Jump to content

Psychedelic experience

From Wikipedia, the free encyclopedia
(Redirected from Psychedelic Experience)

A psychedelic experience (known colloquially as a trip) is a temporary altered state of consciousness induced by the consumption of a psychedelic substance (most commonly LSD, mescaline, psilocybin mushrooms, or DMT).[citation needed] For example, an acid trip is a psychedelic experience brought on by the use of LSD, while a mushroom trip is a psychedelic experience brought on by the use of psilocybin. Psychedelic experiences feature alterations in normal perception such as visual distortions and a subjective loss of self-identity, sometimes interpreted as mystical experiences. Psychedelic experiences lack predictability, as they can range from being highly pleasurable (known as a good trip) to frightening (known as a bad trip). The outcome of a psychedelic experience is heavily influenced by the person's mood, personality, expectations, and environment (also known as set and setting).[1]

Researchers have interpreted psychedelic experiences in light of a range of scientific theories, including model psychosis theory, filtration theory, psychoanalytic theory, entropic brain theory, integrated information theory, and predictive processing. Psychedelic experiences are also induced and interpreted in religious and spiritual contexts.

Etymology

[edit]

The term psychedelic was coined by the psychiatrist Humphrey Osmond during written correspondence with author Aldous Huxley and presented to the New York Academy of Sciences by Osmond in 1957.[2] It is derived from the Greek words ψυχή, psychḗ, 'soul, mind' and δηλείν, dēleín, 'to manifest' thus meaning "mind manifesting," the implication being that psychedelics can develop unused potentials of the human mind.[3] The term trip was first coined by US Army scientists during the 1950s when they were experimenting with LSD.[4]

Phenomenology

[edit]

Despite several attempts that have been made, starting in the 19th and 20th centuries, to define common phenomenological structures of the effects produced by classic psychedelics, a universally accepted taxonomy does not yet exist.[5][6]

Visual alteration

[edit]

A prominent element of psychedelic experiences is visual alteration.[5] Psychedelic visual alteration often includes spontaneous formation of complex flowing geometric visual patterning in the visual field.[6] When the eyes are open, the visual alteration is overlaid onto the objects and spaces in the physical environment; when the eyes are closed the visual alteration is seen in the "inner world" behind the eyelids.[6] These visual effects increase in complexity with higher dosages, and also when the eyes are closed.[6] The visual alteration does not normally constitute hallucinations, because the person undergoing the experience can still distinguish between real and imagined visual phenomena, though in some cases, true hallucinations are present.[5] More rarely, psychedelic experiences can include complex hallucinations of objects, animals, people, or even whole landscapes.[5] Visual alterations also include other effects such as afterimages, shifting of color hues, and pareidolia. The appearance of colors and light are usually enhanced.

Mystical experiences

[edit]

A number of studies by Roland R. Griffiths and other researchers have concluded that high doses of psilocybin and other classic psychedelics trigger mystical experiences in most research participants.[7][8][9][10] Mystical experiences have been measured by a number of psychometric scales, including the Hood Mysticism Scale, the Spiritual Transcendence Scale, and the Mystical Experience Questionnaire.[10] The revised version of the Mystical Experience Questionnaire, for example, asks participants about four dimensions of their experience, namely the "mystical" quality, positive mood such as the experience of amazement, the loss of the usual sense of time and space, and the sense that the experience cannot be adequately conveyed through words.[10] The questions on the "mystical" quality in turn probe multiple aspects: the sense of "pure" being, the sense of unity with one's surroundings, the sense that what one experienced was real, and the sense of sacredness.[10] Some researchers have questioned the interpretation of the results from these studies and whether the framework and terminology of mysticism are appropriate in a scientific context, while other researchers have responded to those criticisms and argued that descriptions of mystical experiences are compatible with a scientific worldview.[11][12][13]

A group of researchers concluded in a 2011 study that psilocybin "occasions personally and spiritually significant mystical experiences that predict long-term changes in behaviors, attitudes and values".[14]

Some research has found similarities between psychedelic experiences and non-ordinary forms of consciousness experienced in meditation[15] and near-death experiences.[16] The phenomenon of ego dissolution is often described as a key feature of the psychedelic experience.[17][18][19]

