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Moral Enhancement Requires Multiple Virtues

Toward a Posthuman Model of Character Development

Published online by Cambridge University Press:  04 December 2014

JAMES J. HUGHES
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Abstract:

Some of the debates around the concept of moral enhancement have focused on whether the improvement of a single trait, such as empathy or intelligence, would be a good in general, or in all circumstances. All virtue theories, however, both secular and religious, have articulated multiple virtues that temper and inform one another in the development of a mature moral character. The project of moral enhancement requires a reengagement with virtue ethics and contemporary moral psychology to develop an empirically grounded model of the virtues and a fuller model of character development. Each of these virtues may be manipulable with electronic, psychopharmaceutical, and genetic interventions. A set of interdependent virtues is proposed, along with some of the research pointing to ways such virtues could be enhanced.

Keywords

moral enhancementcharactervirtue

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Type
Special Section: How Moral Is (Moral) Enhancement?
Information
Cambridge Quarterly of Healthcare Ethics , Volume 24 , Issue 1 , January 2015 , pp. 86 - 95
Copyright
Copyright © Cambridge University Press 2014 

Beyond Single-Virtue Enhancement

Recent debates about moral enhancement have focused on the relative benefits of enhancing moral sentiments like empathy versus enhancing cognition and moral reasoning. On one side, Ingmar Persson and Julian SavulescuFootnote 1,Footnote 2 have focused on the pressing need to enhance altruistic sentiments like empathy, especially in light of the danger that cognitive enhancement could superempower malevolent individuals. On the other side, John HarrisFootnote 3,Footnote 4 and Fabrice JotterandFootnote 5 have argued that enhancing moral sentiments would constrain human freedom and produce a faux morality, and that we should instead focus on the enhancement of cognition and moral reasoning.

The debate is odd in light of the history of moral philosophy, because it seems unaware of the integrative emphasis in the virtue ethics traditions. In contrast to the reductive ethics of, for instance, Kant, virtue traditions have argued that a fully mature moral character requires the cultivation of multiple interdependent virtues that complement and balance one another. In the Buddhist tradition, the simultaneous cultivation of wisdom and compassion is seen as the core of character development, with subsidiary virtues broken down into dozens of emotional, behavioral, and cognitive abilities that, when developed, all contribute to awakening. Aristotle’s dozens of virtues all have extreme versions that become vices. Excessive courage can lead to foolhardiness, and excessive modesty, shyness. Excessive altruism can result in self-destructiveness. Too much prudence and self-control can result in sins of inaction. For Aristotle, all the virtues need, therefore, to be directed by phronesis, or practical wisdom. Adam Grant and Barry SchwartzFootnote 6 recently reviewed the substantial empirical evidence for nonmonotonic effects from all kinds of psychological traits and moral virtues and concluded that psychological research should take more heed of the Aristotelian (and Buddhist, and pervasive) idea of a golden mean achieved by the balance of multiple virtues.

Some in the moral enhancement debates also point to the need for a more complete picture of the virtues, but they presume that enhancement technologies will never be able to improve all these faculties. For instance, Fabrice Jotterand argues, “The way human beings make moral decisions requires the interaction of a complex network of emotional, cognitive, and motivational processes that cannot be reduced just to moral emotions or technological control (moral capacity) but also to practical reasoning (i.e., the source of moral content).”Footnote 7 But he sees moral enhancement as being useful only in improving the moral emotions and not in improving practical reasoning. Conversely Barbro FrödingFootnote 8 argues that cognitive enhancement can be integrated into a fuller model of Aristotelian character development, but she focuses only on the possibilities for improving cognition and the learning of good habits. John Shook,Footnote 9 on the other hand, points to five moral capacities—three of which are cognitive enhancements (sensitivity to the moral features of situations, thoughtfulness about doing the moral thing, and a capacity for making accurate moral judgments), in addition to the enhancement of moral intentions and of self-control—that should and can be targets of moral enhancement.

In this article I sketch out a core model of the virtues to be enhanced and then outline how an approach to enhanced character development could use the enhancement of more than one virtue to achieve better results than one-dimensional moral enhancement.

