Saturday, August 11, 2012

Neurobiology of Wisdom - A Literature Overview

This is an article from the April 2009 issue of JAMA's Archives of General Psychiatry - it's one of the rare open source articles published by JAMA.

Wisdom is an idea we talk about a lot - and I am sure most of us would like to feel we have more of it than we currently do. But what is wisdom? Is there an accepted definition that we can then create an assessment to measure for in others?

The authors do offer a collection of traits associated with wisdom in this slide:

It's an interesting article - and it can be downloaded as a PDF.

Neurobiology of Wisdom: A Literature Overview 

Thomas W. Meeks, MD and Dilip V. Jeste, MD
Arch Gen Psychiatry. 2009;66(4):355-365.
Original Article |


Context  Wisdom is a unique psychological trait noted since antiquity, long discussed in humanities disciplines, recently operationalized by psychology and sociology researchers, but largely unexamined in psychiatry or biology.

Objective  To discuss recent neurobiological studies related to subcomponents of wisdom identified from several published definitions/descriptions of wisdom by clinical investigators in the field, ie, prosocial attitudes/behaviors, social decision making/pragmatic knowledge of life, emotional homeostasis, reflection/self-understanding, value relativism/tolerance, and acknowledgment of and dealing effectively with uncertainty.

Data Sources  Literature focusing primarily on neuroimaging/brain localization and secondarily on neurotransmitters, including their genetic determinants.

Study Selection  Studies involving functional neuroimaging or neurotransmitter functioning, examining human (rather than animal) subjects, and identified via a PubMed search using keywords from any of the 6 proposed subcomponents of wisdom were included.

Data Extraction  Studies were reviewed by both of us, and data considered to be potentially relevant to the neurobiology of wisdom were extracted.

Data Synthesis  Functional neuroimaging permits exploration of neural correlates of complex psychological attributes such as those proposed to comprise wisdom. The prefrontal cortex figures prominently in several wisdom subcomponents (eg, emotional regulation, decision making, value relativism), primarily via top-down regulation of limbic and striatal regions. The lateral prefrontal cortex facilitates calculated, reason-based decision making, whereas the medial prefrontal cortex is implicated in emotional valence and prosocial attitudes/behaviors. Reward neurocircuitry (ventral striatum, nucleus accumbens) also appears important for promoting prosocial attitudes/behaviors. Monoaminergic activity (especially dopaminergic and serotonergic), influenced by several genetic polymorphisms, is critical to certain subcomponents of wisdom such as emotional regulation (including impulse control), decision making, and prosocial behaviors.

Conclusions  We have proposed a speculative model of the neurobiology of wisdom involving frontostriatal and frontolimbic circuits and monoaminergic pathways. Wisdom may involve optimal balance between functions of phylogenetically more primitive brain regions (limbic system) and newer ones (prefrontal cortex). Limitations of the putative model are stressed. It is hoped that this review will stimulate further research in characterization, assessment, neurobiology, and interventions related to wisdom.
Here is an interesting section from the discussion that offers a series of ideas for future research on this topic.

Our suggested model of the neurobiology of wisdom raises a conceptual issue. How can our holistic concept of wisdom as a distinct trait, which is consistent with the unified theory of mind,130 be compatible with the reductionism implicit in the relationship between individual brain regions and specific mental functions hypothesized in the neuroimaging research reviewed earlier? We believe that these 2 perspectives can coexist, just as Takahashi and Overton5 have sought to integrate the analytic and synthetic models of wisdom. Examining functional divisions in the brain via fMRI and similar methods is potentially valuable. For example, Jung and Haier131 recently reviewed neuroimaging studies relevant to human intelligence and reasoning. They concluded that there are several distinct brain regions that contribute to intelligence and reasoning and that the coordination among these regions appears to follow a pattern they termed parieto-frontal integration. As expected, there is partial overlap in the brain regions (eg, ACC, DLPFC) implicated in their review and ours. Nonetheless, there are several important characteristics in which wisdom differs from intelligence and reasoning in that it also includes domains such as practical application of knowledge, use of knowledge for the common social good, and integration of affect and knowledge.12 ,132 Brain regions putatively involved in wisdom that were not prominent in the review of intelligence and reasoning131 include limbic cortex, MPFC, and striatum. Although there is general agreement regarding important functional divisions within the brain, the nature of these divisions is almost assuredly oversimplified and will undergo continual revisions.5 The same would apply to specific subcomponents of wisdom.

The possible neurochemical and genetic contributions to wisdom (Table 1) are related to many of those identified in psychopathology. The fact that monoaminergic functioning is related to stress reactivity and emotional homeostasis is not surprising. The possible roles of oxytocin and vasopressin in prosocial behaviors demonstrate the importance of examining nontraditional neurotransmitters.

Empirical research on wisdom is in its infancy. There are several potentially valuable lines of research that may be suggested.

  • Defining a valid phenotype: Reliability and validity of theory-based definitions of wisdom should be demonstrated across different populations.
  • Objectively measuring wisdom: Relatively objective, reliable measures of real-world behaviors should be developed.
  • Investigating developmental course of wisdom: Wisdom may be studied from a developmental perspective to identify possible critical periods for wisdom development. Advances in genetics/genomics and connectivity analyses in functional neuroimaging as well as electrophysiology may help clarify the interplay between biological and environmental factors in the lifetime course of wisdom.
  • Examining relationship of wisdom to sociodemographic variables: Older age has been traditionally associated with wisdom but the limited available empirical research does not consistently support this notion.133 135 The neurobiological literature is sparse regarding age-related differences in most of the subcomponents of wisdom discussed. One notable exception is that aging has been associated with better emotional regulation.136 The possible enhancement of wisdom and its specific subcomponents with aging-related cumulative life experience warrants investigation. Cross-cultural comparisons of wisdom and sex differences also deserve research.
  • Studying neuropsychiatric disorders affecting wisdom: Research in naturally occurring disorders (eg, frontotemporal dementia137 or traumatic injuries [eg, case of Phineas Gage])138 that affect the implicated neurobiological substrates of wisdom would help inform the neurobiology of wisdom as well as clinical applications of the concept.
  • Using animal models: While wisdom may be uniquely human, certain intermediate phenotypes could be studied in appropriate animal models.
  • Assessing health care implications of wisdom: Research on possible impact of wisdom on longevity, quality of life, and receipt of improved health care would have major public health significance.
  • Developing interventions to enhance wisdom: Development and testing of interventions (psychosocial or biological) to enhance wisdom could be valuable for people with and without serious psychopathology. Similarly, whether wisdom moderates the outcomes of other interventions (eg, psychotherapy) would be useful to evaluate.

