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Neuroethics 101

A Primer on Emerging Neurotechnologies, and How Society Must Deal with Them


Neuroethics is a relatively new field within bioethics, concerned with the ethical, legal, and social impact of neuroscience. It emerged in response to the rapid development of neuroscience in the late 20th century, including our understanding of human cognition and emotion, along with functional neuroimaging, which became widely available in the 1990s.

As a result of the maturation of cognitive and affective neuroscience, neuroscience can now be brought to bear on solving problems in many spheres of human life beyond clinical medicine. Any field that requires understanding, assessing, predicting, controlling, or improving human behavior will find neuroscience relevant. This includes the spheres of education, business, politics, law, entertainment, and warfare.[1]

With the growing applicability of neuroscience comes a growing set of ethical issues concerning its use. In order to explain the nature and scope of neuroethics, it is necessary first to review the most ethically significant new uses of neuroscience. We therefore begin with examples of how neuroscience is being used in all of these areas, and then present an analysis of the ethical issues raised by these applications.

New roles for neuroscience in society


The emotions and motivations of consumers are a particularly important focus for marketers, so the prospect of “reading” the brain-states of consumers is therefore of great interest. Compared to some psychological states, those of liking and wanting have a relatively straightforward relation to patterns of brain activity. Electroencephalography, or EEG, and functional magnetic resonance imaging, or fMRI, two advanced techniques for measuring brain activity, have therefore become widely used tools in market research, and in 2002 the term neuromarketing was coined to refer to this research.[2]

Published research in the field of neuromarketing is more focused on academic issues—such as the nature of the brain activity underlying consumer behavior and the accuracy of brain-behavior predictions—than on the real-world utility of neuromarketing for improving business. From published research we have learned the ways in which packaging design, price, brand identity, spokesman celebrity, and other marketing factors separate from the product itself affect neural responses to the product—how accurately those neural responses predict purchasing decisions.[3][4] Although the information gleaned in such studies is, in principle, obtainable through more traditional behavioral methods of marketing research, in many cases brain imaging appears to provide more sensitive measures of consumer motivations.

The success of neuromarketing as a business tool is harder to assess, but the list of companies paying for neuromarketing services suggests that many corporate decision makers have faith in it. Forbes magazine reported that this list includes Chevron, Disney, eBay, Google, Hyundai, Microsoft, PepsiCo, and Yahoo.[5] The techniques of neuromarketing can also be used to study preferences for health behaviors[6] and political candidates.[7]

Criminal justice and the law

Neuroscience is potentially applicable to all of the same areas of criminal justice and the law to which psychology has already been applied.[8] Within the criminal justice system, this includes a variety of sentencing options referred to as “therapeutic justice,” where offenders are sent for anger management classes, parenting classes, treatment for drug dependence, and a variety of other forms of behaviorally-based psychotherapy.

In many states within the United States, one particular form of brain-based therapeutic justice is already being practiced: Sex offenders may be given long-acting forms of anti-androgen medications, which reduce sexual desire. This so-called chemical castration is effective because of how it affects the brain. Other psychopharmacologic treatments with potential for therapeutic justice include serotonergic drugs such as selective serotonin reuptake inhibitors, or SSRIs, which have been found to be effective for reducing repeat offenses in sex offenders, as well as reducing impulsive violence.[9][10]

Defendants’ personal, medical, and psychological history and diagnoses have long been introduced in court as mitigating factors at the sentencing phase of criminal trials. Information about defendants’ brain function has also increasingly been introduced.[11] In principle, neuroscience can also play a role in assessing dangerousness and risk of recidivism. Such information—to date based on behavioral history and psychological examination—is used in sentencing and parole decisions. Brain imaging studies of murderers have distinguished between impulsive murders and those who planned their crimes, the latter being more likely to murder again.[12]

Other possible legal applications of neuroscience extend beyond the criminal law to such general considerations as jury selection and the evaluation of testimony. In connection with jury selection, lawyers and the courts seek to eliminate jurors with biases that could impair their ability to deliberate in an open-minded way. This task is challenging because jurors may not report or even be aware of their biases. Functional magnetic resonance imaging has been shown to assess certain types of unconscious bias in cooperative subjects.[13][14]

fMRI has also been used to measure the likely truthfulness of statements,[15][16] although to date such methods have not been admitted as evidence in a court of law.[17] A different type of brain-based lie detection based on event-related potentials has been admitted as evidence in the United States (Harrington v State of Iowa) and in India. Indeed, in India the method has helped convict at least two defendants of murder.[18]

‘Lifestyle’ brain enhancement

For millennia people have been improving their alertness and mood with naturally occurring substances such as nicotine and alcohol. With the advent of modern psychopharmacology and other methods of altering brain functions, the options for nonmedical brain enhancement have expanded.