Enumerating the Virtues to Be Enhanced

One can imagine the goal of moral enhancement as the creation of a control panel for moral sentiment and cognition, with sliders or dials representing the requisite neurological traits needing to be tuned. In order to create this control panel, we need to identify which dials we will need. These categories will need to correspond to both the concepts of virtues in the philosophical and religious literature and the emerging psychometric and neuroscientific understandings of cognition and behavior. For this project to be successful, William CasebearFootnote 10 is hopefully correct when he says that there is a rough “consilience” between neuroscience and the moral psychology of virtue ethics.

One attempt to reduce the huge variety of virtue schemas in the world’s philosophies and religions to testable, empirical traits was launched in the 2000s by the psychologist Martin Seligman and others in the field of “positive psychology.” Their work resulted in a model of six “character strengths,” each with their own subsidiary list of virtues.Footnote 11

  1. 1) Wisdom and knowledge: creativity, curiosity, judgment, love of learning, and perspective

  2. 2) Courage: bravery, perseverance, honesty, and zest

  3. 3) Humanity: love, kindness, and social intelligence

  4. 4) Justice: teamwork, fairness, and leadership

  5. 5) Temperance: forgiveness, humility, prudence, and self-regulation

  6. 6) Transcendence: appreciation of beauty and excellence, gratitude, hope, humor, and spirituality

Seligman and his colleagues developed questions designed to allow respondents to self-assess the degree to which they possessed each of these 24 virtues and made the questions available through the VIA Institute. Half a million people have taken these tests online, creating an enormous database for evaluating whether the a priori structure of these traits corresponds to the empirical structure in individual self-assessments. McGrathFootnote 12 analyzed the VIA survey data and found five underlying sets of virtues:

  1. 1) Interpersonal strengths: fairness, forgiveness, kindness, receptivity, teamwork, modesty, and love

  2. 2) Emotional strengths: humor, social skills, creativity, bravery, and prudence

  3. 3) Intellectual pursuits: love of learning, beauty, and curiosity

  4. 4) Restraint: judgment, perseverance, perspective, and honesty

  5. 5) Future orientation: positivity, future-mindedness, self-regulation, and spirituality

In other words, in general, people who saw themselves as strong in forgiveness were also more likely to see themselves as strong in fairness, even though these had been conceptualized as belonging to two separate categories of virtues in the VIA scheme. The statistical disaggregation of traits in all such studies is open to some interpretation, however, as all the strengths are correlated to some degree. Using VIA data from 332 twins, Jessica Shryack, Michael Steger, Robert Krueger, and Christopher KallieFootnote 13 found only three core clusters of strengths: (1) interpersonal strengths, such as kindness and fairness; (2) temperance strengths, such as perseverance and self-regulation; and (3) intellectual strengths, such as creativity and judgment.

This empirical method is the same that has been used to generate the most popular of the many models of personality in psychology: the five-factor or OCEAN model.Footnote 14 The OCEAN model was derived by looking for statistical structures in the hundreds of personality inventory questions and found a stable clustering around five attributes: open-mindedness, conscientiousness, extraversion, agreeableness, and neuroticism. These five traits have in turn been correlated with hundreds of attitudes and behaviors,Footnote 15 including subjective well-being, volunteering, occupational choice and success, and peer and family relationships. The OCEAN personality traits are relatively stable over time, and twin studies show that they are about half genetically determined. This provides strong evidence for interpreting these personality traits as having neurobiological bases, albeit complex ones with multiple genes and neurochemicals in play. Xingguang Luo et al.Footnote 16 have, for instance, found a number of genes correlated to the OCEAN traits of agreeableness and conscientiousness.

When we compare the empirical structure of personality traits to the empirical structure of virtues, we see that there is some correlation. Craig MacDonald, Miles Bore, and Don MunroFootnote 17 recently explored the correlations between the OCEAN and the VIA models and found four underlying virtue-psychology sets: positivity, intellect, conscientiousness, and niceness. Positivity (including emotional strengths such as a sense of humor and hopefulness) was negatively correlated to the OCEAN trait of neuroticism and is strongly correlated with happiness. Intellect (including the intellectual virtues of love of learning and curiosity) was correlated to the OCEAN trait of open-mindedness. Open-mindedness has, in turn, been found to be correlated with IQ.Footnote 18 Conscientiousness (including the virtues of restraint and honesty) was of course related to conscientiousness. Niceness, which encompasses the interpersonal virtues of empathy, kindness, and receptivity, was correlated with the personality trait of agreeableness.

