The Blog

Trump Supporters Linked with Having Small Penises

A 69 year old man’s penis captured America’s attention in last month’s Republican debate. Donald Trump broadcast the size of his penis on national television in a response to Marco Rubio’s comment on his small “hands”: If they’re small, something else must be small.

Lifting his hands from the podium, Trump declared to the country, “Look at these hands! Are these small hands?” He added, “I guarantee you, there’s no problem.” As an indication of the importance of the topic, the media responded with extensive coverage of the moment for weeks.

Clearly, penis size is an important attribute. As the comments by Trump and Rubio indicate, the matter at hand isn’t just about size—it’s about the link to a many other skills and capabilities. What kind of skills is penis size connected to? Could it be ability in business, confidence, leadership? What else?

To find out, we studied over 1,400 people across the country to better understand the relationship between penis size and various skills and attributes.

Not everyone may agree on how many inches constitutes a small or large penis, so to measure the means, we used a scale that measured magnitude instead of inches. Positive numbers indicate largeness while negative numbers indicate smallness.

Men with large penises were:

  • more confident (41.78)
  • more likely to ask for the phone number of a person more attractive than themselves (30.98)
  • better lovers (30.12)
  • and generally better at sex (29.34)
  • with a higher sex drive (27.7).

Taking attributes related to sex out of the picture, the top five attributes become:

  • being more confident (41.78)
  • more willing to ask for an undeserved pay raise at work (21.76)
  • being more optimistic (19.04)
  • and taking more risk by both not fearing walking home at night in an unsafe part of town (19.02)
  • and by engaging in dangerous recreational sports (17.94).

The top 5 attributes men with small penises exhibited were:

  • voting for Donald Trump (-16.2)
  • being religious (-11.9)
  • more inclined to gossip (-9.54)
  • being good at math (-9.64)
  • and driving a large car (-8.36).

We also asked our participants to report their actual penis measurements and found an interesting distinction along political party lines. Democrats and Republicans equally inflated their size by adding on an extra inch compared with the national length average, but Republicans reported significantly larger ball sizes (11.5) than did Democrats (6.04). Do Republicans really have larger balls or do they only believe they do? This is an important question for future research.

One final note: While Donald Trump supporters seem to have smaller penises, it is important to note that this initial research focused on the size of erect penises. Donald Trump never made it clear (and interestingly no journalist asked him) if he was referring to the erect or flaccid size. Regardless of what state of penis Donald Trump had in mind, since men spend most of their days with a flaccid penis, the question about the size when flaccid is just as important, if not more important, and we hope to study it in the years to come.


A Summer internship at CAH

If you are a student and want to try something different this summer, check this out:

Apply for the Summer Internship in Behavioral Economics at Duke

Ask Ariely: On Interesting Incentives and Buying Bitcoins

Here’s my Q&A column from the WSJ this week  and if you have any questions for me, you can tweet them to @danariely with the hashtag #askariely, post a comment on my Ask Ariely Facebook page, or email them to


Dear Dan,

Ratings systems for different services often aren’t driven by incentives. One example: Instead of just rating Uber and Lyft drivers after they drop us off, what if their ratings were based on the size of the tips they got? In such a system, drivers who consistently received larger tips would get higher ratings; those who were penalized would be seen less favorably. Wouldn’t this be better than the current rating system?


Would you really give a bad tip to an annoying driver who had just dropped you off at home and knows where you live? (I am partially joking here, but I do wonder whether tips for taxis are higher when people are coming back home.)

Like other pay-for-performance approaches, your proposal for a tip-based ratings system would raise a lot of problems. First, discretionary payments such as tips reflect satisfaction, but they also reflect wealth and price sensitivity. Basically, some people care less about money and are likely to give higher tips than more price-sensitive people. Since the wealth and the price sensitivity of the passenger aren’t a precise reflection of the quality of the driver, your suggestion would just replace one flawed system with another. A second, even more serious problem: Drivers would get an incentive to drive more in areas where people are less bothered by high prices, thereby providing worse service to other people who might need transportation more. Finally, what would stop drivers from giving cash back to passengers who gave them larger tips—returning some of the extra money but gaining reputation points in the process?


Dear Dan,

Some time ago, I bought some bitcoins. In just a few months, their value increased by 1,000%. They’ve just kept rising and are now about 4,000% higher than when I originally purchased them. My original investment is now worth more than $100,000—a substantial amount of money for me. Should I sell or hold onto them and hope for further increases?