Medications intended for the treatment of attention deficit hyperactivity disorder, or ADHD, are now commonly used by healthy college students as study aids.[19] The results of a 2001 survey of more than 10,000 American undergraduates showed that 7 percent had used a prescription stimulant nonmedically, and this figure ranged as high as 20 percent on some campuses.[20]

Anecdotal evidence, along with a variety of informal journalist’s surveys, suggests that many students and professionals have added a range of other psychopharmaceuticals, beyond the conventional ADHD medications to their work routines.[21],[22],[23],[24],[25] The most popular of these appears to be the drug modafinil, initially developed to reduce sleepiness in narcoleptic patients, but which also counteracts many of the cognitive symptoms of sleep deprivation in healthy normal users. This allows for more comfortable and productive “all-nighters.”[26],[27],[28],[29]

Some research suggests that modafinil may also enhance aspects of cognition in healthy people who are not sleep deprived.[30] The ability to control when one gets sleepy—and perhaps even “work smarter,” as well as work longer—has obvious lifestyle allure. Although healthy people comprise some of the market for this drug, it is not known how much of the market they comprise. It is presumably limited by the expense of the drug, the need for a prescription, and, last but not least, the unknown long-term effects of cheating one’s body of sleep in this way.

Looking a bit further out on the horizon into the coming decades of the early 21st century, there are likely to be a number of new cognitive enhancers available.[31] Drugs to suppress unwanted memories are also the object of research and development.[32]

Pharmaceutical approaches to cognitive enhancement have recently been joined by other technologies, including transcranial brain stimulation by magnetic fields (transcranial magnetic stimulation) or electric currents (transcranial direct current stimulation). At present these technologies are the focus of active research programs on the manipulation of normal and abnormal brain function.[33] In particular transcranial direct current stimulation has earned the attention of researchers in recent years for its ability to enhance a variety of cognitive processes in healthy research subjects using inexpensive and portable equipment.

Security applications: Intelligence and military

National security concerns have driven the development of many technologies, including neurotechnologies.[34] Much of the success of both intelligence and military operations depends on personnel—specifically on their psychological strength and dependability, which are both functions of the brain.

Of course, information about security applications of neuroscience is often not accessible to the public. On the basis of available information, it has been surmised that brain imaging is likely to be among the methods being studied or used for interrogation.[35] Recent research in cognitive and social neuroscience on mechanisms of deception, inhibitory control, and trust has obvious relevance to the development of methods to weaken an interrogatee’s ability to withhold information.[36]

Personnel selection is critical for both intelligence and military operations, where loyalty and psychological resilience may be challenged under extreme conditions. Despite its many shortcomings, the polygraph has a long history of use in security screening. Might advanced brain imaging systems, like ERP or fMRI, as imperfect as they are, be used for lie detection instead of or in addition to the polygraph to provide a degree of evidence on truthfulness? Might brain imaging markers of vulnerability to anxiety or other disorders have a place in screening personnel for the stress of combat?

In addition to assessing or predicting the psychological traits of personnel, there is a strong military interest in enhancing personnel.[37] It is well-established that war-fighting personnel use a variety of psychopharmacologic agents to increase concentration, decrease fatigue, and counteract anxiety.

Amphetamine has a long history in the military,[38] joined more recently by modafinil,[39] and SSRI use is reported to be common among American troops in Iraq and Afghanistan.[40] Other enhancements under development by the military are quite different from those shared with the civilian world. One example is the U.S. Defense Advanced Research Projects Agency project known as “Luke’s binoculars”.[41] The device measures electric signals coming from the brain to alert the wearer to his or her own unconscious perception of a relevant stimulus or event. This enhancement of visual attention is projected to be in use within a few years.

Another example is a portable transcranial magnetic stimulation, or TMS, device for delivering brain stimulation in the field.[42][43] A final area of military applications of neuroscience consists of the development of nonlethal weapons.[44][45] Methods that render the enemy temporarily sleepy, confused, in pain, or terrified would all have their effects by selectively influencing brain function.

In sum, the early 21st century has seen a proliferation of new applications of neuroscience. Pharmacologic manipulation of brain function for lifestyle reasons is already commonplace on campuses and in some workplaces. A number of new drugs and nondrug methods for enhancing everything from cognition to libido are on the market or in development. Brain imaging has been commercialized for applications ranging from lie detection to the assessment of romantic compatibility, and all of these methods for monitoring and manipulating the brain have found their way into government uses, from criminal justice to warfare.