In the following section, therefore, I discuss a minimal model of moral enhancement focused on the manipulation of four basic capacities based loosely on the accumulating evidence of an empirical psychometric structure to the virtues with some correspondence to underlying neurogenetics and neurochemistry:

  1. 1) Self-control: sophrosyne, restraint, conscientiousness, and temperance

  2. 2) Niceness: agreeableness, extraversion, empathy, and fairness

  3. 3) Intelligence: phronesis, open-mindedness, curiosity, love of learning, and prudence

  4. 4) Positivity: (lack of) neuroticism, emotional self-regulation, positivity, bravery, and humor

These categories roughly correspond to the four cardinal virtues of Plato and Aquinas—temperance, justice, prudence, and courage—although each encompasses more than the classical categories. These categories encompass both the emotive and the cognitive dimensions of moral enhancement that have been discussed in the literature so far but also include virtues that have not been discussed, that is, self-control and positivity.

Four Virtues to Be Enhanced

Self-Control

The ability to exercise self-control, in particular in relation to vices such as anger, intoxication, and sensual pleasure, has been a virtue in almost every system of moral thought, from Greek philosophy and the Abrahamic faiths to Hinduism and Buddhism, and Confucianism and Taoism. Neuroscience has been illuminating the mechanisms involved in sustaining and exercising self-control, and the role of distractions and desires that overwhelm it. Our capacity for self-control as children, which is correlated with variations in dopamine genesFootnote 19 and the personality trait of conscientiousness, predicts our capacity for self-control as adults. A lower capacity for self-control is correlated with more drug and alcohol use, sexual risk taking, and violence.Footnote 20 Attention deficit disorder (ADD), characterized by low mindfulness and self-control, is strongly heritable and is linked to variations in the dopamine- and serotonin-regulating genes.Footnote 21

Fortunately we have a variety of behavioral interventions, drugs, and information technologies that are already helping us exercise more mindfulness and self-control. Attentiveness to fatigue and blood sugar helps guard against the “ego depletion” that weakens willpower.Footnote 22 Stimulant medications improve impulse control by heightening dopaminergic responses to tasks at hand and by dampening distractions. The alertness drug modafinil also increases deliberation.Footnote 23,Footnote 24

On the side of suppressing bad habits, we also have a growing armamentarium. Bariatric surgery is the most effective form of weight control, and drugs and devices that suppress appetite, like stomach pacemakers, will soon be available. Alcoholics can take naltrexone to suppress alcohol cravings, and vaccines to block the effects of cocaine and nicotine are under development. A number of cognitive enhancement drugs, including modafinil and methylphenidate, have shown some promise in the treatment of drug dependency.Footnote 25 In some places, convicted sexual offenders are offered testosterone suppression therapies that reduce sexual compulsion. Julian Savulescu and Anders SandbergFootnote 26 have suggested that the administration of oxytocin, vasopressin, and testosterone might be useful as an adjunct to marital therapy, reducing infidelity.

On the other hand, too much self-control can inhibit desirable risk taking, spontaneity, and life enjoyment. Although conscientiousness is generally a predictor of successful task performance, those highest in conscientiousness perform tasks less well because they are prone to perfectionism.Footnote 27 Conscientious people also suffer much more if they become unemployed.Footnote 28 For enhanced self-control to lead to a full and flourishing life, it needs the modulating influence of other virtues, such as empathy, prudence, and joie de vivre.

Niceness

As with self-control, there is strong evidence that our capacity for compassion and empathy is modulated by neurological structures like mirror neurons, which cause us to feel the experiences of others, and by neurochemicals like oxytocin, which heighten empathy and trust. The personality trait of agreeableness, which is about half genetically determined and is presumably connected with underlying neurochemistry and morphology, is correlated with empathyFootnote 29 and volunteering.Footnote 30 Variations in oxytocin receptor genes are likewise correlated with the ability to empathize with others’ feelings.Footnote 31 Oxytocin supplementation improves the ability to read social cues,Footnote 32,Footnote 33 put trust in others,Footnote 34 and express generosity in social games.Footnote 35 MDMA (Ecstasy) stimulates the release of oxytocin,Footnote 36 and its users report feeling more love and compassion.

