years from last year”, but what does this number actually represent? Is it meaningful? You might think you know, but you’re probably wrong. I know I was…

I became curious about life expectancy statistics because my grandfather died a few years ago at the age of 94. It got me thinking, how long were people expected to live when he was born? Given all the scientific advances we’ve made in the last hundred years, how long did people of his generation actually live? Did he outlive his expected life span?

Life Expectancy vs. Expected Lifetime

Life expectancy for 2005 in the U.S. was 77.8. So, the assumption is that, on average, anyone born in 2005 can expect, on average, to live to the age of 77.8, right? Wrong.

In mathematics, expectancy is a term used to describe the expected future value of something, based on current knowledge. For example, if you flip a coin 10 times and you win $1 for heads and lose a $1 for tails, the expectancy for this game is $0 because you expect, on average, an equal number of heads and tails.

So life expectancy then is the expected average lifetime of someone born today, based on what we know today – i.e. the death rates for today. The way they calculate this (and have since the 17th century) is by using life tables. Life tables give you, based on your current age, the probability of living one more year. For example, they tell you that if you were 39 in 2004, that you had a 99.82% chance of making it to 40.

The problem is, to calculate the 77.8 life expectancy figure for 2005, they’re applying those chances of someone making it from 39 to 40 in 2005, and projecting them 39 years in the future to calculate future survivability. So, 77.8 is really a fictional number that says that for someone born in 2005, if death rates at a given age were to remain as they were in 2005, this is how long they’d live on average.

We can probably all agree that it’s likely a lot of things are going to change in the next hundred years that will impact mortality rates. For example, there may be some big scientific breakthroughs on cancer or heart disease, there could be another world war or infectious disease pandemic, or we could be attacked by aliens…

Either way, life expectancy is not the same as expected lifetime.

Life Expectancy vs. Actual Lifetime

So if life expectancy is a projection of present knowledge on future longevity, we should be able to see how far off these figures were. For example, life expectancy for someone born in 1900 was 49.2; what was their actual average lifetime?

As I was trying to find actual longevity information, I came across a text book called “Development Through Life” by Newman & Newman that said that current life expectancy values are calculated using life tables, whereas life expectancy values for someone born in 1900 are now based on actual rates of death. This completely confused me because it implied that life expectancy was a dynamic number. That somehow life expectancy values from previous years would be recalculated using actual death rates. This would also imply that comparing the life expectancy for someone born in 1900 vs. someone born in 2000 would be completely bogus because we’d be comparing apples and oranges.

Fortunately, this assertion doesn’t seem to be true. Going back to the life tables from the CDC published in 1900, the numbers appear the same as the numbers reported for 1900 today, so I’m not sure what Newman & Newman were talking about…

In the end, I couldn’t find the numbers I was looking for, so I calculated them myself. To estimate the actual average lifetime for someone born in 1900 you can incrementally use all the life tables produced over the last hundred years because those life tables are calculated based on actual death rates for that year. For example, if you managed to survive to the age of 40, then the life tables from 1940 for someone aged 40 will tell you what the chances were of living to the age of 41. The biggest limitation to this approach is we can’t control for things like immigration and migration. Oh well, c’est la vie.

From my calculations, the average lifetime for someone born in 1900 was actually something like 55 years, rather than the original life expectancy of 49.2. Notice that over time, average lifetime seems to consistently be about 10 years longer than life expectancy.

[Note that the lines converge because as we get closer to the present, more and more people are still alive, which means I had to use more and more life table data rather than actual death data. As we progress into the future, I expect the average lifetime to retroactively creep as people continue to live beyond their original expectancy (as least as long as life expectancy continues to rise).]

Life Span

Life span usually refers to the maximum lifetime of a species. So, given that life expectancy is going up, you might ask if human life spans also being extended? It doesn’t appear so. The maximum life span for humans still seems to be about 110 years.

So the fact that my grandfather lived to the age of 94 wasn’t really statistically extraordinary; it was just a lot less likely than me living to the age of 94.

Usefulness?

So now that we understand life expectancy, what can we do with it? You and me personally, probably not much. The fact that overall life expectancy was 77.8 years in 2005 is pretty meaningless because it’s a composite number for everyone alive in 2005. It’s not that useful for a new baby, because the figures don’t attempt to predict the future. And it’s not relevant to someone born 40 years ago because how do you combine it with the life expectancy from 40 years ago? The number might as well be 75, 80, or 85.

But the change in the expectancy figure year to year can tell us something. Namely, if life expectancy is going up, it tells us that we’re all currently, on average, living longer – which is probably a good thing (assuming we have reasonable quality of life).

