Mind Drugs


At least since the discovery of alcohol, humans have used drugs to affect the mind. As we learn more about how the mind works and become more skilled at chemical synthesis, we can expect to get better at it. In many ways this will be a good thing; already drugs provide substantial benefits to some sufferers from mental disorders. But, like most new technologies, improved mind drugs are also likely to raise new legal, social, and personal problems.

For the purposes of this chapter, it will be useful to consider four different classes of mind drugs: pleasure, performance, personality, control. Some drugs will fit into more than one category, reflecting multiple reasons why they are used.

Consider the familiar case of alcohol. Some people drink it because they like how it makes them feel – pleasure. Some drink it because they believe that it improves their performance; one acquaintance, as a college student, routinely had half a can of beer before an exam. Some drink it because it provides a temporary change in their personality that they sometimes desire. And some people feed alcohol to others, sometimes without their knowledge, as a crude way of controlling them.

Pleasure and Happiness

How might an everlasting-happiness drug – a drug which (implausibly!) left someone who tried it once living happily-ever-after – find itself described in the literature?

Substance x induces severe, irreversible structural damage to neurotransmitter subsystem y. Its sequelae include mood-congruent cognitive delusions, treatment-resistant euphoria, and toxic affective psychosis.


In most contexts we consider happiness and pleasure good things. Jeremy Bentham, one of the most influential philosophers of the nineteenth century, offered a simple standard for judging everything – its effect on utility, happiness, the excess of pleasure over pain in human life. Anything that increased utility was good; anything that decreased it bad.

Quite a lot of the chemical entities consumed by people in order to increase their utility are illegal. Supporters of laws against recreational drugs base their support on a variety of factual claims, some true, some false. It is not true that smoking marijuana makes people go crazy and commit violent crimes, as claimed in “Reefer Madness,” a movie that played an important role in inspiring the original anti-marijuana legislation. It is true that people on LSD are frequently incapable of performing ordinary tasks such as driving a car safely or conducting a coherent conversation. And it is true that some drugs have long-term adverse effects on some users.1

Whether or not the negative claims are true of some or all current recreational drugs, they are unlikely to be true of all future recreational drugs. The more we know about how the human mind functions, the better we will become at creating drugs that give pleasure without serious negative side effects.2 Unless, of course, it is pleasure itself that is the problem. Arguably it might be. Evolution is an extraordinary biochemist, much better than we are at producing compounds that affect living creatures in useful ways. If we can create a chemical that gives us pleasure, and if pleasure is a good thing, why don’t we come already equipped for pleasure on demand?

The obvious answer is that we are designed by evolution not for happiness but for reproductive success. Pleasure and pain provide incentives to act in ways that achieve that objective – to engage in sex, to remove our hands from hot stoves. Presumably there is some optimal balance, some normal level that allows enough deviation in one direction to give an adequate incentive to do things that serve the interests of our genes and enough in the other to get us to avoid things contrary to those interests.

If pleasure drugs are too good, they might interfere not merely with reproductive success but with physical survival. Larry Niven provides a fictional example3 in the form not of a drug but of direct electrical stimulation of the pleasure center of the brain. His “wireheads” are capable of plugging in and starving to death, because one more minute of intense pleasure is worth more to them than food or drink. If we accept this argument, the implication is not that pleasure drugs are bad but only that they should be used in moderation. It does not follow that they always will be.

For a less exotic example, consider a pleasure drug even more respectable than alcohol: the humble chocolate bar. If you have more elevated tastes, make it dinner at a four-star restaurant in Paris. Food, after all, is consumed largely to give us sensual pleasure. A minimum-cost, full-nutrition diet, based on flour, peanut butter, cabbage, and other high nutrition/low cost ingredients, comes to less than two dollars a day.4 The rest of what we spend is for pleasure.

The current real-world problem of trading short-term pleasure for more important long-term goals is, arguably, not the starvation of Niven’s wirehead but its opposite: obesity. People enjoy eating. Modern societies are rich enough so that almost everyone can afford to consume as many calories as he wants, an observation confirmed by half an hour spent people-watching in a low income neighborhood.5 One result is that a growing number of people, in the United States and elsewhere, are substantially overweight, heavy enough so that, on current evidence, they would live longer if they ate less.

A more general argument against pleasure drugs is that simple pleasure is not all that matters, as suggested not merely by philosophers but by observed behavior. Few couples have sex as frequently as would be physically possible; few single individuals masturbate as often as would be physically possible. If we imagine someone spending most of his life in a drug-induced haze, we may suspect that, however intense his pleasure, he is not really happy.

