Is There a "Moral Molecule"? A Guest Post From Neuroeconomist Paul Zak


Neuroeconomics — generally viewed a combination of economics, neuroscience and psychology — tries to shed light on the biological elements of our decision-making. Why do investors do what they do? Why are some people stingy and others generous? What makes a consumer decide between buying a handbag and stuffing the piggy bank? Building on the work of behavioral economists, neuroeconomists have begun to apply their tools to these kinds of questions, often with illuminating results.

Paul Zak, a professor of economics, psychology and management at Claremont Graduate University, is founding director of the Center for Neuroeconomics Studies. Here’s a guest post he has written about his research on oxytocin — or, as he puts it below, “the moral molecule.”

Economist as Therapist
By Paul Zak

People make mistakes. Freakonomics documented many of the poor decisions people make on a regular basis. While I know none of you readers have ever made a bad decision, think of your brother-in-law’s investment in that scuba shop in Albuquerque. Or the geniuses at Lehman Brothers–not so wise. So, if we have such big brains, why do we make so many mistakes?

We’ll get to that in a minute, but since we do make mistakes with money, should economists get into the therapy business?

Richard Thaler and Cass Sunstein have come down strongly on the side of therapy in their book Nudge. Thaler, one of the founders of behavioral economics, has spent much of his career documenting the systematic mistakes people make. Thaler and Sunstein’s idea is to guide decisions using “choice architecture” that uses people’s biases to help them make better decisions.

There are at least two problems with this approach. The first is the slippery slope argument: Americans drink too many sugary sodas, so let’s tax them or make them harder to get. While this may enhance health, it is an affront to personal liberty. If you like Coke, do you want “choice architects” in Washington saying you can’t have them? What’s next, prohibiting hot dogs? The second problem is that knowing that people make poor decisions doesn’t get to the heart of the problem–why are they making these choices? Economics has no answer other than “they must like it.”

This is where neuroeconomics, a field I helped start, comes in. It uses the techniques of neuroscience to measure brain activity while humans and animals make decisions. This opens the “black box” behind economic decisions (and cognitive psychology) to reveal why people are doing what they are doing. Indeed, I began doing neuroeconomics studies in 2001 out of frustration–people in experiments could not tell me why they were making particular choices. By measuring brain activity, I could build better economic models by looking at the real reasons for decisions. We do this by measuring brain activity while people make decisions in MRI scanners, or measuring neurotransmitters in blood, or turning on or turning off parts of the brain using magnetic pulses or drugs.

Which is how I got into the therapy business. Well, at least what passes for therapy on TV, call it “theratainment.” I was recently (April 27, 2010) on the Dr. Phil show as part of a panel of experts discussing why men cheat on their wives and girlfriends. Hey, that sounds like real therapy.

Here’s why: my claim to fame is that I discovered that a hormone and neurotransmitter called oxytocin motivates us to trust complete strangers with money on the expectation that such trust will earn us a return. I did this first by taking blood from people in money exchange experiments (with collaborators Bill Matzner and Rob Kurzban). We found that the more money-denoting trust a person received, the more his or her brain released oxytocin. And the more oxytocin on board, the more the trustee returned some of the money he had received (which tripled in value) to the person who had trusted him. Oxytocin acts like a moral molecule, inducing trustworthiness. About 90% of people who had shown trust in a stranger were not disappointed — their trust was returned and they left the lab with additional money. This helps explain why we trust all kinds of strangers outside the lab.

Next, I shot synthetic oxytocin into the brains of hundreds of people using a nasal spray (no needles into the brain!). I found that oxytocin caused people to trust others with their money more; and to be more generous when asked to share money; and even to donate more money to charity. Oxytocin seems to change the balance between self and other. This is a huge issue in economics because traditional economics assumes people are selfishly motivated, even though this runs counter to a vast amount of evidence. Now we know why we are not all selfish: as social creatures we evolved a biological mechanism to motivate cooperation.

In other studies, I found I could inhibit prosocial tendencies. For example, I recently administered synthetic testosterone to men, roughly doubling their testosterone levels. This made the men in our study (compared to themselves on placebo) more self-focused and stingy with money, and more aggressive when given an option to punish someone who was being stingy towards them. Why? Testosterone inhibits the action of oxytocin.

Fast forward five years to Dr. Phil. Before my research, oxytocin was known solely as a reproductive hormone, released during sex and childbirth and sometimes called the “cuddle hormone.” Testosterone had been known previously to potently affect libido. My neuroeconomics studies (with the help of many collaborators) had gone further and shown that these hormones also change the brain’s cost-benefit analysis in powerful ways. The couple who appeared on Dr. Phil with me, Jose and Angela, were in trouble. Jose had cheated on Angela and was facing an imminent divorce so he agreed to come on the show. (Dr. Phil, quite ethically, pays for three months of therapy for guests on his show.) We experts were going to explain why men like Jose cheat and what he could do to stop making these selfish and shortsighted choices (Jose and Angela had just had a baby when he cheated on her).