What about the fact that the life expectancy for someone who was 80 in 2005 was 9 years? Medical science isn’t likely to change significantly in the next 9 years, so the number is at least relevant. That said, your remaining lifetime at that age is probably more heavily affected by your current health rather than these general averages, so maybe that’s not all that useful either…

What about retirement? Can you make financial plans using these life expectancy numbers? If you do, you may be in for an unpleasant surprise… If the current trend continues, life expectancy will continue to under-estimate actual lifetimes. Life expectancy was off by 6 years for people born in 1900. How far off will it be for your generation?

[Content © 2008 SorryToConfuseYou.com, All Rights Reserved.]

Why Do People Have Gaping Blind Spots?

As I discussed previously, cognitive dissonance can cause us to rationalize and justify all sorts of strange beliefs and illogical decisions, but it has other effects as well.

Recall that cognitive dissonance causes us to deal with new incompatible information by either discarding our initial belief, or by dismissing the new information. It turns out that our brain has a strong preference for the latter. It would much prefer a stable set of beliefs rather than a constantly changing set. That way, the world seems to make more sense. The problem is, this can lead to an effect known as confirmation bias.

Professional Bias

As Carol Tavris & Elliot Aronson describe in their book Mistakes Were Made (But Not By Me), confirmation bias causes us to more readily accept information that confirms what we already know, and more likely to ignore or rationalize away information that isn’t compatible. We see what we want to see. It’s just another way the brain avoids cognitive dissonance.

The biggest problem with confirmation bias is that those with the strongest beliefs are those that are most likely to be affected by it. For example, all the big name experts in a particular field are some of the least likely people to be able to change their minds and admit to mistakes. Cognitive dissonance is strongest in them because they have the most to lose. In many cases, they’ve invested years or decades of their lives into an idea, so they’re not likely to want to admit that they wasted that much time on something that’s wrong – they’re supposed to be “experts”…

George Bush is a poster boy for this outcome. The more things go wrong in Iraq, the more he believes that it was the right thing to do, the more he comes up with new justifications…

Selective Memory

Cognitive dissonance also affects your memories. We like to think that our memories are accurate and objective, but they’re not. It’s not so much that we forget things, as much as we seem to remember ourselves more favorably or alter events to better fit our beliefs – i.e. we are all revisionist historians!

One of my first experiences with this process was late in my late teens – another teen and I had an “altercation”. A few hours later we were asked to recount the events as we remembered them. Incredibly, his story was completely different (and incompatible) with mine. It could have been he was lying to avoid getting in trouble, but I don’t think so. I think his brain had colored his memory and generated rationalizations for his actions in order to justify his bad behavior. I think he was describing events exactly as he remembered them. In the end, neither of our stories could be proven so it could just as easily have been me revising history. Either way, it was an eye-opening experience as to the malleability of the “truth”.

Selective memory also affects how we record history. There was a controversy a few years ago with an exhibit at the Canadian War Museum about the bombing of Germany in the World War II. The original text on the exhibit read:

“The value and morality of the strategic bomber offensive against Germany remains bitterly contested. Bomber Command’s aim was to crush civilian morale and force Germany to surrender by destroying its cities and industrial installations. Although Bomber Command and American attacks left 600,000 Germans dead and more than five million homeless, the raids resulted in only small reductions of German war production until late in the war.”

Seems perfectly reasonable to me… But some people were upset by it and asked (and eventually succeeded) to have the text changed to:

“Thousands perished in the raids and millions were left homeless. While these numbers are very large, they pale in comparison to the genocide perpetrated…by the Germans and their proxies.”

Mistakes were made, but theirs were worse. Who writes history? The winner of course…

Self-Fulfilling Prophecies

Why do good things happen to people with high self-esteem, and bad things seem to happen to people with low self-esteem like a big self-fulfilling prophecy? They don’t actually, it’s just how we remember things. If you have high self-esteem, you expect good things to happen to you – so when bad things do happen, confirmation bias shields you from it and you quickly forget the bad and only remember the good. The opposite would be true for people with low self-esteem, who will wallow in their perceived misfortune. It’s not positive thinking that brings us good things, it’s positive remembering that does.

We can’t actually change the way our brains work, but we can learn to recognize when they are playing tricks on us…

[Content © 2008 SorryToConfuseYou.com, All Rights Reserved.]

How Can People Justify Ridiculous Beliefs?

As I discussed previously, truth seems to be subjective and personal rather than objective and universal. But beyond that, we always seem to have reasons and justifications for our beliefs, even when those reasons can seem utterly ridiculous to others. For example, tell me if this sounds familiar:

“I was talking to so and so, and we got into an argument over such and such because they were completely obstinate. They absolutely refused to listen to logic. It was totally unbelievable.”

Why does this happen?  Why are people so irrational sometimes? Why do people never seem to say:

“You’re right, I’m wrong. Thank you for showing the error of my ways.”

It turns out, the problem is in how our brains process information.

