Bryan Caplan  

The Mosquito Bite Analogy

The Silence of the Bets... Choice Architecture in the Caf...
Free-market economists often lament the difficulty of communicating their ideas to a popular audience.  Why?  Because the free-market prescription is often, "Government should leave the problem alone.  Trying to fix it only makes it worse."  How is anyone supposed to sell such counter-intuitive ideas?

I've think I've got a way to make the counter-intuitive intuitive.  Just say: "Many social problems are like mosquito bites."

When a child gets a mosquito bite, every adult gives him the same advice: "Don't scratch it!  Touching the bite only makes it worse."  The child's standard response: "But it itches!"  The adult rebuttal: "Sure it itches.  But now that you've got a mosquito bite, this itching is the best outcome you can hope for.  Don't blame me, I'm only a messenger."

This mosquito bite analogy doesn't just make the case for do-nothing solutions easy to understand.  The analogy also instantly answers the "If your ideas are so great, why are they so unpopular?" objection.

No one seriously denies that scratching mosquito bites makes them worse.  But almost all children - and most adults - keep scratching.  Why?  Because, as Bastiat would say, "good is apparent to the outer eye" while "the harm reveals itself only to the inner eye of the mind."  To keep your hands off your bites, you must constantly remind yourself that your impulses are folly.  No small task.  The rarity of do-nothing policies is no more puzzling than the rarity of keeping your hands off your mosquito bites.

To be sure, there is one fundamental difference between mosquito bites and social ills: People have a strong incentive to control their urge to scratch, but no incentive at all to control their urge to vote for whatever superficially sounds good.  After all, if an individual focuses on the long-run costs of scratching bites, he personally captures the benefit.  If, in contrast, an individual focuses on the long-run costs of government solutions, nothing changes.  That's democracy for you.  For all his brilliance, Bastiat suffered under the same short-sighted policies as every other citizen of France. 

The mosquito bite analogy has two big lessons - one hopeful, one depressing. 

The hopeful lesson: There is a better way.  Counter-productive "solutions" are all too real.  Adults scratch their bites, and citizens vote to make bad situations worse.

The depressing lesson: The better way is unlikely to be adopted.  Many adults keep scratching their bites even though they personally bear the costs.  What are the odds that adults will stop voting to make bad situations worse when they can make all the mistakes they want, free of charge?

HT: My dear son Simon, whose legs are covered with well-scratched mosquito bites despite my advice.  Well, at least he has the good sense to welcome mosquito repellent.

COMMENTS (23 to date)
Elmer Fike writes:

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Jay writes:

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Ted Levy writes:

"Well, at least [Simon] has the good sense to welcome mosquito repellent."

Ah, but Bryan, who's paying for the mosquito repellant?

F. Lynx Pardinus writes:

I'm dubious that referring to serious social issues as "mosquito bites" is going to impress the general population.

Philo writes:

Wonderful mosquito repellent! It stops the problematic situation from arising, and thereby it saves us from our bad impulses. If only we could somehow forestall those unfortunate situations that make people wrongly seek a government solution. But there is no such repellent; indeed, many of these situations are brought about by the government itself.

Steve Fritzinger writes:

I have another idea, use the children's song about the old lady who swallowed a fly. If you've swallowed a fly, swallowing a spider only makes things worse, even if you then swallow a bird, a cat and a dog.

The final line of the song is appropriately pessimistic, "I knew an old lady who swallowed a horse. She's dead, of course."

JdL writes:

No one seriously denies that scratching mosquito bites makes them worse.

I do. As far as I can tell, you're repeating an old wives' tale.

HT: My dear son Simon, whose legs are covered with well-scratched mosquito bites despite my advice. Well, at least he has the good sense to welcome mosquito repellent.

What repellent is that, DEET? You might want to research its toxicity before blithely applying it to your son.

Nice try, but I give this column a 'D'.

guthrie writes:


Scratching increases histamines, which are what cause the itch in the first place. Plus, scratching can produce scars. This same advice is used for poison ivy rashes.