Individuals who have psychedelic experiences often describe what they experienced as "more real" than ordinary experience. For example, the psychologist Benny Shanon, after observing ayahuasca trips, referred to "the assessment, very common with ayahuasca, that what is seen and thought during the course of intoxication defines the real, whereas the world that is ordinarily perceived is actually an illusion."[20] Similarly, the psychiatrist Stanislav Grof described the LSD experience as "complex revelatory insights into the nature of existence… typically accompanied by a sense of certainty that this knowledge is ultimately more relevant and 'real' than the perceptions and beliefs we share in everyday life."[21]

Bad trips

[edit]

A "bad trip" is a highly unpleasant psychedelic experience.[5][22] A bad trip on psilocybin, for instance, often features intense anxiety, confusion, agitation, or even psychotic episodes.[23] Bad trips can be connected to the anxious ego-dissolution (AED) dimension of the APZ questionnaire used in research on psychedelic experiences.[5] As of 2011, exact data on the frequency of bad trips are not available.[23] Some research suggests that the risk of a bad trip on psilocybin is higher when multiple drugs are used, when the user has a history of certain mental illnesses, and when the user is not supervised by a sober person.[22]

In clinical research settings, precautions including the screening and preparation of participants, the training of the session monitors who will be present during the experience, and the selection of appropriate physical setting can minimize the likelihood of psychological distress.[24] Researchers have suggested that the presence of professional "trip sitters" (i.e., session monitors) may significantly reduce the negative experiences associated with a bad trip.[25] In most cases in which anxiety arises during a supervised psychedelic experience, reassurance from the session monitor is adequate to resolve it; however, if distress becomes intense it can be treated pharmacologically, for example with the benzodiazepine diazepam.[24]

Research shows that preparing for the psychedelic experience, as well as the set and setting of the individual and environment they will be in, can help mitigate "bad trips''.[26][27] Harvard Psychologist Timothy Leary has said that "set" and "setting" are important to the experience.[26][27][28] Set refers to the participants' internal state – their mental, emotional and physical state, as well as their intentions for the experience (whether they want to solve a complex problem, discover the underlying secrets of the universe, or heal from a past trauma) – the better these preliminary conditions, the better the experience usually goes.[26][27] Setting refers to the environment the experience will take place in. Leary and others have found that, due to the highly suggestible nature of the psychedelic experience, the environment the participant is in plays a critical role.[26][27][29] For example, a warmly decorated room with a comfortable couch, nice music and an overall welcoming atmosphere will have a much more positive effect than a cold stainless steel and concrete reinforced hospital room.[26][27] Taking these necessary precautions before a psychedelic experience, along with the presence of trained professionals, have been shown to significantly reduce an overall negative experience.[26][27]

The psychiatrist Stanislav Grof wrote that unpleasant psychedelic experiences are not necessarily unhealthy or undesirable, arguing that they may have potential for psychological healing and lead to breakthrough and resolution of unresolved psychic issues.[30][page needed] Drawing on narrative theory, the authors of a 2021 study of 50 users of psychedelics found that many described bad trips as having been sources of insight or even turning points in life.[25]

Scientific models

[edit]

Link R. Swanson divides scientific frameworks for understanding psychedelic experiences into two waves. In the first wave, encompassing nineteenth- and twentieth-century frameworks, he includes model psychosis theory (the psychotomimetic paradigm), filtration theory, and psychoanalytic theory.[6] In the second wave of theories, encompassing twenty-first-century frameworks, Swanson includes entropic brain theory, integrated information theory, and predictive processing.[6]

Model psychosis theory

[edit]

Researchers studying mescaline in the early twentieth century and LSD in the mid-twentieth century took interest in these drugs as producing a temporary "model psychosis" that could assist researchers and medical students in understanding the experiences of patients with schizophrenia and other psychotic disorders.[31]

Filtration theory

[edit]

Aldous Huxley and Humphrey Osmond applied the pre-existing ideas of filtration theory, which held that the brain filters what enters into consciousness, to explain psychedelic experiences (and it is from this paradigm that the term psychedelic is derived).[6] Huxley believed that the brain was filtering reality itself and that psychedelics granted conscious access to "Mind at Large," whereas Osmond believed that the brain was filtering aspects of the mind out of consciousness.[6] Swanson writes that Osmond's view seems "less radical, more compatible with materialist science, and less epistemically and ontologically committed" than Huxley's.[6] Supporting this theory, research has found that LSD disrupts thalamic gating, leading to altered perceptions by allowing more information to flow through the brain's gatekeeping mechanisms.[32]