Wisdom warrants scientific study with the same rigorous methods that we demand in investigations on various forms of psychopathology. At the same time, progress in such research will require maintaining the wisdom to recognize the limits of available scientific methods.

BBC - Fear and Loathing on the Road to Hollywood: A Portrait of Hunter S. Thompson

Open Culture has posted this 1978 documentary from the BBC on Hunter S. Thompson, who even by then had lost himself in the myth of himself. It's revealing and interesting.

Fear and Loathing on the Road to Hollywood: The BBC’s 1978 Portrait of Hunter S. Thompson

August 10th, 2012

“It’s been four years, maybe five,” mutters artist Ralph Steadman as his flight descends into Colorado. “I don’t know what the man has done since then. He may have terrible brain damage.” He speaks of a famous collaborator, a writer whose verbal style the culture has linked forever with Steadman’s own visual style. “He has these mace guns and CO2 fire extinguishers, which he usually just aims at people,” Steadman’s voiceover continues, and we know this collaborator could be none other than Hunter S. Thompson, the impulsive, drug- and firearm-loving chronicler of an American Dream gone sour.  Many of Steadman’s fans no doubt found their way into his blotchy and grotesque but nevertheless precisely observed artistic world in the pages of Thompson’s best-known book, 1971′s Fear and Loathing in Las Vegas — or in those of its follow-up Fear and Loathing on the Campaign Trail ’72, or alongside his “gonzo” ground-breaking article “The Kentucky Derby is Decadent and Depraved.” Fear and Loathing on the Road to Hollywood, the BBC Omnibus documentary above, finds the men reuniting in 1978 to take a journey into the heart of, if not the American Dream, then at least the ostensible American “Dream Factory.”

As Steadman’s British, middle-aged stolidness may seem surprising given the out-and-out insanity some see in his imagery, so Thompson’s famously erratic behavior belies his words’ sober (as it were) indictment of America. He wrote of Thomas Jefferson’s belief in America as “a chance to start again [ .. ] a fantastic monument to all the best instincts of the human race.” But alas, “instead, we just moved in here and destroyed the place from coast to coast like killer snails.” We see him cruise the Vegas strip, suffer a fit of paranoia by Grauman’s Chinese Theater (though I myself react similarly to Hollywood Boulevard), and take a meeting about the film that may or may not have become Where the Buffalo Roam, which featured Bill Murray in the Thompsonian persona. We see archival footage of Murray helping Thompson out with his sardonic “Re-elect Nixon in 1980″ campaign. We even see Thompson have a hotel-room sit-down with Nixon’s White House Counsel John Dean, who testified against the President in the Watergate trial. Between these segments, Thompson reflects on the wild, substance-fueled persona he created, and how it had gotten away from him even then: “I’m really in the way, as a person. The myth has taken over.” But he always had an eye on the next phase: at the documentary’s end, he draws up plans for the memorial mount and cannon that would, 27 years later, fire his ashes high into the air.

[NOTE: Fear and Loathing on the Road to Hollywood's narrator refers to Thompson as a former Hell's Angel. In fact, he only rode alongside the Hell's Angels, collecting material for the book Hell's Angels: The Strange and Terrible Saga of the Outlaw Motorcycle Gangs. Remaining a non-member all the while, he even bought a British bike to distinguish himself from the Harley-Davidson-dedicated gang.]

Look for Fear and Loathing on the Road to Hollywood in our collection of Free Movies Online, under Documentaries.

Related Content:
Colin Marshall hosts and produces Notebook on Cities and Culture. Follow him on Twitter at @colinmarshall.

Romney Chooses Ryan - Ends All Pretense of Empthy for the Not Wealthy

Mitt Romney's biggest challenge in the presidential campaign for so far has been likeability - he comes across as cold, insincere (look at the fake smile above), and disconnected from the harsh reality with which most Americans live. Many commentators have referred to it as the empathy gap.

With his announcement Friday night of congressman Paul Ryan (WI) as his Vice-Presidential running mate, Romney has given up on empathy it would seem, preferring instead to gamble that his wealthy backers will support his choice with enough Super PAC money to generate a barrage of misinformation that will scare Americans into fearing Obama enough to choose the white capitalists over the black "socialist."

As a progressive who values compassion as a political stance (and I am not a Democrat), I see this is almost the perfect pick to guarantee Obama's re-election. I have a lot of issues with Obama (his health care plan sold out the middle class to provide coverage to the poorest Americans; his use of drone attacks is not only illegal but morally problematic; his leadership style is to focused on consensus and not enough on getting the best legislation; the list could go on and on), but his understanding of how most of America is struggling is not one of those problems.

Obama's work as a community organizer put him at the center of poverty in large cities, giving him an understanding that Romney lacks completely. Obama values the one-on-one connection with individuals that seems to make Romney uncomfortable.

So what does Romney do to combat these challenges? He chooses Paul Ryan, the most divisive high-profile Republican congressman in the country, a man who is beloved by the racist Tea Party crowd, who is owned by Big Oil, who is vehemently opposed to gay marriage (or even gay rights), who is a virulent denier of climate science (and all other forms of science), who has one of the worst environmental voting records in the House, and worst of all, is pushing a budget plan that escalates tax cuts for the wealthy whilemassively cutting government programs such as social security, medicare, medicaid, food stamps, student loans and other social programs.