Bill Kaplan writes:

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Tom E. Snyder writes:

@Steve Fritzinger,

Thanks very much for the suggestion. I found a YouTube version and have just incorporated it into one of my PowerPoint presentations for my ECON 1301 classes this Fall.

Keith writes:


Your comment was bizarrely vitriolic. Why assume it's DEET? It could be anything, like maybe icaridin.

Rick writes:

I like it. Now how do we fit it on a bumper sticker?

In the mosquito bite analogy, Bryan continues a common a libertarian quest. This is the quest to find some one thing to say to statists which will finally start them thinking, the quest to find a "silver bullet".

I've been looking for a silver bullet for 35 years. So I'm starting to wonder if there may be no such thing. Right now I am feeling skeptical that it has ever happened that an electorate, upon receiving an education, has fundamentally changed the way it voted.

So here is my question. Is there any evidence that silver bullets exist? evidence of the sort that shows that an electorate changed its posture of voting after a silver bullet came into circulation?

Capt. J Parker writes:

Aha! True scratching a mosquito bite with your fingernails is going to draw blood and may lead to a minor infection. BUT, if you rub the area for several minutes with a mild abrasive like that found in abrasive hand cleaners sold in auto parts stores then the mild irritation will exhaust the histamine producing capacity of the affected area and relieve the itching for one to two hours. I think the analogy probably still works you just need to believe that government is incapable of this level of sophistication.

mike davis writes:

Not so sure I like the analogy for two reasons, one serious and the other kind of random.

Serious reason: It comes uncomfortably close to confirming the meme popular with certain progressives that their opponents’ policies are grounded on a notion that economic pain is good. Remember the backlash that Michael Kinsley suffered a few weeks ago when he suggested that maybe, just maybe Krugman’s foes were not pure evil.

Random reason: The whole “don’t scratch” thing is a puzzler. For obvious evolutionary reasons most stuff that feels good is good for us—we’re designed to eat when we’re hungry, drink when we’re thirsty and have sex, well, anytime we can. So why did our biology fail us when it comes to mosquito bites? I have done extensive research (ok, five minutes on Google) and kind find lots of folk wisdom (scratching spreads infection, messes with histamines… blah, blah) but no real empirical study or even any explanation of why it is good that we itch but bad that we scratch. I can make up as many stories about evolutionary advantage as the next guy, but before we accept the “don’t scratch” analogy I’d like to know if it’s even good advice for the kids.

MingoV writes:


No one seriously denies that scratching mosquito bites makes them worse.
I do. As far as I can tell, you're repeating an old wives' tale.
It's not an old wives' tale. Mosquito bites itch because a component of mosquito saliva is irritating. Scratching does nothing to fix this: the irritant is under the epidermis. Scratching greatly increases the likelihood of infection. The mosquito bite victim went through the period of itching, but now has a skin infection with redness, swelling, pus formation, and discomfort. It can take 2-10 days to eliminate the infection (that sometimes must be lanced). In someone with a poor immune system, skin infections can be dangerous.
-- a pathologist

Aaron Zierman writes:

Excellent analogy. The "cure" can indeed be worse than the disease.

Often the loud cry of "we must do something" is similar to "but it itches so bad". Advocating not to act is not heartless, it is the same as a parent not wanting their child to hurt more.

What is truly heartless is not taking the time to consider whether taking action is truly better than not taking action. To not act rashly in the face of a crisis, that takes real political fortitude.

Sadly, the incentives just aren't there for our politicians. As Rahm Emanuel so eloquently put it: "You never let a serious crisis go to waste. And what I mean by that it's an opportunity to do things you think you could not do before."

Hazel Meade writes:

I don't think it is very apt.

People don't just advocate policies because they have an irresistible itch. They believe they are good policies on a conscious level. Acting as if the advocacy of those policies is just a subrational itch is just going to seem condescending.

Personally, I think the problem is not that the argument for markets is counter-intuitive, but that certain basic arguments for markets run counter to some deep seated social norms (selfishness is BAD m,kay?), and the arguments for socialist policies are supported by those norms (sharing is good, m,kay?).