Psychoanalytic theory

[edit]

Psychoanalytic theory was the predominant interpretive framework in mid-twentieth-century psychedelic-assisted psychotherapy.[6] For instance, Czech psychiatrist Stanislav Grof characterised psychedelic experiencing as "non-specific amplification of unconscious mental processes", and he analysed the phenomenology of the LSD experience (particularly the experience of what he termed psychospiritual death and rebirth) in terms of Otto Rank's theory of the unresolved memory of the primal birth trauma.[33]

Entropic brain theory

[edit]

Entropic brain theory is a theory of consciousness proposed in 2014 by neuroscientist Robin Carhart-Harris and colleagues that was inspired by research on psychedelic drugs.[34] The theory suggests that the entropy of brain activity within certain limits indexes the richness of conscious states, particularly under the influence of psychedelics. This theory posits that elevated brain entropy correlates with heightened informational richness, suggesting that psychedelics increase brain criticality, making it more sensitive to internal and external perturbations.[35] This enhanced state of brain activity is proposed to influence susceptibility to environmental factors ("set" and "setting") and potentially offer new insights for treating psychiatric and neurological disorders, including depression and disorders of consciousness.

Integrated information theory

[edit]

Integrated information theory is a theory of consciousness proposing to explain all forms of consciousness, and has been applied specifically to psychedelic experiences by Andrew Gallimore.[36]

Predictive processing

[edit]

Sarit Pink-Hashkes and colleagues have applied the predictive processing paradigm in neuroscience to psychedelic experiences in order to formalize the idea of the entropic brain.[37]

In religious and spiritual contexts

[edit]

Alan Watts likened psychedelic experiencing to the transformations of consciousness that are undertaken in Taoism and Zen, which he says is, "more like the correction of faulty perception or the curing of a disease… not an acquisitive process of learning more and more facts or greater and greater skills, but rather an unlearning of wrong habits and opinions."[38] Watts further described the LSD experience as, "revelations of the secret workings of the brain, of the associative and patterning processes, the ordering systems which carry out all our sensing and thinking."[39]

According to Luis Luna, psychedelic experiences have a distinctly gnosis-like quality; it is a learning experience that elevates consciousness and makes a profound contribution to personal development. For this reason, the plant sources of some psychedelic drugs such as ayahuasca and mescaline-containing cacti are sometimes referred to as "plant teachers" by those using those drugs.[40]

Furthermore, psychedelic drugs have a history of religious use across the world that extends back for hundreds or perhaps thousands of years.[41] They are often called entheogens because of the kinds of experiences they can induce,[42] however various entheogens happen to also be hypnotics (muscimol mushrooms), deliriants (jimsonweed) or atypical/quasi-psychedelics like cannabis. Some small contemporary religious movements base their religious activities and beliefs around psychedelic experiences, such as Santo Daime[43] and the Native American Church.[44]

See also

[edit]