Ethical issues of emerging neurotechnologies

Brain privacy

The uses of brain imaging reviewed here raise a number of ethical and legal issues related to privacy. Bioethicists have discussed many of these issues in connection with genotyping, or the analysis of an individual’s genetic makeup.

Brain imaging and genotyping are similar in that both involve measures that can be taken for one stated purpose and used for a different one, either contemporaneously or later. The brain, however, is a causal step closer than genes to the behavioral endpoints of interest and may therefore ultimately be more psychologically revealing.[46],[47] In addition, unlike genes, which can be informative about enduring traits only, brain imaging can deliver information about psychological states, including the states of preferring a certain political candidate or intentionally deceiving someone.

We suggest that brain imaging will raise substantial challenges to privacy but these challenges will not be qualitatively different from others in genetics, psychology, and information technology. As the brief reviews of neuromarketing and brain-based lie-detection indicate, these technologies deliver fairly specific types of information, as opposed to being general-purpose “mind readers,” and both require a cooperative subject. They may deliver information more directly than traditional behavioral methods, but it has yet to be demonstrated that they reveal anything that is, in principle, unobservable by such methods.

A final point concerning brain imaging’s threat to privacy is that brain imaging can provide information, but it is up to individuals and society to decide whether and how to use the information provided. For example, the question of whether brain imaging is capable of revealing unconscious racial bias in prospective jurors, as discussed earlier, is separate from the question of whether the courts should use such information in jury selection.

Safety of neurotechnologies

Safety is a concern that is crucial to the assessment of the ethical, legal, and social implications of any neurotechnology—be it psychopharmacology brain stimulation or high-field MRI. As with privacy concerns, there are precedents that provide a framework for addressing safety-related concerns as well. Methodologies for assessing risk and for relating risk to benefit have already been developed and used for a wide variety of drugs and procedures within the clinical neurosciences and in other fields of medicine. This includes drugs and procedures intended purely for enhancement purposes.

Most people find it reasonable to hold enhancements to a higher standard of safety than treatments. In terms of the risk-benefit ratio, this is because we assume that treatments have greater benefits than enhancements; the value of returning someone to health is greater than the value of making a healthy person even better. Yet little is known about the long-term safety of using neuropsychiatric medications or neurotechnology for enhancement. Indeed, relatively little is known about the long-term effects—both efficacy- and safety-wise—of many neuropsychiatric treatments, and evidence concerning their effects on normal, healthy subjects is generally confined to early, short-term clinical trials.

The safety of enhancement has recently attracted attention in the neuroethics literature—and deservedly so. Of particular concern have been the risks associated with prescription stimulants, including heart attack, psychosis, and addiction. Of course, the question of how to weigh safety against potential benefits and the methods for assessing safety are essentially the same, whether one is considering cognitive enhancement or cosmetic surgery.

Fairness of brain enhancement

Issues of competition and fairness arise mainly in connection with enhancement, as mental ability has intrinsic value in its own right but is also a positional good, meaning its value is determined relative to the value of others. In competitive situations, from college admissions testing to chess championships, brain enhancements could confer unfair advantage. One might be willing to accept the fairness of an enhanced admission test score for an individual who intends to continue using brain enhancement, as that score truly reflects the level of ability the individual is likely to bring to his or her studies. If someone were to use a temporary enhancer to improve a test score and then stop enhancing, however, this would be undeniably unfair.

Another way that neurotechnology can lead to unfairness is related to socioeconomic disparities. Brain enhancements have so far been more available to wealthier and better-connected members of society. In a world where basic health care, education, and personal safety cannot be guaranteed to all, it seems unlikely that brain enhancements will be equitably distributed.

Finally, while brain enhancement can be helpful to users, it can also put nonusers at a disadvantage. Take, for example, the situation that would occur when one worker in an office uses modafinil to extend his work hours on a regular basis and his colleague then feels pressure from the boss to be as productive as his enhanced co-worker­.[48]

Autonomy and brain interventions

Pressure to use brain enhancements need not be implicit, as in the example just given. Fitness for duty in the military can depend on use of psychopharmacology. From a purely consequentialist point of view, sufficiently high benefits to society should tip the moral balance in favor of enhancing the wakefulness of pilots or the manual dexterity of surgeons. Yet most of us sense a troubling violation of autonomy in such scenarios.

Similarly, involuntary enhancement of criminal offenders to improve their personality, mood, and self-control presents us with another set of tradeoffs between potentially desirable outcomes and troubling infringement of personal autonomy. If these treatments can enable offenders to live outside of prison and can protect society against crime, then the “benefit” side of the equation is substantial. State-imposed psychopharmacology, however, poses a relatively new kind of limitation on offenders’ autonomy. In contrast to the restrictions imposed by incarceration, which mainly concern physical restrictions, brain interventions would restrict offenders’ abilities to think, feel, and react as they normally would.