It is hard for me to say whether this is a good investment or not, but here’s a more rational perspective for examining the question: Simply ask yourself if you would buy these bitcoins now, at their current price. If your answer is yes, you should hold onto your investment and maybe even buy more. But if your answer is no, it means that you don’t really think that the expected increase in value is worth the risk, and you should sell.

The more general point here is that our investment decisions should be about what we think the future will hold (hard as that is to predict), and we need to work hard to overcome the influences of our past actions. No matter what you purchased a given investment for, and regardless of what it is worth now, you should make your decisions only about where you think this investment is headed.

One last piece of advice: If you do decide to sell your bitcoins, don’t look up their value afterward. Yes, if the value drops, you’d be a bit happier that you sold, but if the value rose, your misery would be much higher—so resist the urge to check.

See the original article in the Wall Street Journal here.

Ask Ariely: On Fair Friends, Channel Choosing, and a Heartbreak Diet

Here’s my Q&A column from the WSJ this week  and if you have any questions for me, you can tweet them to @danariely with the hashtag #askariely, post a comment on my Ask Ariely Facebook page, or email them to


Dear Dan,

I’m organizing a long weekend of skiing with 10 friends who have very different financial situations. I’d like everyone to be able to pay what that they’re comfortable with, and I also want to avoid creating an awkward social dynamic. I considered charging everyone a low base amount and then asking the wealthier friends to pay extra, but that doesn’t seem quite right. What’s the best way to divide up the cost?


There are three considerations here. The first is to make sure that the amount people pay covers the cost of the trip. The second is to get everyone to feel that the payment is fair. And the third is to make sure that the payment procedure doesn’t harm your relationships and hamper the fun.
My guess is that if you approached a few of the wealthier people and asked them to pay extra, this wouldn’t seem fair and would change the social dynamic. If the wealthier individuals paid more, they would probably want to get the better rooms in the rented house, they might not feel the same need to help with meals and cleanup, etc.
I would try to overcome these challenges by setting up a rule that said: If your annual salary is X or less, please contribute Y; if it is up to 1.5X, please contribute 1.5Y.
This isn’t the same fairness rule as equal pay, but it is still a fair rule. I would add some social framing to this, reminding your friends that you all value the shared experience and the joint company, and it is important that everybody participates and isn’t stressed about the trip. I would also make the payments private, so that no one knows how much other people are paying.
The challenge with this approach is that you probably don’t know your friends’ exact incomes, and some of them might not pay what they should under your scheme. I suggest that you take this into account by adding an extra 10% to the price. And if your friends surprise you by being honest, have a nice party on the last day of the trip.

Dear Dan,

Why do I still listen to the radio and watch live TV when I have access to all the same content from different streaming services, which lets me skip what I don’t like and more easily change my experience?


One possibility is that you are listening to the radio and watching live TV because you don’t want to have the ability to switch. When you just experience something that cannot be changed, you are more likely to get into the flow and fully enjoy it. By contrast, when you are continuously monitoring the experience and asking yourself how happy you are, it can be exhausting, ultimately taking away from the sense of immersion. Sometimes the freedom to choose among options isn’t a recipe for happiness.


Dear Dan,

I recently experienced some turbulent emotional times, and I realized that I was eating a lot of chocolate and gaining weight. I am now wondering if chocolate really has mood-improving powers, as many people seem to think, or if I just gained weight for no good reason.


Some research has found that chocolate can in fact boost your mood—perhaps due to compounds found in cocoa. Interestingly, women seem to be more likely than men to eat chocolate to try to boost their moods. That could mean that experiencing some heartbreak is a good diet for men but not for women.

See the original article in the Wall Street Journal here.

Help with an email study

Dear friends,

For many of us, email is a source of joy and stress –  we learn a lot from it, but we also never seem to be able to keep up with our inboxes.  And in today’s world, it’s likely that we’ll be using email more and more.  A project I’m working on right now is to try to better understand how we work with email, with the hope of figuring out what is broken and what we can do about it. 

My first step is to research how we currently use email.  If you’d like to help me by completing a 5-minute survey, please contact me at  Survey participants will not only receive my gratitude, but will also be entered for a chance to win any of my books, a 30-minute chat with me, or $500. 

Irrationally yours,


The Costs of Staying in Hospital Too Long

Dear Dan,
I’m a physician, and it seems to me that people often stay in the hospital for too long. (One piece of evidence: Many more patients get discharged from the hospital on weekends.) Prolonged hospitalizations cost a lot of money and mean that beds aren’t available for people who need them. How can we change this?