Similarly, there is strong evidence that our desire for fairness, or, more precisely, our desire to punish cheaters, is biologically innate. The fairness impulse is modulated by variations in serotonin receptors and is sensitive to the level of serotonin in the brain.Footnote 37 Brain scans have also found this impulse to uphold fairness, or to punish cheaters, to be rooted in activity in both the emotion and the cognition parts of the brain.Footnote 38

On the other hand, those who are too high on the niceness scale can also suffer. For instance, although moderate amounts of volunteering are associated with subjective well-being, those who volunteer the most are less happy.Footnote 39 Oxytocin supplementation also can have perverse effects, in increasing in-group solidarity at the expense of out-group altruism.Footnote 40 Polymorphisms in serotonin genes are correlated with the willingness to make utilitarian decisions that cause harm to others,Footnote 41 and boosting serotonin with selective serotonin reuptake inhibitors (SSRIs) has been found to increase our aversion to harming others. But this aversion can also lead to unwillingness to punish cheaters and wrongdoers.Footnote 42 In itself, the impulse to punish wrongdoers may be ethical (when focused on bankers and CEOs, for instance) or unethical (when focused on immigrants and minorities); prudent reflection shapes the moral target of the fairness impulse.

As Harris and others have opined, moral sentiments like empathy and fairness are inadequate without entrainment with moral reasoning, knowledge, and discriminating wisdom. Although the contrary effects of empathy and fairness enhancement drugs have been pointed to as a sign that the project of moral enhancement is impossible, within a framework of multivirtue character development, we can argue that these effects should be modulated and entrained in positive directions by the exercise of other virtues.

Intelligence

ShookFootnote 43 argues for the importance of three cognitive capacities or intellectual virtues that should and can be targets of moral enhancement: sensitivity to the moral features of situations, thoughtfulness about doing the moral thing, and a capacity for making accurate moral judgments. Progress in the chemical and electrical enhancement of cognition, learning, memory, and decisionmaking will contribute to the enhancement of these moral capabilities.

Again, there is substantial evidence for genes and corresponding neurochemicals that influence our cognitive abilities.Footnote 44 The personality trait of openness to experience is about half genetically determinedFootnote 45 and is correlated with creativity,Footnote 46 intelligence,Footnote 47 curiosity,Footnote 48 and a love of learning.Footnote 49 Openness to experience is also associated with activity in the dorsolateral prefrontal cortex,Footnote 50 supporting its connection to intelligence. Although the IQ-related genes are myriad, and all have minor effects, it is possible that these discoveries will lead to drug cocktails and gene therapies with significant impacts. For instance, switching off the Nogo Receptor 1 gene, which regulates neural plasticity, returns older mice brains to adolescent levels of plasticity.Footnote 51 Drug therapies are also being explored for cognitive enhancement. Nicotine, for instance, has been shown to enhance attention, response time, and memory.Footnote 52 Modafinil increases reaction time, logical reasoning, and problem solving, whereas methylphenidate improves the performance of novel tasks and speeds up planning for complex tasks.Footnote 53 Research is also proceeding in the enhancement of cognition and learning with direct electrical stimulation of the brain through the skull, and with the implantation of brain-machine interfaces.

However, too much intelligence can have its drawbacks. Too much deliberation can be debilitating, as is demonstrated by Antonio Damasio’sFootnote 54 research on people who have brain damage that prevents their access to emotions, and who are thereby unable to make decisions. Deliberation uninformed by moral sentiments can lead to perversely machine-like moral decisionmaking.Footnote 55 Likewise, the use of excessive amounts of cognitive-enhancing stimulants can overstimulate dopamine and norepinephrine and impair learning, memory, and neural plasticity.Footnote 56 The intellectual virtues need to find their own golden mean and need to be tempered with and entrained by self-control, empathy, and mindfulness.

Positivity

David Pearce’s 1995 essay “The Hedonistic Imperative,”Footnote 57 based on utilitarian logic, proposes that the central goal of bioenhancement should be the design of drugs, nanotechnology, and genetic engineering to eliminate pain and to create the maximum possible amount of happiness and pleasure that we are capable of. The proposal is, of course, contrary to most virtue ethics schemes, which generally posit that happiness is not a goal in itself, and that the highest form of happiness, eudaemonia, comes from living an engaged and moral life. Pearce attempts to meet the objections that maximizing pleasure and happiness would lead to passivity and ennui by suggesting that we will recalibrate the brain’s happiness set point, keeping ourselves motivated and engaged with gradients of bliss rather than with the current, duller emotional treadmill. If this is possible, we could achieve a form of hypereudaemonia, a fulfilling, engaged, and moral life that is also full of pleasure.