Response from the Left has been what one would expect:

Think Progress: Meet Paul Ryan: Climate Denier, Conspiracy Theorist, Koch Acolyte
Mother Jones: With Paul Ryan, Romney Makes the VP Pick Obama Wanted
The Daily Beast: Romney-Ryan: The Rich Voter's Dream Ticket
Daily Kos: Introducing the Committee to End Medicare: Romney-Ryan 2012

The Right seems to be pleased to have a man Romney describes as a “person of great steadiness” and someone who “combines a profound sense of responsibility…with unbounded optimism,” and as the “intellectual leader of the Republican party.”

Obama's campaign team must be doing the "Happy, Happy, Joy, Joy" Dance.

Friday, August 10, 2012

Personality, Psychopathology, Life Attitudes and Neuropsychological Performance among Ritual Users of Ayahuasca: A Longitudinal Study

As far as I know, this is the first longitudinal study on the use of ayahuasca, the Amazonian entheogenic mixture that (after the purging, which is an important element of the experience), offers one of the more intense and spiritual hallucinogenic experiences recorded. It is also one of the most healing experiences, especially for addictions according to Gabor Maté.

This study shows, convincingly, that ayahuasca users are well-adjusted, lacking in psychopathology, and more spiritual (higher self-transcendence scores) than the control group.

Before presenting the new study, here is a little background on ayahuasca.

An Introduction to Ayahuasca

Ayahuasca (aya-spirit/dead, waska-vine/rope) or Yage (ya-hey) are native Amazonian names for the jungle vine Banisteriopsis Caapi, and the medicinal tea prepared from it. Ayahuasca is used throughout the Upper Amazon to enable access to the visionary or mythological world that provides revelation, blessing, healing, and ontological solace (Dobkin de Rios 1972, Grof 1994, Andritsky 1984).

The Banisteriopsis caapi vine is a Malpighiaceous jungle liana found in the tropical regions of Peru, Bolivia, Panama, Brazil, the Orinoco of Venezuela and the Pacific Coast of Colombia/Ecuador. The vine is the common base ingredient of the Ayahuasca tea. B. caapi contains beta-carbolines that exhibit sedative, hypnotic, anti-depressant, monoamine oxidase inhibiting, and threshold visionary activity.

Ayahuasca is a synergystic potion. A wide variety of admixture plants is used by the indigenous tribes of the Upper Amazon. Vine-only brew is sometimes used. Most typically the vine is mixed with a tryptamine carrying plant. The foliage of Psychotria viridis (Chacruna) is the principal admixture of Ayahuasca potions employed throughout Peru and Brazil. In Columbia and Amazonian Ecuador, the plant Diplopterys cabrerana (Chaliponga) is often used instead.

These plants provide the “light” or the visionary qualities, but these tryptamine-containing plants are not orally active alone. The monoamine oxidase inhibiting action of the B. caapi vine makes it possible for the tryptamines to produce powerful visions. In turn, the admixture plants potentiate the Vine.

The combination of the Caapi vine with Chacruna or Chaliponga is sometimes known as a marriage of Power and Light. This marriage unlocks the full shamanic mareacion and its visionary mythological vistas.

This medicine has been used for millennia in order to enter the sacred supernatural world, to heal, divine, and worship.

The use of Ayahuasca may well be primordial, its use extending back to the earliest aboriginal inhabitants of the Upper Amazon region. Abstract liminal patterns such as zigzags, serrated lines and geometric forms found on ancient relics and traditional textiles, pottery and body art of various tribes represent the perceptual threshold between everyday and transpersonal realms of consciousness. These relics, combined with an abundance of myths describing the origin of Ayahuasca as deeply intertwined cosmologically with the creation of the universe, earth, and tribal people, indicate a long history of human use.

Ayahuasca is a revered and respected sacred medicine, considered a spiritual and physiological panacea par excellence, because its medicine can instruct in healing, visionary insight, and the art of using plants for various purposes. Sometimes it is referred to simply as La Medicina – the Medicine.

For indigenous people such as the Napo Runa of Ecuador, Ayahuasca is “the mother of all medicines” and “the mother of all plants.” Other peoples regard Ayahuasca as a Grandfather or Grandmother. Ayahuasca, “the Vine with a soul,” is perceived as a communicating being who guides, teaches, and heals. Ayahuasca also acts as a mediator and translator between the human and plant worlds, and teaches humans how to communicate with plants and use them for various purposes.

There's more to read if interested . . .

With that background, here is the new research article . . . that offers very interesting and positive evaluations of ritual users of ayahuasca.

Personality, Psychopathology, Life Attitudes and Neuropsychological Performance among Ritual Users of Ayahuasca: A Longitudinal Study

José Carlos Bouso1,2,3*, Débora González4, Sabela Fondevila5, Marta Cutchet6, Xavier Fernández7, Paulo César Ribeiro Barbosa8, Miguel Ángel Alcázar-Córcoles9, Wladimyr Sena Araújo10, Manel J. Barbanoj2, Josep Maria Fábregas6, Jordi Riba1,2,11

1 Human Experimental Neuropsychopharmacology. IIB Sant Pau, Barcelona, Spain, 2 Centre d’Investigació de Medicaments. Servei de Farmacologia Clínica, Departament de Farmacologia i Terapèutica, Universitat Autònoma de Barcelona. Hospital de la Santa Creu i Sant Pau, Barcelona, Spain, 3 International Center for Ethnobotanical Education, Research and Service, ICEERS, Halsteren, Netherlands, 4 Unidad Farmacología Humana y Neurociencias, Instituto de Investigación Hospital del Mar-IMIM, Parc de Salut Mar, Universidad Autónoma de Barcelona, Barcelona, Spain, 5 Center UCM-ISCIII for Human Evolution and Behavior, Madrid, Spain, 6 Instituto de Etnopsicología Amazónica Aplicada (IDEAA), Barcelona, Spain, 7 Independent Researcher, Barcelona, Spain, 8 Departamento de Filosofia e Ciências Humanas, Universidade Estadual de Santa Cruz (UESC), Ilhéus, Bahia, Brazil, 9 Departamento de Psicología Biológica y de la Salud, Facultad de Psicología, Universidad Autónoma de Madrid (UAM). Cantoblanco, Madrid, Spain, 10 Prefeitura Municipal de Rio Branco, Conselho Estadual de Educação do Estado do Acre, Rio Branco, Acre, Brazil, 11 Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, Barcelona, Spain