References

[edit]
  1. ^ "LSD | Michigan Medicine".
  2. ^ Tanne, Janice Hopkins (2004). "Humphrey Osmond". BMJ. 328 (7441): 713. doi:10.1136/bmj.328.7441.713. PMC 381240.
  3. ^ A. Weil, W. Rosen. (1993), From Chocolate To Morphine: Everything You Need To Know About Mind-Altering Drugs. New York, Houghton Mifflin Company. p. 93
  4. ^ Lee, Martin A. (1985). Acid Dreams: The Complete Social History of LSD: The CIA, The Sixties, and Beyond. Grove Press. p. 39. ISBN 0-802-13062-3.
  5. ^ a b c d e f Preller, Katrin H.; Vollenweider, Franz X. (2016). "Phenomenology, Structure, and Dynamic of Psychedelic States". In Adam L. Halberstadt; Franz X. Vollenweider; David E. Nichols (eds.). Behavioral Neurobiology of Psychedelic Drugs. Vol. 36. Berlin, Heidelberg: Springer Berlin Heidelberg. pp. 221–256. doi:10.1007/7854_2016_459. ISBN 978-3-662-55878-2. PMID 28025814. {{cite book}}: |journal= ignored (help)
  6. ^ a b c d e f g h i j Swanson, Link R. (2018-03-02). "Unifying Theories of Psychedelic Drug Effects". Frontiers in Pharmacology. 9: 172. doi:10.3389/fphar.2018.00172. ISSN 1663-9812. PMC 5853825. PMID 29568270.
  7. ^ R. R. Griffiths; W. A. Richards; U. McCann; R. Jesse (7 July 2006). "Psilocybin can occasion mystical-type experiences having substantial and sustained personal meaning and spiritual significance". Psychopharmacology. 187 (3): 268–283. doi:10.1007/s00213-006-0457-5. PMID 16826400. S2CID 7845214.
  8. ^ Barrett, Frederick S.; Johnson, Matthew W.; Griffiths, Roland R. (2015). "Validation of the revised Mystical Experience Questionnaire in experimental sessions with psilocybin". Journal of Psychopharmacology. 29 (11): 1182–1190. doi:10.1177/0269881115609019. PMC 5203697. PMID 26442957.
  9. ^ Barsuglia, Joseph; Davis, Alan K.; Palmer, Robert; Lancelotta, Rafael; Windham-Herman, Austin-Marley; Peterson, Kristel; Polanco, Martin; Grant, Robert; Griffiths, Roland R. (2018). "Intensity of Mystical Experiences Occasioned by 5-MeO-DMT and Comparison With a Prior Psilocybin Study". Frontiers in Psychology. 9: 2459. doi:10.3389/fpsyg.2018.02459. PMC 6292276. PMID 30574112.
  10. ^ a b c d Johnson, Matthew W.; Hendricks, Peter S.; Barrett, Frederick S.; Griffiths, Roland R. (2019). "Classic psychedelics: An integrative review of epidemiology, therapeutics, mystical experience, and brain network function". Pharmacology & Therapeutics. 197: 83–102. doi:10.1016/j.pharmthera.2018.11.010. PMID 30521880. S2CID 54467870.
  11. ^ Sanders, James W.; Zijlmans, Josjan (2021). "Moving Past Mysticism in Psychedelic Science". ACS Pharmacology & Translational Science. 4 (3): 1253–1255. doi:10.1021/acsptsci.1c00097. PMC 8205234. PMID 34151217.
  12. ^ Breeksema, Joost J.; van Elk, Michiel (2021). "Working with Weirdness: A Response to "Moving Past Mysticism in Psychedelic Science"". ACS Pharmacology & Translational Science. 4 (4): 1471–1474. doi:10.1021/acsptsci.1c00149. PMC 8369678. PMID 34423279.
  13. ^ Jylkkä, Jussi (2021). "Reconciling Mystical Experiences with Naturalistic Psychedelic Science: Reply to Sanders and Zijlmans". ACS Pharmacology & Translational Science. 4 (4): 1468–1470. doi:10.1021/acsptsci.1c00137. PMC 8369668. PMID 34423278.
  14. ^ MacLean, Katherine A.; Johnson, Matthew W.; Griffiths, Roland R. (2011). "Mystical experiences occasioned by the hallucinogen psilocybin lead to increases in the personality domain of openness". Journal of Psychopharmacology. 25 (11): 1453–1461. doi:10.1177/0269881111420188. PMC 3537171. PMID 21956378.
  15. ^ Millière, Raphaël; Carhart-Harris, Robin L.; Roseman, Leor; Trautwein, Fynn-Mathis; Berkovich-Ohana, Aviva (2018). "Psychedelics, Meditation, and Self-Consciousness". Frontiers in Psychology. 9: 1475. doi:10.3389/fpsyg.2018.01475. PMC 6137697. PMID 30245648.