Think of three parties involved in decisions about staying an extra day in the hospital: the doctor, the patient and the family. All three would benefit from having patients discharged before the weekend: The doctors have fewer patients to deal with, the patients get to return to their loved ones, and the families can stay home rather than making one more hospital visit. Maybe we should try to make every day in the hospital feel like Friday.

Here’s a more concrete idea: Why not take one channel on the hospital’s internal TV system and dedicate it to people’s bills? The channel could present patients with real-time information about their bill, showing it rising with every meal, treatment and round of medication. It could also show the charges expected over the next 24 hours. My guess is that this change would spur people to leave the hospital much sooner.

Dear Dan,
How can we encourage people to eat less meat? Lots of people consider it cruel to kill animals and identify emotionally with vegetarians but still choose to eat pork, chicken and steak.

Sadly, our choices—moral and otherwise—often aren’t the result of what we know but what we feel, and feelings have their quirks. In my field, there is something called the Identifiable Victim Effect, which shows that people can care deeply about a single, specific tragedy (such as the death of one Syrian refugee) yet care little about vast atrocities involving thousands or even millions of people (such as the Syrian crisis).

A similar principle applies to the ways we think about treating (and eating) animals. During a 2001 outbreak of foot-and-mouth disease in the U.K., the authorities had more than 2 million farm animals slaughtered near infected areas. It was tragic for the animals, the farmers and the British economy, but the decision didn’t produce much public complaint—until one day, when newspapers published front-page photos of a cute little calf in Devon that survived the killing. That picture spurred a public outcry against the wholesale slaughter and, according to the Associated Press, may have helped produce “a change of heart by the British government” that ultimately helped end the killing. The abstract concept of slaughtering legions of cows, pig and sheep did nothing, but the adorable face of one calf made people sad and drove them to take action: the Identifiable Victim Effect at work.

So your best bet may be to wait for the ideal opportunity for a pro-vegetarianism campaign, ideally involving one particularly cute animal.

Meanwhile, you could encourage people to read Jonathan Safran Foer’s “Eating Animals,” which describes in vivid detail the conditions in which the creatures we consume are forced to live and die. Reading it made it hard for me to even look at a burger without thinking about what happened to the cow that it came from.

Dear Dan,
What’s the best love note one could write?

The ideal message would show confidence, deep desire, a capacity for romance and optimism about your shared future. With all these in mind, I’d suggest, “Would you give me the opportunity to sweep you off your feet?”

Help us test a new email app

There is no question that email is one of the most important communication tools. It is also clear that it is a monster that is taking over our life and attention.


A few years ago in an attempt to reduce my own communication overload, we created Shortwhale (, which asks the sender to classify the email before it reaches my inbox. Now, I am attempting to reduce email load and increase productivity further. Together with a fantastic team we created an email app (iPhone only at this point) that is aimed at helping people better manage their email-life and the related stress.


So far I have used an early version of the app for a few months and I find it very useful. We are now ready to open this app for a few more beta testers who are interested in helping us figure out ways to fight the email challenge.


Below is a short video of the email problem and our approach, as well as a way to sign up to test the app (link:


If you are struggling with email and want to help us, please sign up – and thanks in advance .



A very Happy Valentine’s Day

And here is a talk I have posted before.  Some lessons about romance and love.  Some might even be useful.

Lots of love




Ask Ariely: On Experimental Explanations, Procrastination Punishments, and Server Strategies

Here’s my Q&A column from the WSJ this week  and if you have any questions for me, you can tweet them to @danariely with the hashtag #askariely, post a comment on my Ask Ariely Facebook page, or email them to


Dear Dan,

For some time now, I’ve been proposing different experiments at my company—experiments with the prices we charge, what we pay employees and the way we treat customers who call to complain. But the experimental approach that seems so successful for science bumps into substantial resistance within my company. Any ideas about how to make experiments more palatable in the business world?


Without knowing exactly why your colleagues are balking at the experimental approach, it is hard to propose a solution. But based on my own corporate experiences, I’ll assume that they are objecting to the idea that some people in your experiments will get better treatment and some will get worse treatment, which just seems unfair.
One of my colleagues at Duke experienced a related challenge recently. He asked a local urban high school if he could offer half the students a free lunch to see how it might influence their attendance and academic performance. In the spirit of experimentation, he wanted to randomly select which pupils would get the free lunch and which ones wouldn’t. The school found the suggestion repugnant: It seemed offensive to select some kids and not others.
My colleague waited a few months and tried again. This time, he told the school administrators that he wanted to give all the students the free lunch but could only afford to pay for half of them—and asked the school how to decide who would get the free lunch. And what was their suggestion? You guessed it: to pick the kids randomly. As this story illustrates, equity is a major obstacle to executing experiments. But if you can figure out how to frame them as fair, they might become more palatable.