There is some evidence to support the idea that at least the most happy humans today are also the most engaged. Self-reported happiness is broadly correlated with having friends and getting and staying married, volunteering, performing well at work,Footnote 58 being tolerant of social difference,Footnote 59 wearing seatbelts,Footnote 60 and condemning unethical behavior (e.g., bribery and tax evasion).Footnote 61 On the other hand, the very happiest 10 percent appear to sacrifice less to get education, earn less, participate politically less frequently, have poorer health, and be subject to more errors of overoptimistic assessments of risk.Footnote 62 In other words, being too content can lead to inattention to temperance, and to the civic and intellectual virtues.

So, as Mark WalkerFootnote 63 argues in Happy-People-Pills for All, even if happiness is not the sole virtue, and if being too happy can have adverse consequences, possessing an above-average but not extreme amount of happiness is a virtue in itself and generally does support many other-regarding virtues. Within a virtues model of character development that recognizes that flourishing requires more than pleasure, a program of moral enhancement should include permanent mood enhancement. Although the efficacy of antidepressants and mood modification is highly contested, we are nonetheless making slow progress in understanding the neurochemistry of happiness and are beginning to understand the practices, drugs, and devices that can boost the happiness set point. The personality trait of neuroticism, which again is highly heritable and stable across the life course, is the principal correlate of the happiness set point. A study of 2,500 twins narrowed in on variations in a serotonin transporter gene (5-HTTLPR) as being the principal genetic correlate of life satisfaction,Footnote 64 whereas another study suggests that about 12–18 percent of happiness is predicted by genetic polymorphisms.Footnote 65 Many compounds beyond SSRIs are being explored for mood-enhancement effects, including cannabis, nicotine, oxytocin, ketamine, MDMA, and psychedelics such as psilocybin. Episodic use of psilocybin, for instance, is associated with lower risks of mental health problemsFootnote 66 and the alleviation of fear, anxiety, and other negative emotions.Footnote 67

A Posthuman Approach to Character Development

Given the interdependence of the virtues, a program of posthuman virtue enhancement will require not just the boosting of specific sentiments and capabilities but their conscious channeling within a program of neurotechnologically facilitated moral evaluation, education, and entrainment. Psychiatry has begun to map the methods for diagnosing character flaws, and to determine the appropriate behavioral and chemical interventions to bring individuals lacking in self-control, empathy, intelligence, or positivity closer to the norm. But the average person has far fewer of these capabilities than he or she would like, or than are called for in a virtues ethics framework. A posthuman model of moral enhancement goes beyond simply therapeutic redress of isolated flaws to the achievement of a rich and rare level of flourishing. In Buddhist psychology, for instance, there are numerous diagnostic categories for personality flaws such as sexual desires or pride, and compensatory meditation exercises are prescribed to address them. Once the most glaring weaknesses are addressed, there is still a long road prescribed to cultivate the myriad virtues required for reaching the more rare and difficult perfections of character.

Unfortunately we are all burdened to a greater or lesser extent by the weaknesses of body and mind that make practicing these virtues difficult, burdens that can be overcome with moral enhancement. As Fröding argues, “if these cognitive shortcomings could be compensated for, or balanced, through the use of safe and voluntary enhancement techniques, then it would be morally desirable to do so. Indeed, it could well be the case that a combination of cognitive enhancement and virtue could make virtue ethics more convincing.”Footnote 68 By embracing a fuller, empirically grounded model of the multiple virtues required for moral enhancement, we can also make the moral enhancement project more convincing.

References

Notes

1. Persson, I, Savulescu, J. Moral transhumanism. The Journal of Medicine and Philosophy 2010;35(6):656–69.CrossRefGoogle ScholarPubMed

2. Persson, I, Savulescu, J. The perils of cognitive enhancement and the urgent imperative to enhance the moral character of humanity. Journal of Applied Philosophy 2008;25(3):162–77.Google Scholar

3. Harris, J. “Ethics is for bad guys!” Putting the “moral” into moral enhancement. Bioethics 2013;27(3):169–73.Google Scholar