  16. ^ Timmermann, Christopher; Roseman, Leor; Williams, Luke; Erritzoe, David; Martial, Charlotte; Cassol, Héléna; Laureys, Steven; Nutt, David; Carhart-Harris, Robin (2018). "DMT Models the Near-Death Experience". Frontiers in Psychology. 9: 1424. doi:10.3389/fpsyg.2018.01424. PMC 6107838. PMID 30174629.
  17. ^ Letheby, Chris; Gerrans, Philip (2017). "Self unbound: ego dissolution in psychedelic experience". Neuroscience of Consciousness. 3 (1): nix016. doi:10.1093/nc/nix016. PMC 6007152. PMID 30042848.
  18. ^ Mason, N. L.; Kuypers, K. P. C.; Müller, F.; Reckweg, J.; Tse, D. H. Y.; Toennes, S. W.; Hutten, N. R. P. W.; Jansen, J. F. A.; Stiers, P.; Feilding, A.; Ramaekers, J. G. (2020). "Me, myself, bye: regional alterations in glutamate and the experience of ego dissolution with psilocybin". Neuropsychopharmacology. 45 (12): 2003–2011. doi:10.1038/s41386-020-0718-8. PMC 7547711. PMID 32446245.
  19. ^ Nour, Matthew M.; Evans, Lisa; Nutt, David; Carhart-Harris, Robin L. (2016). "Ego-Dissolution and Psychedelics: Validation of the Ego-Dissolution Inventory (EDI)". Frontiers in Human Neuroscience. 10: 269. doi:10.3389/fnhum.2016.00269. PMC 4906025. PMID 27378878.
  20. ^ Shanon, Benny (2002). The antipodes of the mind : charting the phenomenology of the Ayahuasca experience (Reprinted ed.). New York: Oxford University Press. p. 205. ISBN 978-0-19-925292-3.
  21. ^ Bennett, Stanislav Grof with Hal Zina (2006). The holotropic mind : the three levels of human consciousness and how they shape our lives (1st paperback ed., [Nachdr.] ed.). San Francisco, Calif.: HarperSanFrancisco. p. 38. ISBN 9780062506597.
  22. ^ a b Roberts, Carl A.; Osborne-Miller, Isaac; Cole, Jon; Gage, Suzanne H.; Christiansen, Paul (2020). "Perceived harm, motivations for use and subjective experiences of recreational psychedelic 'magic' mushroom use". Journal of Psychopharmacology. 34 (9): 999–1007. doi:10.1177/0269881120936508. PMID 32674668. S2CID 220607863.
  23. ^ a b van Amsterdam, Jan; Opperhuizen, Antoon; van den Brink, Wim (2011). "Harm potential of magic mushroom use: A review". Regulatory Toxicology and Pharmacology. 59 (3): 423–429. doi:10.1016/j.yrtph.2011.01.006. PMID 21256914.
  24. ^ a b Johnson, Matthew W.; Richards, William A.; Griffiths, Roland R. (2008). "Human Hallucinogen Research: Guidelines for Safety". Journal of Psychopharmacology. 22 (6): 603–620. doi:10.1177/0269881108093587. PMC 3056407. PMID 18593734.
  25. ^ a b Gashi, Liridona; Sandberg, Sveinung; Pederson, Willy (2021). "Making "bad trips" good: How users of psychedelics narratively transform challenging trips into valuable experiences". International Journal of Drug Policy. 87: 102997. doi:10.1016/j.drugpo.2020.102997. hdl:10852/81144. PMID 33080454. S2CID 224821288.
  26. ^ a b c d e f Fadiman, James (2011). The psychedelic explorer's guide: safe, therapeutic, and sacred journeys. Rochester, Vt: Park Street Press. ISBN 978-1-59477-402-7.
  27. ^ a b c d e f Pollan, Michael (2018). How to change your mind. New York: Penguin Press. ISBN 978-1-59420-422-7.
  28. ^ Waldman, Ayelet (2017). A Really Good Day (1st ed.). Knopf.
  29. ^ Hofmann, Albert (2017). LSD My Problem Child: Reflections on Sacred Drugs, Mysticism and Science (4th ed.). Multidisciplinary Association for Psychedelic Studies.
  30. ^ Stanislav Grof, LSD Psychotherapy
  31. ^ Aday, Jacob S.; Bloesch, Emily K.; Davoli, Christopher C. (2019). "Beyond LSD: A Broader Psychedelic Zeitgeist during the Early to Mid-20th Century". Journal of Psychoactive Drugs. 51 (3): 210–217. doi:10.1080/02791072.2019.1581961. PMID 30836890. S2CID 73466221.