This suggests the least interesting response to the possibility of pleasure drugs – that they don’t work, that whatever their short-term benefits, in the long term they are a snare and a delusion. For all I know that may be true of the recreational drugs currently on the market, although I gather that many users of such disagree. But it is also largely irrelevant if we are considering the future.


Troy Dayton pops a little white pill every morning. He’s one of the 10 million Americans taking a daily antidepressant. But in his case, he says he was never depressed in the first place.

This 29-year-old political lobbyist is one of the happiest people you’ll ever meet. 6

Perhaps pleasure, in the sense provided by heroin and chocolate bars, is too narrow a goal. Since we are not limited to current technology, replace pleasure with happiness, the state of mind to which we think of pleasure as one input. Consider, not Niven’s wirehead, but the happiest person you happen to know.

My candidate is a fellow law professor who possesses what I like to describe as a glow-in-the-dark personality. Years after I got to know her, I happened to notice an old photograph in a law school display case showing a prominent professor receiving an award from the students. The central figure in the picture, the face that stood out from the rest, was not the recipient but the student giving the award. It was a face I knew.

It is possible, of course, that the happiness of such people reflects the fact that they have lots to be happy about: a loving spouse, children, a satisfying job, none of which can be provided by a drug. But that does not seem to be all that is going on. Studies of happiness suggest that happy people stay happy even when circumstances change, at least once they have had time to adjust to the changes. I was reminded of that result not long ago, attending a memorial event for a friend who had died a little less than a year earlier. His widow was there. It had been a happy marriage and a long one. But nobody who did not already know the facts, watching her, would have realized that she had recently lost the man she loved. She too, I think, is a naturally happy person.

So consider, not a pleasure drug, but a happiness drug, one designed to alter your brain chemistry in a way that will make you more like my glow-in-the-dark friend. If you could, would you? Should you? One possible answer is that such happiness is unnatural. Again the argument is that we have been designed by evolution, and evolution is much better at neurochemistry than we are. If brain chemistry that made us happy was a good thing, we would all already have it.7 The argument already offered for pleasure can be recycled for happiness. It too can be viewed as a reward programmed into us for behavior our genes approve of. It is harder to bribe rich people than poor people. Arguably, it is harder for our genes to bribe with happiness people who are already happy. While evolution may indeed be a very good biochemist, its objectives are not the same as ours. From the viewpoint of evolution, we are simply machinery by which genes make other genes. The design objective is reproductive success, the ability to increase the frequency of our genes in future generations.

That is not my design objective for me; if it were I would have more than three children. It does not seem to be the objective of many other people either; if it were, men would pay substantial sums to be permitted to donate to sperm banks and women who sold their eggs would do it at a negative rather than a positive price. Having someone else bear and bring up your children is, after all, an extraordinarily inexpensive way of spreading your genes.

Not only does evolution have the wrong objective, its designs are also out of date. Humans have long generations and so evolve slowly. Such evidence as we have suggests that we are adapted not to current circumstances but to the hunter-gatherer societies in which our species spent most of its existence.8 Even if too happy a personality is usually a liability in a hunter-gatherer society, and so rare, the same may not be true in a modern society. The happy people I know seem to do pretty well for themselves.

A second and more interesting objection is that utilitarianism is wrong, that happiness is not all that matters. To make that objection more plausible, consider two alternative lives I might live. One is the life I have lived. It has been, on the whole, a happy one. It has also produced a number of things I value – a happy marriage, three children, and half a dozen books, all of which I am proud of, a variety of ideas in several related fields, and many other things I am too modest (or lazy) to list.

The other is the life I might have lived if provided with suitable drugs, sufficient to make me at every moment of that life at least as happy as in the life I led. It is true that in that life I would not have had the pleasures of children, books, and other accomplishments. But I would have been compensated for that lack by an artificial increase in whatever brain chemicals connect the cause of accomplishment to the effect of happiness. Which life is more worth living? That is a question we will return to in a later chapter, in the context of virtual reality, another possible shortcut to happiness.

While it is an interesting question, it may not have much relevance to the effect of happiness – as opposed to pleasure – drugs. Judging by at least casual observation, whatever processes produce the natural equivalent of happiness drugs do not prevent their beneficiaries from living active and productive lives.

The CNN story on Troy Dayton’s use of Wellbutrin as a happiness drug contained a variety of dire warnings:

Psychiatrists tell CNN that Dayton’s use of Wellbutrin as a lifestyle drug is potentially dangerous, although little is known about the long-term effects. “These medicines are not harmless,” said Dr. Peter Kramer, author of Listening to Prozac. Kramer said some doctors think that if you stay on antidepressants long enough, you’ll come to rely on them. Other doctors believe they might trigger manic-depressive illness in susceptible people, he said.