I’m not sure if I and the other experts helped Jose and Angela, but at least we got to explain the science behind Jose’s behavior. I suspected that Jose had high testosterone levels — he took all kind of risks when skydiving and playing extreme sports because he enjoyed the thrills. Illicit sex was another thrill he sought out. His testosterone inhibited his “care-for-others” brain mechanism that typically motivates attachment to a spouse and love for a child; and now he was facing a divorce. Let’s see, risky behaviors leading to a downfall. That sounds a lot like what happened at a dozen Wall Street investment houses in the last couple of years. Maybe its time for neuroeconomics to be used in the design of regulatory policies.

Knowing why we do what we do is the first step to improved decision-making, and this is exactly the promise of neuroeconomics.


Yeah science! Now it's time to castrate him, because that's what Science says!

Rudiger in Jersey

When there is a moral decision, I consult my two little Me's. On my right shoulder is the Angelic Me; he is about 3 inches tall with a high pitched squeaky voice. He wears a white gown, has wings and a halo.

On my left shoulder is the evil twin; same guy, but he has a red complexion, lizard like appendages and claws, horns and a pitchfork.

They debate the issues back and forth and with my head. I turn and talk to my left shoulder and right shoulder and people leave me alone in the subway. Others do this with plastic earpieces and mobiles, but they are not very good.

But they are my conscience battling for control of my soul. It's like a cell phone phone conversation with God but with unlimited free minutes and no contract requirement. Such a Deal!


The first is the slippery slope argument: Americans drink too many sugary sodas, so let's tax them or make them harder to get.

No, sir. Their "paternal libertarianism" is about giving people nudges in subtle ways. To quote Thaler,

"Nudge-type policies would include things like displaying the fruit more prominently in cafeterias, posting calories in fast food restaurants (where the costs of doing so are low) or making ingredient labeling in grocery stores more prominent and user friendly."

They do not endorse "choice architects", and to quote Thaler again,

"I am not sure how we would have decided what to push for since Sunstein and I do not agree ourselves."


There are plenty of ways to do things like this - priming and default choices immediately come to mind.


Oxytocin may stimulate trust, but calling it a "moral molecule" seems erroneous. Trusting others is sometimes productive and sometimes destructive, sometimes moral and sometimes not. Sure, con artists may find their incomes enhanced if they can induce their marks to inhale a little oxytocin first, but what has morality got to do with it?


So did you spray Jose with oxytocin in a bid to save their marriage?

Should the SEC require all investment bankers and traders to get annual oxytocin shots when they update their broker/dealer or investment advisor licenses?

Maybe federal regulators should mandate the all firms must have a quota of 50% female traders in order to reduce risky behavior of high-testosterone males.

Rudiger in Jersey

The big impact of Oxytocin, a peptide molecule, is that nowadays most babies are being delivered on Monday mornings. Oxytocin is the magic bullet that stimulates the whole birth process. And with infusions, Obstetrician doctors can turn on birthing like a light switch. If Viagra is the beginning, Oxytocin is the end. Now you have a screaming demanding newborn for the next 20 or 30 years. And your doctor can enjoy his weekend in peace.

What does oxytocin do for morality? Or even physiologic water retention? We know a lot about serotonin and happiness or depression. But it is not a simple serotonin infusion that turns a frown upside down. IT is complex feedback regulatory loops and hormone exlcusion from the blood brain barriers, and selected transport and competitive inhibitions. It is never simple. There are 5000 chemicals in a drop of blood, the majority of we cannot fully explain signficance or actions.

Better to explain morality from childhood education and developement. One hormone doesn't pass the smell test. But I know a beer can turn a normal moral guy into a cad.



The question is not whether there are chemicals within us that push us in certain directions, give us certain propensities. Indeed, that much appears to be true.

Rather, the question is whether we are able to resist the temptations, whether we have any control at all. If so, then we remain morally responsible. If not, then we are determined by our body's chemical uniqueness and, thus, are amoral.

I like to think that no matter how much our bodies push us, there is something within us that can, if we really want to, say no.

Otherwise, thousands of years of moral philosophy just went out the window.

Bob W.

"Illicit sex was another thrill he sought out. His testosterone inhibited his "care-for-others" brain mechanism that typically motivates attachment to a spouse and love for a child; and now he was facing a divorce. Let's see, risky behaviors leading to a downfall."

Tiger Woods, anyone?


No matter what chemical makeup you have in your body your spiritual and moral compass are Homo Sapiens guides.

Bravery, sacrifice, charity, etc. are systemic to human beings worldwide and through the ages and it has nothing to do with science to quantifying these attributes.


@AaronS that is a false dichotomy. hard determinism does not necessarily indicate the lack of free will.

if you want to examine in detail these arguments:

Robyn Goldstein

You asked a question and so I will answer it in the specific way in which it was not found. The answer, in terms of the human experience is No.

There is a modern, an ancient and possibly a real post-modern version of the story as yet to be told. The ancient version can be found in how the original organization of the bachelor house was formed in China. And it was formed by a prince who created a permanent following by convincing the warriors (his original followers) of an orderly transition from this world of family life into the next. They believed it.