4. Harris, J. Moral enhancement and freedom. Bioethics 2011;25(2):102–11.Google Scholar

5. Jotterand, F. “Virtue engineering” and moral agency: Will post-humans still need the virtues? AJOB Neuroscience 2011;2(4):3–9.Google Scholar

6. Grant, AM, Schwartz, B. Too much of a good thing: The challenge and opportunity of the inverted U. Perspectives on Psychological Science 2011;6(1):61–76.Google Scholar

7. See note 5, Jotterand 2011.

8. Fröding, BEE. Cognitive enhancement, virtue ethics and the good life. Neuroethics 2011;4(3):223–34.Google Scholar

9. Shook, J. Neuroethics and the possible types of moral enhancement. AJOB Neuroscience 2012;3(4):3–14.Google Scholar

10. Casebear, W. Moral cognition and its neural constituents. Perspectives Nature Neuroscience 2003;4:841–6.Google Scholar

11. Peterson, CP, Seligman, M. Character Strengths and Virtues: A Handbook and Classification. Washington, DC: APA Press; 2004.Google Scholar

12. McGrath, R. Scale- and item-level factor analyses of the VIA inventory of strengths. Assessment 2012 Feb;21(1):4–14.Google Scholar

13. Shryack, J, Steger, MF, Krueger, RF, Kallie, CS. The structure of virtue: An empirical investigation of the dimensionality of the virtues in action inventory of strengths. Personality and Individual Differences 2010;48:714–19.Google Scholar

14. Digman, JM. Personality structure: Emergence of the five-factor model. Annual Review of Psychology 1990;41:417–40.Google Scholar

15. Ozer, DJ, Benet-Martinez, V. Personality and the prediction of consequential outcomes. Annual Review of Psychology 2006;57:401–21.Google Scholar

16. Luo, X, Kranzler, HR, Zuo, L, Zhang, H, Wang, S, Gelernter, J. CHRM2 variation predisposes to personality traits of agreeableness and conscientiousness. Human Molecular Genetics 2007;16(13):1557–68.Google Scholar

17. Macdonald, C, Bore, M, Munro, D. Values in action scale and the big 5: An empirical indication of structure. Journal of Research in Personality 2008;42(4):787–99.Google Scholar

18. Bartels, M, van Weegen, F, van Beijsterveldt, CM, Carlier, M, Polderman, TJC, Hoekstra, RA, Boomsma, DI. The five factor model of personality and intelligence: A twin study on the relationship between the two constructs. Personality and Individual Differences 2012;53(4):368–73.Google Scholar

19. Blasi, G, Lo Bianco, L, Taurisano, P, Gelao, B, Romano, R, Fazio, L, et al. Functional variation of the dopamine D2 receptor gene is associated with emotional control as well as brain activity and connectivity during emotion processing in humans. Journal of Neuroscience 2008;29(47):14812–19.Google Scholar

20. See note 15, Ozer, Benet-Martinez 2006.

21. Faraone, SV, Mick, E. Molecular genetics of attention deficit hyperactivity disorder. Psychiatric Genetics 2010;33(1):159–80.Google Scholar

22. Baumeister, RF, Vohs, KD, Tice, DM. The strength model of self-control. Current Directions in Psychological Science 2007;16(6):351–5.Google Scholar

23. Sandberg, A. Cognition enhancement: Upgrading the brain. In Savulescu, J, Kahane, G, ter Meulen, R, eds. Enhancing Human Capacities. Oxford: Wiley-Blackwell; 2011.Google Scholar

24. Killgore, WD, Kahn-Greene, ET, Grugle, NL, Killgore, DB, Balkin, TJ. Sustaining executive functions during sleep deprivation: A comparison of caffeine, dextroamphetamine, and modafinil. Sleep 2009 Feb;32(2):205–16.CrossRefGoogle ScholarPubMed

25. Sofuoglua, M, DeVito, EE, Waters, AJ, Carroll, KM. Cognitive enhancement as a treatment for drug addictions. Neuropharmacology 2013;64:452–63.Google Scholar

26. Savulescu, J, Sandberg, A. Neuroenhancement of love and marriage: The chemicals between us. Neuroethics 2008;1:31–44.Google Scholar

27. See note 6, Grant, Schwartz 2011.

28. Boyce, CJ, Wood, A, Brown, GDA. The dark side of conscientiousness: Conscientious people experience greater drops in life satisfaction following unemployment. Journal of Research in Personality 2010;44:535–9.Google Scholar