The story offers no actual evidence of harm. The drug works by increasing the level of serotonin, a neurochemical associated with good feeling: “Chemically, there’s little difference between good feelings induced by medication and those occurring naturally.”


I would prefer my child take anabolic steroids and growth hormone than play rugby. Growth hormone is safer than rugby. At least I don’t know of any cases of quadriplegia caused by growth hormone.

Julian Savulescu, professor of practical ethics at Oxford9

The performance drugs that are currently a public issue deal with the body, but they raise many of the same issues as drugs to improve mental performance. Everyone seems to agree that it is a bad thing for athletes to use steroids, but it is not entirely clear why. Athletes have, after all, been using diet and exercise to improve their performance for thousands of years, as well as a variety of older drugs. Why does the process suddenly become sinful when they switch to steroids?

One answer is that since steroid use is presently prohibited, those who use steroids are getting an unfair advantage. But that does not explain why they are presently prohibited when other ways of getting an advantage are not. A second answer is that we are afraid young athletes, with inadequate concern for their own future, will do themselves serious damage in the process of trying to win. But while taking steroids may reduce life expectancy – the evidence seems to be a good deal weaker than popular discussions suggest10 – so does driving a car around a racetrack at something over 200 miles an hour, which young race car drivers are permitted to do. Why is our paternalism so selective?11

The most interesting answer, at least to an economist, is that our opposition comes from the special nature of the product that athletic contests produce. Arguably, most of what we care about is the relative, not absolute, ability of the athletes. A footrace in which one competitor manages a mile in 4 minutes and the other in 3 minutes and 59 seconds is just as exciting as one where the times are 3:59 and 3:58. We want our favorite baseball team to play a little better than its opponents but care little about the absolute level at which both play. To the extent that this claim is true – some sports fans would dispute it – competition via steroid use is a mistake. Both teams, boxers, or runners get a little better, their relative ability is unaffected, the fans are no happier and the athletes die a little younger.

Consider next the mental equivalent of steroids. Ritalin, for example, is usually thought of as medication for Attention Deficit Disorder (ADD). It turns out, however, that one cannot tell if someone has ADD by giving him Ritalin and seeing if his concentration improves, because Ritalin improves everyone’s concentration. It follows that someone who wants to do well on, say, a bar exam, might be well advised to somehow obtain some Ritalin to take before going into the exam – and I gather some people do. Other illegally obtained drugs, such as speed (amphetamines), are reported to be in common use for similar purposes. Perhaps when the due date for a paper approaches, a student given to procrastination might want to obtain some modafinil,12 a drug that appears to eliminate the need for sleep for substantial periods of time and is, if news stories are to be believed, currently used for that purpose by the U.S. military.

One argument for prohibiting the use of such drugs by those taking the bar exam, or SATs, or a final, is that they distort the information that the exam produces. A law firm deciding whether to hire you doesn’t want to know how good a lawyer you are when you are under the influence of Ritalin unless they expect you to continue to consume it regularly for the rest of your working life. They want to know how good a lawyer you are under the conditions under which you will be working.

That makes sense as long as we are only talking about temporary effects. The question becomes more interesting if we consider a drug that can be used on a regular basis – as people diagnosed with ADD in fact use Ritalin – or one that produces long-term rather than short-term effects. We then have the mental equivalent of a steroid.

Some of the hostility to the regular use of such drugs, as for steroids, is based on the idea that all they are doing is helping the user win a competition, not on the playing field but in the job market. If both competitors use the drug neither gains any relative advantage and both are worse off by whatever the costs of the drug, in money or health, happen to be.

That argument reflects a fundamental misunderstanding of economic competition. If you and I are runners and both use steroids, both run a little faster and you still win the race. Nothing is gained and, if steroids have undesirable side effects, something is lost. But if you and I are house carpenters who use an improved version of modafinil to increase both labor and leisure, working ten hours out of twenty-two instead of eight out of sixteen, the result is that more houses get built. The ultimate benefit might go to us as more income from our greater productivity and more leisure to enjoy it in. It might go to people who buy houses, if our increased output drives down the price of our services. It might be divided between us and our customers. The details of what happens depend on the details of the market for our services. But in all of the outcomes, the extra time that we have gotten by drastically reducing our need for sleep, or the superior quality from improving our ability to pay attention, is producing a real benefit for someone, not merely a competitive advantage.