Ayahuasca is an Amazonian psychoactive plant beverage containing the serotonergic 5-HT2A agonist N,N-dimethyltryptamine (DMT) and monoamine oxidase-inhibiting alkaloids (harmine, harmaline and tetrahydroharmine) that render it orally active. Ayahuasca ingestion is a central feature in several Brazilian syncretic churches that have expanded their activities to urban Brazil, Europe and North America. Members of these groups typically ingest ayahuasca at least twice per month. Prior research has shown that acute ayahuasca increases blood flow in prefrontal and temporal brain regions and that it elicits intense modifications in thought processes, perception and emotion. However, regular ayahuasca use does not seem to induce the pattern of addiction-related problems that characterize drugs of abuse. To study the impact of repeated ayahuasca use on general psychological well-being, mental health and cognition, here we assessed personality, psychopathology, life attitudes and neuropsychological performance in regular ayahuasca users (n = 127) and controls (n = 115) at baseline and 1 year later. Controls were actively participating in non-ayahuasca religions. Users showed higher Reward Dependence and Self-Transcendence and lower Harm Avoidance and Self-Directedness. They scored significantly lower on all psychopathology measures, showed better performance on the Stroop test, the Wisconsin Card Sorting Test and the Letter-Number Sequencing task from the WAIS-III, and better scores on the Frontal Systems Behavior Scale. Analysis of life attitudes showed higher scores on the Spiritual Orientation Inventory, the Purpose in Life Test and the Psychosocial Well-Being test. Despite the lower number of participants available at follow-up, overall differences with controls were maintained one year later. In conclusion, we found no evidence of psychological maladjustment, mental health deterioration or cognitive impairment in the ayahuasca-using group.

Citation: Bouso JC, González D, Fondevila S, Cutchet M, Fernández X, et al. (2012). Personality, Psychopathology, Life Attitudes and Neuropsychological Performance among Ritual Users of Ayahuasca: A Longitudinal Study. PLoS ONE 7(8): e42421. doi:10.1371/journal.pone.0042421

Do be sure to read the whole article, but I want to skip directly to the Discussion. The researchers looked at personality, psychopathology, neuropsychological functions, and  life attitude and psychosocial well-being. In all realms, ayahuasca users scored higher than controls.


In this paper we present data from a field research study in which personality, mental health, life attitudes and neuropsychological performance were assessed in a large number of ritual ayahuasca users and their matched controls.

1. Personality

The TCI [49] was used to assess personality. Differences between ayahuasca users and controls were found in several of the temperament dimensions, which are believed to be genetically determined. Higher scores on Reward Dependence (RD) may reflect a feature allowing the group to adapt to a demanding environment such as the tropical rainforest. This interpretation is supported by the significant scores on the RD subdimensions Attachment (RD3) and Dependence (RD4), but not Sentimentality (RD1). This profile is probably useful for life in a small community and in a hostile ecological environment. Participants in the Jungle sample showed a trend to higher scores on Persistence than their urban counterparts. Higher scores on this temperament dimension could explain the adaptation capacity shown by these people to their environment, and the ability to persist as a group despite isolation. Additionally, Harm Avoidance (HA) was lower in the ayahuasca-using subjects, probably reflecting the strength in personality required to undergo regular ayahuasca sessions for long periods of time. It is interesting to note that there were no differences between groups in Novelty Seeking (NS) scores nor in its subscales, including Impulsiveness (NS2). Since high scores in NS and Impulsiveness have been associated with drug use [50], [51], the mere search for new experiences may not be the underlying reason of their involvement with ayahuasca. On the contrary, members of the ayahuasca religions report that the experiences transcend the merely perceptual or recreational aspects of psychoactive drug effects.

The analysis of Character dimensions showed that ayahuasca users scored significantly higher in Self-Transcendence (ST). Since all participants (users and controls) actively practiced some religion, and Character traits can be influenced by personal experience and culture, this finding could be interpreted as a direct effect of ayahuasca use. Self-Directedness (SD), another Character dimension, is consistently lower in the ayahuasca groups, and may also be related to ayahuasca intake. Used in a religious context, the potent psychotropic effects of ayahuasca may strengthen adherence to the doctrine. The lower Self-Directedness (SD) scores found may reflect the greater relevance of the community over the individual. At the same time, there were no differences between users and controls in Cooperativeness (C). So despite greater Self-Transcendence and spirituality in the ayahuasca-using group, willingness to cooperate with others was not different from that seen in more conventional religions. It would be very interesting to assess if subjects who have decided to leave the group and discontinue ayahuasca use share personality traits with the long-term users.

In a group of 15 long term urban ayahuasca users, Grob et al. [28] found lower scores on NS and HA and no differences in RD compared to 15 matched non-users, in line with our own results. The higher RD scores in our study, driven mainly by the Jungle sample, may reflect the difference in environment mentioned above. Another research group has found changes in the Temperament dimensions of the TCI after 6 months of regular ayahuasca use in a religious setting in subjects who were initially naïve to ayahuasca. However, these same subjects did not show changes in the Character dimensions [52]. Based on these findings, a less conservative explanation for the differences observed in Temperament traits in the present study would be that they are a consequence and not the cause of ritual ayahuasca use. This would mean that ayahuasca may induce changes in personality traits traditionally considered inherited. A recent study in which high doses of psilocybin were administered in a supportive setting showed positive long term changes in Openness to Experiences [53]. This temperament trait is considered to be the most substantially heritable trait in the Big Five personality model, and relatively stable through adulthood [54].