  32. ^ Dolan, Eric W. (2023-06-02). "Neuroscience research sheds light on how LSD alters the brain's "gatekeeper"". PsyPost - Psychology News. Retrieved 2024-02-14.
  33. ^ Grof, Stanislav (1976). Realms of the human unconscious : observations from LSD research. New York: Dutton. p. 98. ISBN 0-525-47438-2.
  34. ^ Carhart-Harris, Robin; Leech, Robert; Hellyer, Peter J.; Shanahan, Murray; Feilding, Amanda; Tagliazucchi, Enzo; Chialvo, Dante R.; Nutt, David (2014). "The entropic brain: a theory of conscious states informed by neuroimaging research with psychedelic drugs". Frontiers in Human Neuroscience. 8: 20. doi:10.3389/fnhum.2014.00020. PMC 3909994. PMID 24550805.
  35. ^ Carhart-Harris, Robin L. (2018-11-01). "The entropic brain - revisited". Neuropharmacology. Psychedelics: New Doors, Altered Perceptions. 142: 167–178. doi:10.1016/j.neuropharm.2018.03.010. ISSN 0028-3908.
  36. ^ Gallimore, Andrew R. (2015). "Restructuring consciousness –the psychedelic state in light of integrated information theory". Frontiers in Human Neuroscience. 9: 346. doi:10.3389/fnhum.2015.00346. PMC 4464176. PMID 26124719.
  37. ^ Pink-Hashkes, Sarit; van Rooij, Iris; Kwisthout, Johan (2017). Perception is in the Details: A Predictive Coding Account of the Psychedelic Phenomenon (PDF). The 39th Annual Meeting of the Cognitive Science Society.
  38. ^ Watts, Alan W. (2013). The Joyous Cosmology: Adventures in the Chemistry of Consciousness (Second ed.). New World Library. p. 15. ISBN 9781608682041.
  39. ^ Watts, Alan W. (2013). The Joyous Cosmology: Adventures in the Chemistry of Consciousness (Second ed.). New World Library. p. 44. ISBN 9781608682041.
  40. ^ Luna, Luis Eduardo (1984). "The concept of plants as teachers among four mestizo shamans of Iquitos, northeastern Peru" (PDF). Journal of Ethnopharmacology. 11 (2): 135–156. doi:10.1016/0378-8741(84)90036-9. PMID 6492831. Retrieved 10 July 2020.
  41. ^ Griffiths, R. R.; Richards, W. A.; Johnson, M. W.; McCann, U. D.; Jesse, R. (2008). "Mystical-type experiences occasioned by psilocybin mediate the attribution of personal meaning and spiritual significance 14 months later". Journal of Psychopharmacology. 22 (6): 621–632. doi:10.1177/0269881108094300. ISSN 0269-8811. PMC 3050654. PMID 18593735.
  42. ^ Rätsch, Richard Evans Schultes, Albert Hofmann, Christian (2001). Plants of the gods : their sacred, healing, and hallucinogenic powers (Rev. and expanded ed.). Rochester, Vt.: Healing Arts Press. ISBN 0892819790.{{cite book}}: CS1 maint: multiple names: authors list (link)
  43. ^ Santos, R. G.; Landeira-Fernandez, J.; Strassman, R. J.; Motta, V.; Cruz, A. P. M. (2007). "Effects of ayahuasca on psychometric measures of anxiety, panic-like and hopelessness in Santo Daime members". Journal of Ethnopharmacology. 112 (3): 507–513. doi:10.1016/j.jep.2007.04.012. PMID 17532158.
  44. ^ Calabrese, Joseph D. (1997). "Spiritual healing and human development in the Native American church: Toward a cultural psychiatry of peyote". Psychoanalytic Review. 84 (2): 237–255. PMID 9211587.

Further reading

[edit]
  • Grinspoon, Lester; Bakalar, James. B., eds. (1983). Psychedelic Reflections. New York: Human Sciences Press. pp. 13–14. ISBN 0-89885-129-7.
  • Halberstadt, Adam L.; Franz X. Vollenweider; David E. Nichols, eds. (2018). Behavioral Neurobiology of Psychedelic Drugs. Current Topics in Behavioral Neurosciences. Vol. 36. Berlin, Heidelberg: Springer. ISBN 978-3-662-55878-2.
  • Letheby, Chris (2021). Philosophy of Psychedelics. Oxford: Oxford University Press. doi:10.1093/med/9780198843122.001.0001. ISBN 978-0-19-884312-2.
  • Richards, William A. (2016). Sacred Knowledge: Psychedelics and Religious Experiences. New York: Columbia University Press. ISBN 978-0-231-54091-9.