The argument applies wherever absolute and not merely relative results matter, which means almost everywhere. “Competition” is a misleading term because it suggests that, as in athletic contests, all that matters is who wins. Farms do not exist to win a competition but to produce food. Carpenters do not exist to win a competition but to build houses and chairs and tables. Drugs that make us more alert, or smarter, or give us better memories, or reduce the need for sleep, let us do whatever we are doing better. That is a net benefit to be balanced against any costs associated with use of the drug.

Do drugs give us better memories? That is still an open question, one closely associated with the attempt to reduce memory loss due to Parkinson’s disease. But there is good reason to believe that such drugs will exist, and at least some reason to believe that we already know of drugs that to some degree improve memory.13 The same claim is sometimes made with regard to intelligence – that there now exist “smart drugs.” Whether or not they do exist, it seems likely that they will.

It may occur to some readers that the argument I have offered to explain concerns about enhancement drugs, however entertaining to an economist, is too clever by half, that most ordinary people do not distinguish between activities that are purely competitive and those that are productive. An alternative explanation, and one that provides at least a partial explanation of hostility to many different technologies, is that people are simply conservative, skeptical of anything new, “unnatural,” despite the unnatural nature of virtually everything we currently eat, drink, or wear.

As evidence, I offer the following comment on modafinil from a doctor who deals with sleep disorders: “I think sleep is a good thing. The healthy thing to do is to sleep more if you’re tired, right?”

A conjecture converted into a fact under your very eyes.


Earlier in this chapter I raised the question of whether the opportunity for pleasure might make us worse off rather than better off. One example is obesity. I weigh more than I believe I should, yet have a hard time losing weight. Like many other people, I can resist anything but temptation. As we develop ways of easily obtaining much more intense pleasures, there is some risk that we may be tempted into giving up long-term benefits in exchange for short-term benefits even when we should not. This raises an obvious question: What does “should not” mean? How, other than by observing the choices people make, can we judge their values? What do I mean if I say that I did one thing but should have – in some sense really wanted to – do another?

An approach to that question that I find intuitively appealing is to think of myself as two people in one, a long-term planner and a short-term current utility maximizer. The planner uses devices such as guilt and commitments to try to manipulate the short-term maximizer, the me in actual control of my body. I might decide – have from time to time decided – that I will not permit myself to have ice cream for dessert until I have gotten my weight below some arbitrary level. I might decide – in fact decided, not long before typing these words – to set a lower limit to my day’s written output, a number of words I must produce before permitting myself to go to bed or indulge in World of Warcraft. Sometimes the devices rely on external aid, as when an employee arranges to have a certain amount of his income automatically transferred each month to a savings account.

This way of looking at it suggests an intriguing possibility. Perhaps the problem with pleasure drugs can be dealt with by personality drugs. Some people appear to have a longer time horizon than others, to be more able to control their desire for immediate pleasure in order to better achieve their long-term goals. Perhaps, as we learn more about how the brain works, we will discover that the difference reflects some difference in brain chemistry. Perhaps personality drugs will finally put the long-term planner in the driver’s seat.

Consider, for example, what we already know about the effects of dopamine, a neurotransmitter that plays an important role in brain chemistry. A shortage of dopamine in the brain results in an indecisive personality; Parkinson’s disease is an extreme version. Mice with excess brain dopamine, on the other hand, are highly exploratory and adventurous.14 We do not yet know in any detail the mechanisms that produce these results, but they at least demonstrate that personality depends in part on brain chemistry.

For a more striking example due to a more drastic alteration of the brain, consider the most famous anecdote in the field: the sad history of Phineas P. Gage. As a result of a moment’s carelessness with explosives in 1848, he succeeded in driving a four-foot metal rod entirely through his head, leaving a hole in his brain case into which the attending physician was able to insert his entire index finger. Surprisingly enough, he recovered from the injury in a few weeks and returned to his job as foreman of a railroad blasting crew. “He had no apparent intellectual deficits or memory losses. Yet, his return to work quickly showed the nature of the deficit that follows massive frontal lobe damage. The formerly mild mannered, thoughtful, and cooperative foreman had been transformed into a cursing, belligerent tyrant. He lost his job, joined a traveling sideshow for a few years to capitalize (in a small way) on his misfortune, and died of an epilepsy attack about 13 years later.”15

Whether or not personality drugs can be used to give us better than average personalities, they are currently being used to deal with personalities seen, by their possessors and others, as worse than average. Bipolar disorder is one example, depression another. Both can be seen as personality disorders. Both are treated with drugs, in at least some cases with apparent success.


Candy is dandy but liquor is quicker.