2. Psychopathology

The analysis of psychopathology indicators showed the important finding that ayahuasca users scored significantly lower on all nine dimensions of the SCL-90-R. The two immediate explanations for this finding are that either ayahuasca has a low potential to induce psychopathology, or that samples of long-term users suffer from a self-selection bias by which only those who do not experience adverse psychological effects continue ayahuasca use. Regarding the second explanation it is worth mentioning that at follow-up lower scores were still seen on most dimensions, despite the loss in sample size. Similar findings have been reported in the literature. In a study where a group of 32 long term US ayahuasca users were assessed with the same instrument, scores were significantly lower than normative data for 7 of the 9 dimensions [31]. Halpern et al. [55] did not find evidence either of psychopathology in a group of peyote (a mescaline-containing cactus) users when compared to controls. Grob et al. [28] did not find evidence of psychopathology in their ayahuasca-taking sample using the CIDI (Composite International Diagnostic Interview), despite the fact that in the retrospective assessment most subjects met criteria for psychiatric disorders prior to their religious use of ayahuasca. Another study with teenage members of an ayahuasca church did not find differences with the control group, but rather showed a tendency to an improvement in some measures of psychopathology [30]. Barbosa et al. [52], [56] also failed to find psychophatological symptoms both in the short-term after a first ritual ayahuasca experience, and at follow up 6 months after continued use. Some participants even showed a decrease in minor psychopathological symptoms.

In summary, though there are case reports describing psychiatric complications following ayahuasca intake [24], [25], it appears that current long-term users do not show higher psychopathology. One study reported that some experienced users even show reduced scores of panic and hopelessness while under the effects of the tea [57]. Future research should assess not only long-term users but also ex-users to evaluate whether adverse psychological effects play any role in the decision to discontinue use. The apparent contradiction between reports of psychiatric crisis after acute ayahuasca and the absence of psychopathology in many chronic users should be studied in more detail.

One last consideration is the potential bias introduced by the self-assessment nature of the SCL-90-R. Subjects may have been inclined to give socially acceptable responses. However, scores on the PST subscale were always higher than 3–4. According to the interpretation norms for the SCL-90-R [58], low scores on this subscale would be indicative of a social desirability bias. Further support for the validity of our present findings is derived from results in the neuropsychological assessment (see below). Psychiatric disorders are commonly accompanied by neuropsychological deficits [59], [60], but these were not observed in the ayahuasca-using subjects in the present study.

3. Neuropsychological Functions

Based on the administered tests and the Frontal Systems Behaviour Scales, we found no evidence of neuropsychological impairment in the ayahuasca-using group. Furthermore, in general terms they scored better than their respective comparison groups and these differences were maintained one year later.

These results do not fit the hypothesis of potential frontal impairment secondary to 5-HT2A receptor activation, and are more in line with prior observations in users of psychedelics. Grob et al. [28] found no working memory deficits in their sample of ayahuasca users, but rather an improvement in one memory subset. Da Silveira et al. [29] did not find deficits in the stroop and other neuropsychological tests in their group of adolescent ritual ayahuasca users. These users did not score differently than their control group in most variables. They did fare worse on some memory subtests, but results were within the normalcy range. Halpern et al. [55] did not find neuropsychological impairment in a group of long term peyote users from the Native American Church. Tests included the Stroop test, the Wisconsin Card Sorting Test and working memory tests. Although more research is needed before definite conclusions can be drawn regarding this drug class, based on the available evidence chronic use of psychedelics does not seem to cause cognitive impairment.

The lack of cognitive impairment in our ayahuasca users can not be attributed to a lack of sensitivity of the neuropsychological tests administered, as they were sensitive enough to differentiate between users and non users. The Stroop task and the Wisconsin Card Sorting Test tap various cognitive functions such as selective attention, behavioral inhibition, working memory and goal-directed behavior, and are sensitive to PFC damage [61]. Also, these same tests have been found to detect neuropsychological impairment in various groups of drug abusers. For example, the Wisconsin Card Sorting Test has proven sensitive to detect flexibility impairments in non-addicted cocaine polydrug users (between 1–4 gr. of cocaine per month). This population showed more Perseverative Errors, fewer Categories Completed and worse Conceptual Level Responses than matched controls [62]. Also, the Stroop test was sensitive to detect executive dysfunctions in individuals using alcohol [63], cocaine [64] and amphetamines [65]. The same applies to the Letter-Number Sequencing task [66]. However, the detection of differences between users and non-users is known to be influenced by the length of the abstinence period, the severity and duration of the addiction, the use of multiple drugs and the presence of associated psychopathology [67]. In any case, better performance in the drug-using group is rarely found in the literature other than for the psychedelics. Animal research has shown that 5-HT2A receptor activation plays a role in normal neuropsychological and memory functioning [68][71]. Another explanation for the present results has to do with motivation. There is evidence that motivation may in fact improve performance of drug users in neuropsychological tasks [72]. While the recruited ayahuasca users may have been motivated to demonstrate the safety of ayahuasca to researchers, the controls did not obtain any specific benefit from their participation in the study.

Concerning the capacity of the Frontal Systems Behaviour Scales, a self-report questionnaire, to detect impairment, it is worth noting that it has revealed deficits in non-addicted [73] and addicted polydrug users [74], [75]. The lower scores found for our ayahuasca subjects on this measure of prefrontal deficits is consistent with their better neuropsychological performance. This result was found for both samples in the first assessment and in the second.

4. Life Attitude and Psychosocial Well-being

All SOI scores were consistently higher in both samples and along time for the ayahuasca users, in consonance with scores on the Self-Transcendence subscale of the TCI. Although a recent study showed no significant differences in spiritually after an ayahuasca session, the magnitude of the observed change was positively correlated with the intensity of the peak of the experience [76]. The qualitative data recorded revealed common spiritual themes among participants [76]. In our first assessment, ayahuasca users showed higher scores on Purpose in Life, although this finding was not replicated one year later. This difference in Purpose of Life may be understood as a consequence of the religious use of ayahuasca, and is compatible with adherence to a religious belief [77]. In line with the above results, ayahuasca users scored higher on subjective psychological well-being. In a previous report where these same participants were assessed on frequency and degree of illicit drug use, ayahuasca users scored lower on the different dimensions of the Addition Severity Index (ASI; [23]). Taken together, the data point at better general mental health and bio-psycho-social adaptation in the ayahuasca-using group compared to the control subjects.
For lovers of details, this one is particularly relevant - the control group was chosen due to their spiritual practices, so that the groups would be evenly matched in terms of spirituality. Despite this, the ayahuasca group score higher on the Spiritual Orientation Inventory.