So the goal should really be to get people to resist the knee-jerk "sharing is good" reaction and to reframe the argument in terms of cultural norms people already support. For example, the flat tax gets a lot of support by virtue of the fact that there's a social norm that equal rules are fair. Similarly, the idea that regulations and subsidies can bias markets because the rules are different for different people strikes people as unfair. Instead of trying to get people to accept "greed is good", appeal to people on the basis of the essential fairness and equality of a market with simple, minimal, uniform rules.

JohnC writes:

Hmmm, I like the gist of the mosquito-bite analogy (and the "urge to scratch an itch" plays well; though comparing social problems to mosquito bites is something Romney might have said). But, what about an analogy to antibiotics (or other iatrogenic "solutions")? People demand them when they're not necessary (i.e., for the flu or minor bacterial infections); some doctors prescribe them anyway, even when they know they're not medically necessary, possibly because it feels better (for the dr. and the patient) to do something rather than nothing; and unnecessary use of antibiotics is bad for everyone, whether we use them or not (i.e., it helps create drug-resistant strains of bacteria). And there's a the notion of the allocation of scare resources, claims of differential treatment, etc.

Perhaps the pathologist from above can improve on this analogy.

ThomasH writes:

It is a good enough analogy for any problems that are of the relative importance of mosquito bites and which will in fact go away if the urge to "do something" is resisted (although I use aloe or calamine to reduce itching).

It does not seem to be a very good analogy for problems such as rising health care costs and the number of people who did not have health insurance, financial regulation that left institutions "too big to fail," high levels of unemployment during and after recessions, rising CO2 levels in the atmosphere, particulate emissions from coal-fired electricity generation, etc.

The correct course for Libertarians (or Liberals or Conservatives) would seem to be, taking into account that there ARE things that might be "done" that are worse than doing nothing, to propose cost effective ways of dealing with non-trivial problems.

In doing so, it is probably also helpful to argue as if those advancing solutions with which one disagrees are doing so in good faith and that the disagreement turns on differing estimates of the costs and benefits of the solutions and not from a deep ideological desire to "socialize the economy" or "protect the 1%."

Aaron Zierman writes:

I think some people are missing the point of the analogy.

It is NOT saying that nothing should ever be done. Of course there are plenty of real problems with real potential cures. However, far too often bad legislation passes because "we have to do something, anything". There are obvious political pressures to act without regard to the ramifications of said actions.

Sometimes, nothing is better than something. The point of the analogy is that simple truth. The idea that not acting is a viable option, perhaps even the best option in some situations.

Again, it is not saying to never do anything. I think that would be a poor reading of the analogy.

Aaron Zierman writes:

It reminded me of the second Keynes vs. Hayek rap video, where this exchange takes place:


So what would you do to help those unemployed?
This is the question you seem to avoid.
When we’re in a mess, would you have us just wait,
Doing nothing until markets equilibrate?


I don’t wanna do nothing, there’s plenty to do.
The question I ponder is who plans for whom.
Do I plan for myself or leave it to you?
I want plans by the many, not by the few.

MingoV writes:

@John C: "Perhaps the pathologist from above can improve on this analogy."

1. You have the flu, want to feel better, and ask your doctor for antibiotics. The doctor says, "Flu is caused by a virus, antibiotics don't kill viruses, giving antibiotics that aren't needed can cause harm to you and others.

2. You have a cold, want to feel better, and decide to take massive doses of vitamin C. Your pathologist neighbor says, "Cold viruses are not killed by vitamin C, so you're wasting money and you can experience side effects such diarrhea and bloating.

They're just variants of the same theme of doing something that feels good now despite negative consequences later. This theme is seen with eating too much, overusing intoxicants, putting off important tasks, calling in sick when healthy, shopping on impulse, driving 20 mph over the speed limit, etc. Each of these could be used to say, "This government policy is like eating too many tasty things, and then getting a stomachache and gaining weight..." Few people will change their opinions or behaviors after hearing or reading the analogy.

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