So far we have been considering things we might be able to do to ourselves, using drugs. There remains the issue of things other people might do to us. Two obvious examples are drugs to make the victim unconscious – chloral hydrate, the “Mickey Finn” of old detective stories, and its more modern equivalents – and the use of alcohol as an aid to seduction. Newer drugs might serve the same purpose. One effect of ecstasy (MDMA) is to make the user warmer, more empathetic. Under most circumstances that is a desired effect, an example of the use of a drug to change one’s personality. But it is also a reason why a man might feed the drug to a woman he was trying to seduce.

As this example suggests, the difference between personality drugs and control drugs depends not so much on the nature of the drug as on how it is used. A woman who gets herself drunk in order to let herself be seduced is using alcohol to temporarily alter her personality. A man who gets a woman drunk for the same purpose is using it to control her.

The present range of control drugs is pretty limited. There are knockout drugs. There are drugs that induce temporary amnesia, such as Rohypnol, sometimes called the date rape drug. There are drugs such as alcohol and marijuana that relax people and make it harder to think clearly. That’s about it.

There is, however, evidence of more on the horizon. One odd set of experiments involving the reaction of some people to smelling other people’s perspiration suggest that there may be human pheromones, compounds that make someone smell sexy to someone else; perhaps some perfume actually works.16 If we can isolate such compounds and figure out how they work, we may be able to produce the same effects in a much more powerful form. Aphrodisiacs may today be mostly mythical, but there is always tomorrow.

Still more disturbing is the possibility of drugs that make the consumer credulous, willing to believe whatever he is told, or obedient, or loyal. There is some evidence that oxytocin has such an effect.17

To get some feeling for how a loyalty drug might work, consider the Mule, a character in Isaac Asimov’s Foundation trilogy, an old and famous work of science fiction. The Mule had one simple talent: the ability to make people want to serve him. He used it to build an interstellar empire. His servants knew perfectly well that they were loyal because he had used his special ability to make them so, but it didn’t bother them. Serving the Mule was the best thing they could possibly do, so why should they resent the fact that he had made them want to do it?

That is only science fiction, but there is a real-world equivalent that all of us have observed and many experienced: the feeling of parents toward their children. Parents love their children and wish to serve and protect them, not because the parent has made an objective judgment about how deserving their children are but because the parent has been programmed by his genes to feel that way, by mechanisms some of which may well be chemical. Parents who happen to be evolutionary biologists know that their children have them by the genes and why; they still feel the same way.

We are descended from people who not only produced children but took sufficiently good care of them so that they in turn reached maturity and reproduced; we have been selected, over a period longer than our species has existed, for the characteristic of altruism toward our own children. But that evolutionary explanation tells us nothing about the underlying mechanism, just as the observation that being able to see makes it much easier to survive tells us nothing about how the eye works. If we could learn to understand the mechanism, the nature of the internal changes that support parental love, we might be able to use that knowledge to make others love us as if we were their children. Similarly for romantic love, which produces effects in some ways very similar.

We are only just approaching the ability to do this sort of thing, but we have been thinking about it for a long time. Consider Ariosto’s Orlando Furioso, a sixteenth-century work of fantasy fiction whose characters spend their time wandering about a vast forest that seems to stretch roughly from England to China, geography not being one of Ariosto’s concerns.

The forest is well provided with pools and springs for the use of thirsty adventurers. As best I can make out – I read the book quite a long time ago – there are three different kinds. Drinking from the first eliminates your memory. Drinking from the second makes you hate whatever being you most loved. Drinking at the third makes you fall in love with the next living thing you see. For Ariosto they were only a convenient plot device, a way of getting his characters into amusing and entertaining situations. We already have versions of the first spring – Rohypnol, for instance, although its effect is briefer. The rest may be coming.

Suppose we develop much better control drugs; how might our laws and institutions adjust? One possibility is a legal regime under which a contract is binding only if both parties have been tested just before they signed to make sure neither was under an influence that would make him unreasonably credulous or suggestible. If there are reliable seduction drugs that can be given to a potential victim without consent, perhaps we should ban all sex not preceded by suitable drug tests. Critics of current campaigns to define date rape as broadly as possible might argue that we are already most of the way there.

Not all forms of protection depend on changes in the law. The simplest protection against being drugged is not to drink from a glass or a container that someone else has had an opportunity to slip something into. Carrying self-protection a little further, there currently exist simple chemical tests for the presence of date rape drugs. Unobtrusively dribble a few drops of your drink onto the test strip; if it changes color, remember that you have urgent business elsewhere.18 One can imagine more sophisticated versions, as defensive technology improves to match improved offensive technology. Perhaps we will eventually use nanotechnology to equip ourselves with microscopic chemical labs that continually monitor our bloodstreams and let us know if there is anything there that shouldn’t be.