The Spiritual Orientation Inventory (SOI)

In the first assessment, ayahuasca users showed significantly higher scores on all 9 components of the SOI, as revealed by a main Group effect on Transcendent Dimension [F(1,216) = 153.54; p<0.001], Meaning and Purpose in Life [F(1,216) = 78.44; p<0.001], Mission in Life [F(1,216) = 76.62; p<0.001], Sacredness of Life [F(1,216) = 30.14; p<0.001], Material Values [F(1,216) = 66.78; p<0.001], Altruism [F(1,216) = 19.32; p<0.001], Idealism [F(1,216) = 25.59; p<0.001], Awareness of the Tragic [F(1,216) = 48.64; p<0.001], and Fruits of Spirituality [F(1,216) = 91.03; p<0.001]. A significant Group by Sample interaction was found for the latter dimension [F(1,216) = 4.45; p = 0.036], with differences between users and controls being larger in the Urban sample than in the Jungle sample.

In the second assessment, the pattern of results remained unchanged, with higher scores on all components in the ayahuasca-using subjects. Thus, significant Group effects were found on Transcendent Dimension [F(1,112) = 73.68; p<0.001], Meaning and Purpose in Life [F(1,112) = 33.88; p<0.001], Mission in Life [F(1,112) = 38.56; p<0.001], Sacredness of Life [F(1,112) = 38.83; p<0.001], Material Values [F(1,112) = 21.82; p<0.001], Altruism [F(1,112) = 5.02; p = 0.027], Idealism [F(1,112) = 7.33; p = 0.008], Awareness of the Tragic [F(1,112) = 16.36; p<0.001], and Fruits of Spirituality [F(1,112) = 44.01; p<0.001].

Alva Noë on Reductionism: "The assumption is that we’re trapped inside our heads"

Philosopher Alva Noë argues that as science gets better, it needs to move beyond "certain straight-jacketing individualistic, internalistic assumptions, assumptions" - such as reductionism - that are inhibiting a broader understanding (and science) of human consciousness.

Noë argues for - and I am in total agreement - an integrated, contextualized neuroscience of consciousness, a view that incorporates the interpersonal and intersubjective embeddedness of our experience as well as the body-brain level experience of the world.

2%20brainsWhat's the Big Idea?
A funny thing happened with the invention of fMRI imaging. Rather than explaining away the mysteries of human experience, the technology that made it possible to visualize and map brain activity for the first time only further complicated our understanding of how the mind works.

Yes, we can say with an amazing degree of certainty which parts of the brain “light up” during specific events (falling in love, having an orgasmdealing with money), but the theory that there’s a single area responsible for each of these complex experiences is as outdated as phrenology. Instead, neuroscientists see patterns and associations, correlations and links.

Satisfactory definitions of philosophically loaded concepts like perception and thought remain as elusive as they’ve always been. If physicists can find the “God particle” with a Hadron collider, then why, given their sophisticated tools, have neuroscientists failed to unlock the black box of consciousness?

Even with the ability to photograph the brain, “you don’t settle philosophical disputes lickety-split,” says Alva Noë. Noë is a philosopher and a member of the Institute for Cognitive and Brain Sciences. He argues that contemporary neuroscience is guided by a few assumptions, chief of which is that the world occurs inside our heads – that the brain makes the world. In this framework, experience is understood as a pattern of sensory stimulation perceived by our hands, feet, eyes, and ears.

The claim that we can come to know the world by breaking it down into smaller parts and observing how they work, then applying those principles to larger questions, is an epistemological perspective called reductionism. Reductionism informs the methodology of much modern biological research, and it's more problematic in practice than in theory. For instance, one of the primary debates about it is whether classical genetics can be reduced to molecular biology.

Reductionists believe that memories, emotions, and feelings can be broken down to nothing more than interactions between brain cells and their associated molecules. In other words, "you" are your brain.

“Of course that’s a very old idea,” says Noë. “It’s almost as if each of us is a submariner in a submarine and we’re traveling around. There are no windows on the submarine. We know nothing about the world around us other than the data we pick up, and we try to construct some model of what’s going on outside, but we’re trapped inside. For most neuroscientists who think about consciousness, the assumption is that we’re trapped inside our heads.”

Our modern understanding of the mind-body problem owes much more to Descartes’ theory of dualism than we'd think. Descartes theorized that the body and mind were two entirely separate entities. Thought existed on an entirely different plane than the physical. "On the other hand, the contemporary scientists they say, 'No, it’s the brain that’s the thing inside of you that does all that, it’s not the soul, the immaterial spirit. The truth of the matter is we don’t have any better idea today how the brain accomplishes what the spirit was supposed to accomplish. Sorry. We don’t have a better idea today how the brain does that than Descartes had how immaterial soul stuff does that."

Contemporary neuroscience follows Descartes in conceptualizing consciousness as something that occurs internally. The difference is that for Descartes, the soul was the ghost in the machine, while for neuroscientists, the ghost is the machine. Neither paradigm manages to capture the texture and dimension of conscious experience, according to Noë.
Consider this; we are conscious of both more and less than affects our nervous system. Let me give you an example. I look at a tomato. It’s sitting there on the counter in front of me. It’s red and bulgy and three dimensional and I experience all that visually. I have a sense even visually of the back of the tomato, but I can't see the back of the tomato. It’s out of view and yet it’s part of my experience of the tomato that it has a back. It’s present in that sense to me, but note it doesn’t strike my retina. It’s present. It informs. It structures my visual experience without actually being an element that stimulates my nervous system.
What's the Significance?
More "shows up" for us or is present in our perception of the world than what is transmitted by the nervous system. What we experience depends on our past -- on what we know, what we've learned, how we've learned it.

This is an exciting time to be studying human nature, but not because of functional magnetic resonance imaging. It's the breakthroughs in our study of the brain that are interesting. "I want to underline that my own criticism of recent neuro-scientific approaches to consciousness is not a criticism of the scientific study of consciousness," Noë explains. "It’s urging that the science gets better and that it shed certain straight-jacketing individualistic, internalistic assumptions, assumptions that are really holding a general science of human nature back."