29. Del Barrio, V, Aluja, A, Garcia, LF. Relationship between empathy and the big five personality traits in a sample of Spanish adolescents. Social Behavior and Personality 2004;32(7):677–82.CrossRefGoogle Scholar

30. Carlo, G, Okun, MA, Knight, GP, de Guzman, MRT. The interplay of traits and motives on volunteering: Agreeableness, extraversion, and prosocial value motivation. Personality and Individual Differences 2005;38:1293–305.Google Scholar

31. Rodrigues, SM, Saslow, LR, Garcia, N, John, OP, Keltner, D. Oxytocin receptor genetic variation relates to empathy and stress reactivity in humans. Proceedings of the National Academy of Sciences 2010;107(31):13936–41.Google Scholar

32. Domes, G, Heinrichs, M, Michel, A, Berger, C, Herpertz, SC. Oxytocin improves “mind-reading” in humans. Biological Psychiatry 2007;61:731–3.Google Scholar

33. Guastellaemail, AJ, Einfeld, SL, Gray, KM, Rinehart, NJ, Tonge, BJ, Lambert, TJ, et al. Intranasal oxytocin improves emotion recognition for youth with autism spectrum disorders. Biological Psychiatry 2010;67(1):692–4.Google Scholar

34. Kosfeld, M, Heinrichs, M, Zak, PJ, Fischbacher, U, Fehr, E. Oxytocin increases trust in humans. Nature 2005 June 2;435:673–6.Google Scholar

35. Zak, PJ, Stanton, AA, Ahmadi, S. Oxytocin increases generosity in humans. PLoS One 2007;2(11):e1128.Google Scholar

36. Thompson, MR, Callaghan, PD, Hunt, GE, Cornish, JL, McGregor, IS. A role for oxytocin and 5-HT(1A) receptors in the prosocial effects of 3,4 methylenedioxymethamphetamine. Neuroscience 2007;146(2):509–14.Google Scholar

37. Crockett, MJ, Clark, L, Tabibnia, G, Lieberman, MD, Robbins, TW. Serotonin modulates behavioral reactions to unfairness. Science 2008;320(5884):1739.Google Scholar

38. Tabibnia, G, Lieberman, MD. Fairness and cooperation are rewarding evidence from social cognitive neuroscience. Annals of the New York Academy of Sciences 2007;1118:90–101.Google Scholar

39. Windsor, TD, Anstey, KJ, Rodgers, B. Volunteering and psychological well-being among young-old adults: How much is too much? The Gerontologist 2008;48:59–70.Google Scholar

40. De Dreu, CKW, Greer, LL, Van Kleef, GA, Shalvi, S, Handgraaf, MJJ. Oxytocin promotes human ethnocentrism. Proceedings of the National Academy of Sciences 2011;108(4):1262–6.CrossRefGoogle ScholarPubMed

41. Marsh, AA, Crowe, SL, Yu, HH, Gorodetsky, EK, Goldman, D, Blair, RJR. Serotonin transporter genotype (5-HTTLPR) predicts utilitarian moral judgments. PLoS ONE 2011;6(10):1–5.Google Scholar

42. Crockett, MJ, Clark, L, Hauser, MD, Robbins, TW. Serotonin selectively influences moral judgment and behavior through effects on harm aversion. Proceedings of the National Academy of Sciences 2010;107(40):17433–8.Google Scholar

43. Shook, J. Neuroethics and the possible types of moral enhancement. AJOB Neuroscience 2012;3(4):3–14.Google Scholar

44. Haworth, CMA, Wright, MJ, Martin, NW, Martin, NG, Boomsma, DI, Bartels, M, et al. A twin study of the genetics of high cognitive ability selected from 11,000 twin pairs in six studies from four countries. Behavior Genetics 2009;39:359–70.CrossRefGoogle Scholar

45. Jang, KL, Livesly, WJ, Vemon, PA. Heritability of the big five personality dimensions and their facets: A twin study. Journal of Personality 1996;64(3):577–92.Google Scholar

46. McCrae, RR. Creativity, divergent thinking, and openness to experience. Journal of Personality and Social Psychology 1987;52(6):1258–65.Google Scholar

47. Furnham, A, Chamorro-Premuzic, T. Personality, intelligence, and general knowledge. Learning and Individual Differences 2006;16:79–90.Google Scholar