Conditions of Employment

So far in the discussion of control drugs I have been assuming that they are given to people without their consent. There is another way they might be used that moves us to the borderland between drugs that I use to change my personality and drugs that you use to control me.

There are quite a lot of jobs for which loyalty is an important qualification. Suppose I am hiring for a firm whose employees will have profitable opportunities to benefit themselves at the firm’s expense, to pocket small and valuable items or sell the firm’s trade secrets to its competitors. After calculating the cost of watching everyone all the time, I decide to offer two different employment contracts, one paying $50,000 a year, one $100,000. There is only one difference between the two contracts: The second one requires the employee to consume a drug that makes him loyal to the firm.

One might object that letting someone agree to such a contract is rather like letting him sell himself into slavery. One might respond that to forbid the contract means to deny the individual control over his own body and mind. And one might also note that what I have described is merely a new technology for an old purpose. Firms, armies, and nations have been using more primitive methods to try to make people feel loyal for a long time.

The contractual loyalty drug does, however, raise some interesting issues. Once you have taken the drug, what is to keep your employer from suggesting that you voluntarily return to him half your salary and what keeps you from loyally agreeing to do so? Perhaps the contract should include some special safeguards.

An important question here is whether the drug makes you permanently loyal, as parents are permanently loyal to their children, even to children that only a mother could love, or whether the loyalty wears off with the drug. In the latter case the employer may have to rely on your loyalty to make you take the next dose – and a loyal employee may still be absent-minded. It might be more prudent to institute mandatory drug testing intended to make sure not that you are not on drugs but that you are.

The Chemistry of Love

The feelings of euphoria, sleeplessness, and loss of appetite, as well as the lover’s intense energy, focused attention, driving motivation, and goal-oriented behaviors, his/her tendency to regard the beloved as novel and unique, and the lover’s increased passion in the face of adversity might all be caused, in part, by heightened levels of dopamine and/or norepinephrine in the brain. And the lover’s obsessive cogitation about the beloved might be due to decreased brain levels of some type of serotonin.

Helen Fisher, Why We Love

The pattern of behavior we associate with falling in love is shared by many other species, a fact that greatly simplifies the investigation of its causes and nature; it is easier to get approval for experiments on rats than for experiments on people. The resulting research on the relation between romantic love and brain chemistry provides possible examples of all the sorts of mind drugs I have been discussing.

Falling in love is for some people an intensely pleasurable, indeed addictive, experience, which may explain why some men fall intensely in love with one woman and then, after their efforts meet with success, lose interest and fall in love with another. A famous example is Giacomo Casanova, the historical figure whose name has become a synonym for male inconstancy. Judging by his memoirs, he was a much nicer person than the modern usage of his name suggests; he seems to have taken considerable efforts to assure the future well-being of his ex-lovers, and some remained friends and correspondents for decades after the end of the affair. But he did fall in love with a very considerable number of women and the intensity of his passion predictably cooled over a period of perhaps a month or two after its success.

Arguably, the difference between Casanova and the rest of us is only a matter of degree, not of kind. I love my wife very much but I am not in love with her in the sense in which I was when I first courted her some thirty years ago. Not only are the two emotions different subjectively, there is some evidence that they are related to different neurochemicals in the brain. My feelings when I was first in love with her in some ways are more like my feelings for our children, especially when they were young, than they are like my current feelings for her. Parental love features the same intense focus, the same feeling that one being is the most important thing in the world, as romantic love. I suspect, but do not know, that with sufficient research one would find that some of the same neurochemicals are involved in both.

Recent research on the nature of love, focused on the connection between behavior and brain chemistry, distinguishes three different but related behaviors: falling in love, attachment, and lust.19

Falling in love is a behavior pattern familiar from literature, movies, television and, for most of us, firsthand experience. A central symptom is the wholly irrational belief that one person is the most important thing in the universe, the proper target for most of one’s thoughts, hopes, and attention. It is not a pattern limited to humans; a wide range of animals, from elephants to rats, appear to fall in love as well. In animals as in humans, the behavior is closely linked to mating behavior.

Humans rarely stay in love; typically, the feelings and associated behavior last for months, not years. Sometimes love is succeeded by attachment, a behavior pattern associated with less intense emotions and one that can, with luck, last a lifetime. We do not fully understand the mechanisms underlying these patterns of behavior, but it seems clear that they are associated with known neurochemicals and known areas of the brain. Suppose, as seems likely enough, that further research makes it possible to control them, to fall in and out of love, to maintain or destroy the emotions of romantic attachment, to turn love and lust on or off, with a pill, a patch, an injection. What consequences would follow?20

The consequences of involuntary use are obvious and unattractive: a pill that makes a beautiful woman fall in love or, for shorter-term objectives, lust, with you. What about voluntary use?