Dissonance

As Carol Tavris & Elliot Aronson describe in their book Mistakes Were Made (But Not By Me), when our brain is presented with new information that conflicts with something we already believe, our brains have a problem. This state is called cognitive dissonance. Our brains don’t want to stay in this state because it wants the world to be logical and orderly. So our brain essentially has two choices, discard our initial belief, or dismiss the new information.

The most interesting part of the cognitive dissonance resolution process is when we dismiss new information, it’s not good enough to simply dismiss it outright, our brains need some reason to dismiss it. This is why we end up rationalizing or justifying our decisions. It’s not something we do consciously; our brains do it for us automatically.

For example, when we make a mistake it can cause cognitive dissonance. I’m a smart / competent / skilled person, how could I make a mistake?  To resolve the dissonance we’ll find some excuse – like “it wasn’t my fault, it was because <insert lame excuse here>”, even when it was clearly our fault.

How about smoking? It’s nearly universal believed that smoking cigarettes is harmful (how harmful is still up for debate), but there shouldn’t be any good reason to smoke anymore, right? Ask any smoker why they haven’t quit yet and they’ll have a fine list of rationalizations:

• “I don’t inhale”
• “I’ve cut back recently”
• “The scientists exaggerate the danger”
• “I only smoke when I drink”
• “I’m too busy right now, I’ll quit next month”
• “It helps me relax”
• “It prevents weight gain”

What about personal conflict, like domestic violence? If the abuser believes themselves to be basically a good person, then hurting someone they love will cause dissonance:

• “They provoked me”
• “They deserved it”
• “They’re worthless and lazy”

What about military conflict? In a war, who are the good guys and who are the bad guys? Do you think the enemy really think of themselves as evil? Not usually, but we rationalize killing them by demonizing them and whatever atrocities they’ve committed.

Indoctrination

The other interesting part of our rationalization process is the effect can be cumulative. Once we’ve made a decision, it’s hard to undo it, especially the difficult ones. Our brains will make sure we have a justification for that decision so that we won’t forever be worrying that we made the wrong one. Over time, that initial decision gets reinforced to the point where we can’t imagine ever making the opposite decision, even when it was a toss-up originally.

For example, whenever we argue about something, the longer we argue about it, the more we’re going to become entrenched in our belief, even if we’re obviously on the losing side. Not only are we defending our belief now, but also the time and effort invested trying to defend it.

This also how people get brainwashed (or indoctrinated if you prefer).

How do you turn a normal, well-adjusted person into a devout cult member? How do you teach someone to be an effective soldier? How you get someone involved in illegal activity? A little bit at a time. Once you get the ball rolling, self-justification will do the rest.

For example, if you told someone walking down the street that aliens are coming on a spaceship to save us because the world is going to end, they’d laugh in your face. But if you indoctrinate them slowly over time, you can get seemingly normal people to leave their jobs, their spouses, and to give away all their possessions.

Obviously some people are more easily influenced than others, but don’t assume you’re immune. Anyone can be turned into a completely different person under the right conditions. The brain is a funny thing. Our ability to self-rationalize is extremely beneficial because it lets us sleep at night. Just try to avoid the slippery slope…

[Image: Peter Arno]

[Content © 2008 SorryToConfuseYou.com, All Rights Reserved.]

Canada’s New "You-Can-Still-Call-Me" List

Canada is finally getting its own “do-not-call” list this fall, and with it, the promise of a quiet evening at home, or so the theory goes… I haven’t investigated thoroughly, but the Canadian version looks very similar to the American version. So I ask, how effective are these do-not-call lists? Could they be more effective?

The biggest flaw I see is the exemption list is too long. Who do you think calls me most frequently? Everyone that’s on the exemption list, of course:

• Charities
• Political parties
• Pollsters
• Newspapers seeking subscriptions
• Businesses with whom I have an existing business relationship

These things do tend to go in waves, but I suspect that 80% of the unwanted calls I get are from groups on the exemption list. For example, many of the calls I get are from companies with whom I do business already who are trying to upgrade me, or cross-sell me one of their 462 other products and services. The banks, cable and phone companies seem to be worst for that kind of thing.

The one obvious difference from the American version is that the Canadian version has an exemption for newspapers. The newspaper lobby must be stronger in Canada than in the U.S… Why should they be allowed to sell me something, but no one else can?

In the end, I think these lists are better than nothing, but I think they could be better. For example, how about:

• A “don’t-waste-your-time-calling-me-I’m-not-going-to-talk-to-you” list, which would apply to everyone, unless you’re calling me about problems with my existing service
• Require all corporations and organizations (for profit or not) to have their name show up on call display so we can screen our calls intelligently

Just a thought. In the meantime, I’ll continue ignoring most of my phone calls…

[Image: www.freeimages.co.uk]

[Content © 2008 SorryToConfuseYou.com, All Rights Reserved.]