48. Mussell, P. Epistemic curiosity and related constructs: Lacking evidence of discriminant validity. Personality and Individual Differences 2010;49(5):506–10.Google Scholar

49. Furnham, A, Swami, V, Arteche, A, Chamorro-Premuzic, T. Cognitive ability, learning approaches and personality correlates of general knowledge. Educational Psychology 2008;28(4):427–37.Google Scholar

50. DeYoung, CG, Peterson, JB, Higgins, DM. Sources of openness/intellect: Cognitive and neuropsychological correlates of the fifth factor of personality. Journal of Personality 2005;73(4):825–58.CrossRefGoogle ScholarPubMed

51. Akbik, FV, Bhagat, SM, Patel, PR, Cafferty, WB, Strittmatter, SM. Anatomical plasticity of adult brain is titrated by Nogo Receptor 1. Neuron 2013;77(5):859–66.Google Scholar

52. Heishman, SJ, Kleykamp, BA, Singleton, EG. Meta-analysis of the acute effects of nicotine and smoking on human performance. Psychopharmacology 2010;210(4):453–69.Google Scholar

53. Bagot, KS, Kaminer, Y. Efficacy of stimulants for cognitive enhancement in non-attention deficit hyperactivity disorder youth: A systematic review. Addiction 2014;109(4):547–57.Google Scholar

54. Damasio, A. Descartes’ Error: Emotion, Reason, and the Human Brain. New York: Penguin Books; 2005.Google Scholar

55. Michael, K, Young, L, Adolphs, R, Tranel, D, Cushman, F, Hauser, M, et al. Damage to the prefrontal cortex increases utilitarian moral judgements. Nature 2007;446(7138):908–11.Google Scholar

56. Urban, KR, Gao, W-J. Performance enhancement at the cost of potential brain plasticity: Neural ramifications of nootropic drugs in the healthy developing brain. Frontiers in Systems of Neuroscience 2014; available at http://journal.frontiersin.org/Journal/10.3389/fnsys.2014.00038 (last accessed 15 May 2014).Google Scholar

57. Pearce, D. The Hedonistic Imperative; 1995; available at http://www.hedweb.com/hedethic (last accessed 15 May 2014).Google Scholar

58. Oishi, S, Diener, E, Lucas, RE. The optimal level of well-being: Can we be too happy? Perspectives on Psychological Science 2007;2:346–60.Google Scholar

59. Inglehart, R, Foa, R, Peterson, C, Welzel, C. Development, freedom, and rising happiness: A global perspective (1981−2007). Perspectives on Psychological Science 2008;3(4):264–85.Google Scholar

60. Goudie R, Mukherjee S, De Neve JE, Oswald AJ, Wu S. Happiness as a driver of risk-avoiding behavior: A conceptual framework with an application to seatbelt wearing and automobile accidents. Paper no. CEP 1126. Centre for Economic Performance, London School of Economics; 2012.

61. James, HS. Is the just man a happy man? An empirical study of the relationship between ethics and subjective well-being. Kyklos 2011;64(2):193–212.Google Scholar

62. See note 58, Oishi et al. 2007.

63. Walker, M. Happy-People-Pills for All. West Sussex: John Willey & Sons; 2013.Google Scholar

64. De Neve, JE, Christakis, NA, Fowler, JH, Frey, BS. Genes, economics and happiness. Journal of Neuroscience, Psychology, and Economics 2012:5(4):193–211.Google Scholar

65. Rietveld, CA, Cesarini, D, Benjamin, DJ, Koellinger, PD, De Neve, J-E, Tiemeier, H, et al. Molecular genetics and subjective well-being. Proceedings of the National Academy of Sciences 2013;110(24):9692–7.Google Scholar

66. Krebs, TS, Johansen, P-Ø. Psychedelics and mental health: A population study. PLOS One 2013;8(8):1–9.Google Scholar

67. Kraehenmann, R, Preller, KH, Scheidegger, M, Pokorny, T, Bosch, OG, Seifritz, E, et al. Psilocybin-induced decrease in amygdala reactivity correlates with enhanced positive mood in healthy volunteers. Biological Psychiatry; forthcoming; available at http://www.sciencedirect.com/science/article/pii/S0006322314002753 (last accessed 15 May 2014).Google Scholar

68. See note 8, Fröding 2011, at 232.