One of the striking developments of modern times is an appreciation of how unbounded things are. Social networks have transformed our understanding of the nature of the individual. Phones allow another person to be present to us even when they are miles away, destroying the illusion of boundaries.
I travel and I can access my latest work documents, my deepest, most intimate thoughts on the cloud, so where are my most deepest, most significant thoughts? Where am I working? Where am I located? We ourselves are distributed dynamically, extended beings who are always becoming through our action. That is a very profound, new way of thinking about what we are. But sadly so often in the sciences of mind, this new way of thinking about ourselves is overlooked as a possibility. Too many cognitive scientists, not all, but the majority tend to take really a 17th century conception of the person as an individual island trapped inside his or her head. We need to break free of that.
Now, the only way to move forward is through an integrated, contextualized neuroscience of consciousness.

René Descartes's illustration of dualism. Inputs are passed on by the sensory organs to the epiphysis in the brain and from there to the immaterial spirit.

Title image courtesy of Dualism image courtesy of Wikimedia Commons.

Making Sense of Jürgen Habermas - Three Books

In the Marx and Philosophy Review of Books - in the Reviews section, Michael Reno reviews three books about Jürgen Habermas.Irrespective of the place Habermas holds in the integral world as a result of Ken Wilber's promotion of his ideas and work, Habermas is one of the most influential living philosophers of our time. These three books offer brief introductions to his ideas, with lesser or greater success.

Marx & Philosophy Review of Books

Reviews » Jürgen Habermas
Barbara Fultner (ed.)
Jürgen Habermas: Key Concepts
Acumen, 2011. 264pp., $24.95 pb

David Ingram
Habermas: Introduction and Analysis
Cornell University Press, Ithaca and London, 2010. 360pp., $19.95 pb

Lasse Thomassen
Habermas: A Guide for the Perplexed
Continuum, London, 2010. 182pp., $18.96 pb

Reviewed by Michael Reno 

Michael Reno recently finished a dissertation on Adorno and is a Visiting Instructor in the Department of Philosophy at Michigan State University. He can be contacted via email:


With a good part of the world in the throes of economic and political crises—particularly relevant for Habermas are the economic crises in the eurozone and the political situation in Greece, which threatens the unity of the eurozone—the publication of several books attempting to synthesize and present Habermas’s oeuvre is timely. For, Habermas is the most influential social theorist of the last half-century. And, given his recent attempts to prod Europeans toward democratic political integration as the solution to economic crisis and anti-democratic centralization on the part of European elites, especially those in Berlin and Paris, it is worthwhile to consider the theoretical basis for his calls to double down on the project of European unification.

Whatever one may think about the rash of introductory volumes on important thinkers over the last decade, the synthesis and simplified presentation of Habermas’s thought is no enviable task. The sheer number of other thinkers digested into Habermas’s system presents a challenge to the would-be summarizer. In addition, Habermas is no dilettante; he assumes his readers already possess more than a basic understanding of the thinkers integrated into his system. Each of the volumes begins with mention of this difficulty, but has differing strategies for dealing with it.

Thomassen’s strategy is perhaps dictated by his writing as part of the `A Guide for the Perplexed’ series. The series is clearly targeted at intermediate to advanced university students for whom the primary texts are simply too difficult to tackle without help. Thus, in the main, Thomassen limits himself to an overview of Habermas’s ideas, stripped of much their historical relation to other thinkers. After a fairly brief biographical introduction, Thomassen orients his presentation around the notion of the public use of reason, which, as he notes several times in the introduction, “runs like a red thread through Habermas’s work” (14). In the context of the European response to the global economic crisis, this is particularly apt. After adequately summarizing Habermas’s version of Adorno and Horkheimer, more generally situating Habermas in the critical theory tradition (chapter 1), and offering an account of Habermas’s changing conceptualization of the public sphere (chapter 2), Thomassen presents two key aspects of Theory of Communicative Action: formal pragmatics and the colonisation thesis (chapter 3). Thomassen’s effort is admirable for the way it clearly and concisely spells out the evolving characterizations of the relationships between system and lifeworld in Habermas’s work (chapter 5). In the earlier works, up through Theory of Communicative Action the solution to the system’s colonisation of the lifeworld is to “build a bulwark around the lifeworld, protecting it against the system” (118). While the more nuanced approach of the later works—Between Facts and Norms, particularly—invokes the notion of sluices or censors through which the system imperatives of the state and economy can be mediated by democratic engagement and lifeworld concerns. The communicative power of weak publics can be brought to bear on administrative power through the strong public of the legislature. Chapter 5 on deliberative democracy captures Habermas’s attempts to mediate several dichotomies in legal theory: natural law and positivism, liberalism and republicanism, constitutionalism and democracy, and shows the tensions in this attempt brought to the fore through civil disobedience. The last chapter (chapter 6), too, in presenting Habermas’s cosmopolitanism in relation to his public stance on the European polity and the NATO bombing of Serbia in response to conflict in Kosovo, offers a way into Habermas’s most recent public pronouncements regarding Europe. At least in the abstract then, Habermas’s calls for engagement on the part of European publics as well as the protests sweeping Greece and the rest of Europe can be understood in the Habermas presented by Thomassen. It is to the book’s credit that despite its brevity, even the uninitiated reader is given some conceptual tools with which to address contemporary economic and political conflict.

Ingram’s ability to review the entirety of Habermas’s corpus shows up the constraints of attempting an introduction to a key thinker from within one of the already existing series dedicated to this goal. Like Thomassen’s work, Ingram first offers a biographical introduction coupled with a philosophical contextualisation. Following this, he, alone among the volumes under review, devotes an entire chapter to Knowledge and Human Interests (chapter 2). Ingram’s account provides its best insights in the nuanced presentation of the complicated relations between state, economy, and lifeworld; Ingram spends four of the book’s eleven chapters (chapters 6-9) detailing the conflicts between law and democracy, an additional chapter on the social pathologies of late capitalism (chapter 10), four of the six appendices on aspects of social theory, and the last chapter (chapter 11) of the book re-contextualising Habermas’s understanding of social development and conflict within Marxist and critical theory traditions.