Dear Dan,

I’m a philosophy professor, teaching metaphysics and philosophy of language. What’s the best policy for penalizing students who hand in coursework late, with an eye on preparing them for the world of work?


If the goal is to prepare students for life, I would start by creating a penalty system with a continuously increasing punishment—say, cutting their total grade by 3% for every day of delay. This largely resembles the penalties that adult life imposes: Even for things with very clear deadlines, like taxes, you can be late—but there’s a penalty for doing so, and the longer you wait, the larger it becomes.
Since you’re interested in helping your students more generally, you could also help them learn how to better plan their time. Students procrastinate, routinely and repeatedly, and they rarely seem to conquer this pattern. You could take a more active role in helping them create virtuous habits of planning and time management, perhaps by helping them break down daunting tasks into manageable sub-tasks and showing them how to schedule these in their calendars. Such ploys won’t teach them philosophy, but by dedicating some class time to such things, you might teach your students some important life lessons—and free up more time for them to read Aristotle and Wittgenstein.


Dear Dan,

I’m a server in a New York City restaurant in New York, and I want diners to trust my recommendations and leave me larger tips. Any advice?


As soon as you hand them the menu, tell them that you strongly recommend they avoid the branzino special (or any other very expensive dish). By demonstrating that you’re willing to steer them away from a pricey entrée, they’re more likely to think that you truly care about them, trust your advice and tip you more.

See the original article in the Wall Street Journal here.


Ask Ariely: Surge Charges, Moving Costs, and Expiration Dates

Here’s my Q&A column from the WSJ this week  and if you have any questions for me, you can tweet them to @danariely with the hashtag #askariely, post a comment on my Ask Ariely Facebook page, or email them to


Dear Dan,

I use Uber more and more these days, but I feel bad about using it when they slap on surge pricing rates, as they seem increasingly prone to do. Even with the surge rates, Uber is often cheaper than taxis—so why the mixed emotions?


Your question contrasts two sides of pricing: supply and demand, on the one hand, and fairness, on the other. Surge prices occur when users’ demand for rides outstrips the supply that existing drivers can provide—at which point Uber adds a multiplier to each fare to encourage more drivers to work and, simultaneously, to discourage more frugal passengers from asking for rides.
From an economic perspective, surge pricing is a beautiful, two-front solution to this supply/demand mismatch. But it still feels unfair: When you take an Uber at the regular rate to start your evening and are suddenly told that the trip home will be three times more expensive, you feel blackmailed.
To think about the fairness issue, imagine that you’re very thirsty. The only lemonade stand in the area knows this and charges you three times as much for a glass. Something not too different took place some years ago in Brazil: On hot days, Coca-Cola decided to increase the prices in their vending machines. People hated it, much as you find yourself reacting to Uber’s surge rates.
This fairness question is central to Uber’s business model. For its long-term sustainability, it needs to handle the problem in a way that doesn’t feel unfair. Perhaps a loyalty program?


Dear Dan,

My partner and I make a reasonable income, and we’ve been able to save some money over the years. We can afford to move to a more expensive neighborhood, but we aren’t sure if this is the right way to spend our money. What do you say?


I’d be cautious about moving to a pricier area. We tend to compare ourselves with our surroundings, and our happiness stems directly from those comparisons. If the people around us drive Hondas, we feel good in a Honda; if those around us drive Audis, our old Honda will make us cringe.
Moreover, we quickly become accustomed to the fancy new car and derive less excitement and fun from it. This phenomenon is called the “hedonic treadmill”: We continuously chase prestige, thinking it will make us lastingly happy, but we rather quickly revert to our pre-purchase level of happiness.
So you should be careful when trying to figure out the benefits of moving. Right now, you’re probably overestimating the value of a move; six months afterward, its value is likely to seem lower. As a practical shortcut for all this, you could assume that the value of moving is only half of what it seems right now—and ask if you’d still move. If the answer is still yes, go for it; if it is no, stay put, and look for other ways to spend your money.


Dear Dan,

What’s the best way to improve the quality of marriages?


The No. 1 enemy of relationships is being taken for granted. So I would set up marriages to expire automatically every five years and be renewable only if both parties opt in for another five-year period. Sure, this setup would mean that more people separate (you asked about the quality of marriages, not their longevity). But spouses would have to think more carefully about their partners, take them less for granted and thereby strengthen their relationships.

See the original article in the Wall Street Journal here.