The modern version was discovered in the course of a conversation with the mother of a fellow student of my daughter some 12 years ago. The boy (an only child) wanted a dog. The parents bought him a dog. The dog pooped all over the house and began to destroy the furniture. The mother (a stay at home mom at the time and nurse was considering having another child) and was describing her dilemma to me when she told me this story of the problem that she was having with her son. So she tells the son that if the dog does not shape up, the dog will be gotten rid of. What about the boy's feelings about his mother. Was he thinking that if his mother could so easily get rid of the dog, would the mother then get rid of him. Clearly, The boy has a social problem particularly with his mother, perhaps with both parents as she may have framed her threat in "we terms." So I ask my students, how would you feel and what would you do if your parents threatened to take away someone you loved? What did he do to resolve the problem? Remember the boy was 4 year old at the time and mostly home with his mom. I would say that I have never had a student who conceived of such a creative solution to a problem as this boy had until I explain that the mom probably was describing her difficulty with the idea of having another child to her friends on the phone and the boy probably overheard her expressing her feelings.

What did the boy say to resolve the problem and in a way that re-established the moral order-- "that is my brother."

Well, she got her wish and amivalence resolved for her- a new addition to the family. Several years later I inquired as to the presence of the dog. He is still there.

Some of my students have similar stories, but not with the same ending.



Are oxytocin and testosterone always opposed to each other? Can you be high in both, and what sort of behavioral effects would happen then? I wonder, because I've always been known as a "nice guy", not a risk taker, happily monogamous for the last 30 years. But I've always had a strong libido, and I'm bald, which I always thought meant I had high testosterone.


Nice account and applaud you introducing the neurology of behavior beyond conscious choice, or socio-cultural factors. Of course, this feels very threatening to most folks. Especially guys it seems. Moral seems a good chice of words. Aside from rules and proscriptions, its defined by behavior.

But the physiology is what it is. More please.

Rudiger in Jersey

THere are many uneplored 'molecules' or drugs never tested or tested in specificl ways. What would a Viagra Nasal spray do to your ability to work CrossWord Puzzles...Science still hasn't given us an answer!

Alex C

Interesting article though I have a couple comments:

1) "While this may enhance health, it is an affront to personal liberty. If you like Coke, do you want "choice architects" in Washington saying you can't have them? "

Don't forget that being unhealthy imposes externalities on society, and impinges on my personal liberty for, say, reasonable health insurance costs.

2) I'm slightly disturbed by the possibility that we are over-diagnosing (and in a sense excusing) bad behavior. I.e. it's not Jose's fault he cheated on his wife he is just lacking in a certain hormone. We still need to hold people accountable for their actions, and I don't think focusing on a single hormone is the way to go. I think it's great that science is moving forward in this direction, I just hope that there is always a clear fine print that the brain is far too complex for one hormone to be responsible for such key area of human nature.


Christopher Strom

I noticed Zak makes a serious logical error when he proposes a slippery slope argument as being sound: "If you like Coke, do you want "choice architects" in Washington saying you can't have them? What's next, prohibiting hot dogs?"

Not only is this a misreading of Nudge - thank you, William #3 - but slippery slope arguments are logical fallacies that require a series of contingent (and generally unlikely) events to occur: A leads to B, B to C, etc, until A leads to Z.

Many commentors are make the same error by assuming that because one behavior tendency is associated with a particular hormone, then that hormone controls the behavior and therefore the individual is not responsible for his actions.

There are hundreds (at least!) of hormones that drive our behavior, of which we have identified only a fraction. For the smaller number of hormones we have studied in depth, we are beginning to uncover multiple effects for individual hormones, as well as interactive effects with others.

So while we may be able to say that depressed oxytocin and elevated testosterone encourage heedless risk-taking, we cannot say that Jose cheated on his wife only because his testosterone and oxytocin levels were wacky.


Linda Freedman, PhD

Yeah, but if Jose's dad also cheated, you know, there's this phenomenon called the notches on the belt :)

Nothing to do at all with thrills.


It is a well-known fact that Goldman Sachs sprayed a haze of oxytocin over the US.

Extinct Species

What Tony said (#12)

I must be way low on oxytocin. I never trust strangers, I have great trust in those who have earned it. Willing to take financial flyers from time to time but for the most part not much of a risk taker. Definitely not a thrill seeker. Libido - relatively strong, but never cheated on a partner while in a committed relationship. Why do these "scientific" revelations never seem to fit me?

Eric M. Jones

@16- Christopher Strom. Right on dude!

The power to tax is the power to destroy (thank god.). That is how we avoided the public health crisis of white phosphorus matches. The tax was raised to a buck-a-match. End of problem. This is what we call "civilization".

I too was surprised at the "slippery slope" argument. I would bet money that the Oxytocin testing is seriously flawed. These guys aren't scientists.

As for are true and committed to thier mates in inverse proportion to their available options. I suspect women too, but to a lesser degree. Remember the story about the pre-wedding detective agency that would set up fiancés in a bar with an attractive female "decoy" to see if they would cheat? The score was 30 cheating men to ZERO non-cheating men (before they ended the business...having caused apocalytic damage to local romances...).

I myself am seriously bothered by my Lamborghini Countach molecule. What will stop my cravings? A Murcielago and a testosterone injection simply won't do.