Many years ago I spent a long airplane flight – from Bombay to Sydney – next to a woman from southern India, flying out to join her husband. She came from a society where arranged marriages were taken for granted. Her husband had been selected for her by her parents, although she had then met him before consenting to the arrangement. I came from a society where it was taken for granted that individuals found and selected their own mates. She accepted her society’s arrangements and was intrigued by the odd way we did things; I felt much the same in the other direction. And she was, not a stick figure in a history or anthropology text, but a living, breathing human being, obviously intelligent and thoughtful. Furthermore, on at least our small sample, the superiority of the Western system was far from clear; she was happily married, I recently divorced.

It was a very interesting conversation and I came away from it less certain of the superiority of our system. Choice of a mate is, after all, a difficult and important decision, and it is hard to imagine anything further from a coldly rational being than a man in love. On the other hand, being in love is not only an intense and moving experience, it is also a natural and appropriate preliminary to a lifetime of attachment, at least arguably designed by evolution for the purpose.

Perhaps in the brave new world of modern chemistry one will be able to get the best of both worlds. First I select a spouse by some suitably calm and objective analysis, making use of the services of a professional matchmaker to find a woman ideally suited to be my wife – one requirement being, of course, that I am ideally suited to be her husband. After she and I have agreed on the match, either just before or just after the wedding, we take our pills, look into each other’s eyes, and fall deeply and passionately in love. After six months or so of ecstatic but distracting bliss – both of our employers are beginning to worry about declining job performance – we switch the prescription from passion to attachment and so shift into a long and satisfying marriage. If on some suitable future occasion, say a tenth anniversary, we feel in need of a second honeymoon, perhaps there are still a few pills left over from the first prescription.

It sounds like science fiction, but it is not entirely clear that it is not also very old, if only occasional, fact. I am not certain if my Indian friend was, or had been, in love with her husband, but she certainly appeared attached to him. It is entirely possible that arranged marriage might sometimes have led to romance, especially in a society where young adults were segregated by sex, so that your wife might be the first suitable young woman you had an opportunity to fall in love with.

Not only may the love be an old story, but the chemistry as well. Sex, as many of us have observed, has emotional concomitants. Also chemical. “At orgasm, levels of vasopressin dramatically increase in men and levels of oxytocin in women.”21 The connections between those hormones and the neurotransmitters that seem to be associated with romantic love – dopamine, norepinephrine, and serotonin – are complicated but clearly exist.22 It is entirely possible that the pills I have described are already engineered into us, in at least a weak form.

Which brings us back to one of the central conflicts of our culture: the case for and against nature. We routinely use “natural” as a term of praise: natural food, unspoiled nature, natural childbirth. And yet we have constructed our world in large part to avoid the defects of nature. Unnatural childbirth, up to and including caesarean section (currently more than one-quarter of all U.S. births), is the reason that death in childbirth is now a rare tragedy instead of a common occurrence. Very few residents of either Chicago or Houston prefer, given the choice, to maintain their houses year-round at their natural temperature. And very nearly all of the plant foods we eat – almost all grains, fruits, and vegetables – are unnatural, the result of many generations of selective breeding from natural plants that few of us would think worth eating.

If not our houses, what about our hearts? Nature or art? Are we better off being led into and out of love, into and out of occupied beds, into and out of marriage by the natural processes engineered into our minds and bodies or are we better off deciding when and whom to love by means of our reason, assisted where appropriate by expert advice, and then implementing our decisions through the marvels of modern chemistry?

And, to descend for a moment from high flown speculations, in that future will “He refused to take his attachment pill” be legitimate grounds for divorce? Will recreational sex morph into recreational love? Will singles bars offer two extra-special drinks, one with a falling-in-love drug, to take before heading out to his place or yours, and one with the antidote?


Some readers, following my endnotes, may have noticed repeated references to works by Matt Ridley dealing not with drugs but with genetics. That is not an accident. The chemical mechanisms that generate our natural mind drugs are under genetic control. The study of how genes affect behavior is intimately connected with the study of how chemicals in our brain affect behavior. Studying mind drugs by injecting chemicals into people’s brains and seeing how they react raises serious practical and ethical difficulties. An attractive alternative is to observe people who, possibly for genetic reasons, behave in different ways and checking their blood to see what is in it.