Methodological and epistemological challenges

Optimism about the utility of applied neuroscience must be squared with methodological and epistemological problems, as well as ethical concerns. For example, functional imaging data are derived from highly structured laboratory conditions using young, healthy, and compliant volunteers, often college students. Taking these data into the field where there are inevitably vast and highly varied influences on cognition and emotion carries a wide range of risks. The epistemological challenges return us to the most basic problems of modern philosophy since Descartes:[49] What is subjectivity, and can it be known from the “outside”?

What does it mean to deceive and how is self-deception possible? Can we have moral responsibility if our behavior is caused by processes in a physical brain? Yet it may not be necessary to resolve these philosophical conundrums to achieve practical application of neuroscience, just as unresolved profound mysteries about the nature of the universe have not prevented experimental, applied science from advancing rapidly since the Enlightenment. Thus doubts about philosophical coherence are no excuse for failing to confront neuroethical issues, though the precise form they will take over the next decades may be hard to anticipate.

Martha J. Farah is the Walter H. Annenberg professor of natural sciences at the University of Pennsylvania, where she directs the Center for Neuroscience & Society. Jonathan D. Moreno is a Senior Fellow at the Center for American Progress, the editor in chief of Science Progress, the David and Lyn Silfen University professor of ethics at the University of Pennsylvania’s Perelman School of Medicine, and a member of the Center for Neuroscience and Society at the University of Pennsylvania.


Further Reading

Committee to Review the Scientific Evidence on the Polygraph (National Research Council (U.S.), National Research Council (U.S.). Board on Behavioral Cognitive and Sensory Sciences., et al. (2003). The polygraph and lie detection. Washington, D.C., National Academies Press.

Floel, A., G. Garraux, et al. (2008). “Levodopa increases memory encoding and dopamine release in the striatum in the elderly.” Neurobiology of Aging 29(2): 13p.

Hyman, S. E. (2004). “Introduction: the brain’s special status.” U 6(4): 9-12.

Iacoboni, M. (2007). This is your brain on politics. New York Times. New York. November 11, 2007.

Lindström, M. (2008). Buy ology : Truth and Lies About Why We Buy. New York, Doubleday.

Turner DC, Sahakian, B.J.. (2008). The cognition-enhanced classroom. Reshaping the human condition: exploring human enhancement. D. H. Zonneveld L, Ringoir D, The Hague: Rathenau Institute: 107–113.



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[34] Moreno, J. D. (2006). Mind Wars: Brain Research and National Defense. New York, Dana Press.

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[38] Rasmussen, N. (2008). On Speed : The Many Lives of Amphetamine. New York, New York University Press.

[39] Caldwell, J. A. and J. L. Caldwell (2005). Fatigue in military aviation: an overview of US military-approved pharmacological countermeasures. Aviation Space Environmental Medical.76(7 Suppl): C39-51.

[40] Thompson, M. (2008). America’s Medicated Army. Time 171(24): 138-42.

[41] Northrup Grumann Corporation. (2008). Northrop Grumman-Led Team Awarded Contract to Develop Electronic Binoculars That Use Brain Activity to Detect Threats. Linthicum, Maryland, Northrop Grumann Corporation. 2010.

[42] Medical University of South Carolina. (2002). Press Release. Charleston, South Carolina, Medical University of South Carolina.

[43] Nelson, J. T. (2007). Enhancing Warfighter Cognitive Abilities with Transcranial Magnetic Stimulation: a Feasibility Analysis. Air Force Research Laboratory (Technical Report AFRL-HE-WP-TR-2007-0095).

[44] Gross, M. (2010). Medicalized Weapons and Modern War. The Hastings Center Report 40(1): 34-43.

[45] Moreno, J. D. (2006). Mind Wars: Brain Research and National Defense. New York, Dana Press.

[46] Canli T, Amin Z. Neuroimaging of emotion and personality: scientific evidence and ethical considerations. Brain Cognition. 2002 Dec;50(3):414-31.

[47] Hamer, D. (2002). Rethinking behavior genetics. Science 298(5591): 71-72.

[48] See for a discussion of worker protections: Appel, J. M. (2008). When the boss turns pusher: a proposal for employee protections in the age of cosmetic neurology. Journal of Medical Ethics 34(8): 57-60.

[49] Moreno, J.D. (2003). Neuroethics: An agenda for science and society. Nature Reviews Neuroscience, 4, 149-153.


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