There is a second link between the two studies. Drugs may provide a temporary way of doing what genes do for good. If it turns out that increasing the level of serotonin in the brain makes people happier, a tempting short-run approach might be to feed people, or inject them, with something that results in increasing serotonin levels. If that turns out to work, a longer run approach might be genetic manipulation to increase the level that we produce. Perhaps we could even identify a “happiness gene,” some gene or group of genes that are common in strikingly happy people, and find some way of artificially increasing its frequency in the population. Perhaps the next time I happen to run across my glow-in-the-dark friend I should ask her for a blood sample to pass on to some ambitious researcher.

You too can have happy babies.


1 For reasonably objective information on drugs, see Rosen and Weil, 2004, and the Erowid web page, http://www.erowid.org/.

2 For instance, non-addictive recreational drugs. Consider also the possibility of anti-addiction vaccines.

3 Wireheads appear in a number of Niven stories, including “Death by Ecstasy” in Niven, 1969.

4 The original calculations, long out of date, were in Stigler, 1945. A current version, for 1998 prices and RDA, is described in Gass and Garille, 2001. “The updated problem shows that the optimal solution diet for a 25–50 year old man consists, on a daily basis, of 1.31 cups of wheat flour, 1.32 cups of rolled oats, 16 fluid ounces of milk, 3.86 tablespoons of peanut butter, 7.28 tablespoons of lard, 0.0108 ounces of beef liver, 1.77 bananas, 0.0824 of an orange, 0.707 cup of shredded cabbage, 0.314 of a carrot, 0.387 of a potato, and 0.53 cup of pork and beans. The daily cost of this diet is $1.78.”

5 The more rigorous statistical equivalent finds obesity more common in lower income Americans, but not by much.

6  CNN, November 17, 2006 .

7 It may occur to some readers to wonder why, if being by nature very happy is a liability, there are any very happy people; why does my glow-in-the-dark friend exist? From the standpoint of evolutionary theory, the answer is that how successful a particular human design is depends in part on how common it is. What we would expect, and what we observe in many areas, is not a single design for every human but a range. Tall people are better at, among other things, picking high growing fruit. If there are few tall people there will be a lot of unpicked fruit high up, making height an advantage. If there are lots of tall people that advantage is no longer available to balance the disadvantages of height. Similarly for personality. If almost everyone is cautious, there will be attractive opportunities to be grabbed by the few who are brave. I will leave it to the reader to work out the advantages to being naturally happy in a world where everyone else is naturally glum.

8 Although there is now some evidence suggesting evolutionary changes in humans within the past ten thousand years.

9 The source of the quote and an article by Savulescu et. al.

10 For a fairly detailed discussion, see Mehlman, Benger, and Wright, 2005.

11 Another answer that has been offered is that present athletes are competing against past athletes, trying to break their records. The past athletes did not have access to steroids, so steroid use by present athletes is unfair competition. Past athletes also did not have sports equipment reinforced by carbon fibers, modern training, and diet regimens, and a variety of other things that present athletes have – but perhaps this is the one advantage we hope to be able to control.

12U.S. military studies found that soldiers can stay awake and function alertly for 40 hours, get 8 hours of sleep, and then stay awake for 40 more, all without the impaired judgment of old-fashioned uppers.There is also evidence that the drug boosts mental abilities in other ways.

13 There is, for instance, evidence that Donepezil improves learning; subjects who learned under the drug were more likely to remember what they had learned later.

14 Ridley, 1999, p. 162.

15 From C. Robin Timmons and Leonard W. Hamilton, Drugs, Brains, and Behavior, largely based on Timmons and Hamilton, 1990.

16 Spencer, McClintock, Sellergren, Bullivant, Jacob, and Mennella, JA, 2004. See also http://pheromones.com/professional.html.

17 Evidence of the effect of Oxytocin on willingness to trust. There is also evidence linking Oxytocin to mating behavior in both males and females, including the tendency to monogamy. Two different species of moles, one monogamous, one not, differ strikingly in the distribution of Oxytocin receptors in their brains. The symptoms of monogamous behavior can be created in the non-monagomous species by injecting Oxytocin (or Vasopressin) into their brains, or repressed in the monogamous species by injecting chemicals that block the Oxytocin receptors. The results are reported in Ridley 2004.

18 “Drink Safe Technology” is a package of testing strips for date rape drugs.

19 Fisher, 2004, especially chapter 4.

20 I am not the only one to have thought of the idea; for a brief sketch see "The Modern Makeover."

Also the discussion by Nick Bostrom in secton 6 of his "AHistory of Transhumanist Thought."

21 Fisher, 2004, p. 89.

22 Fisher, 2004, pp. 89–92.