Ingram’s piece is a complicated attempt to not only present Habermas’s philosophy and social theory in an accessible way, but also an interpretative claim about Habermas’s solutions to the problems of modernity and thus his relationship to Marx, Weber, and the earlier generation of Frankfurt School thinkers. This is an asset for understanding the current economic crisis and the political crises that have followed in its wake. Ingram’s summation of Habermas’s tri-level model of global governance in the penultimate chapter paired with the account of social learning given in the last chapter, Postsecular Postscript, at least makes it plausible why one would turn to Habermas in order to understand contemporary events, rather than, say, merely turning to Marx. These chapters especially show that Habermas not only offers a way to understand class conflict in the mediated terms of social pathologies that emerge in response to system imperatives finding their way into the lifeworld and/or the uneven cultivation of rationalization complexes (319), but also makes clear why global governance with actual democratic input from the people is required to solve system crises that inevitably emerge in the globalized economy. Indeed, Ingram focuses on the current economic crisis as a test case for Habermas’s theory of global governance, pointing out that “Habermas may have underestimated the extent to which the new global economy breaks with the older form of welfare capitalism and its state-centered presuppositions” (303).

Jürgen Habermas: Key Concepts, approaches the difficult problem of synthesis through a division of labour among specialists in crucial areas of Habermas’s thought. So, it more effectively handles the way in which Habermas draws from and alters other thinker’s insights than Thomassen’s piece. The thinkers brought together by Fultner are among the best of the current crop of scholars seriously engaged with Habermas and teaching at North American institutions; several of the authors have also translated important works by Habermas into English. After Fultner’s introduction, Max Pensky gives an intellectual biography, which, in Habermasian fashion situates the philosopher between immanence and transcendence.

Those interested in an introduction to Habermas’s theory of language, especially those coming to Habermas via analytic approaches to philosophy of language will be best served by Habermas: Key Concepts. As Ingram admits in his third chapter, The Linguistic Turn, he barely gives “Habermas’s theory of language the attention it deserves” (87), though it is more extensive than the account in Thomassen’s work. Though Ingram offers an appendix on Brandom, and his chapter on language is adequate as far as it goes, Barbara Fultner’s chapter (chapter 3) on Habermas’s formal pragmatics along with Melissa Yates’s on the meaning of post-metaphysical thinking (chapter 2) better situate Habermas’s appropriation of speech act theory and his formal pragmatics in relation to the key analytic philosophers of language. Particularly useful in this regard are Fultner’s endnotes, which list the key Habermas texts addressing these analytic thinkers.

This is not to deny the quality of the contributions relevant to understanding social crisis. Joseph Heath’s presentation in “System and Lifeworld” (chapter 4) in Key Concepts is a model of clarity. And it is alone in adequately situating the colonisation thesis in terms of Parsons’s account of social subsystems. Haysom’s contribution (chapter 9), one of the most critical, provides an account of the changing place of social conflict in Habermas’s system. In summarizing the role of social movements in the mature account of Between Facts and Norms, Haysom notes, “Habermas’s account allows for the fact that in the normal course of events, initiative lies not with civil society, nor even with parliaments or legislatures, but with senior members of government and administrative bureaucracy” (191). This critical stance is echoed by Cronin’s account of cosmopolitan democracy (chapter 10), in which she wonders “what is left of popular sovereignty” in an international system which depends on governmental and media elites for legitimacy (218). This tension between the social integrative role of law in contemporary societies and the anti-democratic aspects of Habermas’ theory of law are nicely highlighted in Zurn’s piece on the discourse theory of law (chapter 8). These critical accounts are balanced by Olsen’s chapter on deliberative democracy (chapter 7), in which he notes the above problems regarding the potential inability of democratic will-formation to be appropriately taken up in the strong public of the legislature. But concludes that this “problem awaits further discussion between Habermas and his critics” (150).

Habermas’s discourse ethics are taken up by Ingram in chapter 5 and William Rehg’s contribution to Key Concepts (chapter 6). Rehg’s work on Habermas is indispensable, as evidenced by Ingram’s repeated citation of him in his own chapter. But, by offering short summaries of meta-ethical positions (to which the universalization principle answers) and normative ethical positions (to which the “discourse principle” answers) and Piaget and Kohlberg’s developmental theories, Ingram’s chapter better situates discourse ethics in the context of moral philosophy and developmental psychology. Rehg does, in articulating the assumptions of the universalization principle, connect Habermas to the Kantian moral tradition. His account is concerned to articulate the theory to the uninitiated and show the plausibility of discourse ethics for dealing with real moral conflicts, both public and private, rather than the more philosophic ethical concerns of Ingram’s account. In these aims, Rehg’s account succeeds, but also points out the motivation problem in post-conventional accounts of ethics, offering the theory, in the end as conditional upon both the internal structure of moral discourse and the nature of the society in which the discourse occurs (137). Rehg’s account thus characterizes Habermas’s ethics as answering to the modern problems of both autonomy and solidarity.

The questions of personal and political identity are also addressed in both Ingram’s work and Joel Anderson’s contribution (chapter 5) to Key Concepts. Anderson attempts an abstract reconstruction of intersubjective concepts of autonomy and authenticity. Ingram argues that Habermas understands feminism and multiculturalism as struggles against exclusion from equal citizenship. Ingram’s account concludes with an embrace of the gestures toward the aesthetic cultivation of self that are sprinkled through Habermas’s work—despite the emphasis on intersubjectivity and reason, we remain embedded in the search for identity that marks modern subjects. This is similar to the account Mendieta (chapter 11) offers of Habermas’s evolving views on religion, secularization, and rationalization. Religion takes up an inspirational role whose semantic content cannot be reduced to reason or philosophy. Given Habermas’s dismissal of his predecessors in the Frankfurt School, who took alienation and anomie as serious problems of capitalist development, I find these recent moves less than compelling.

Thomassen’s volume will be useful for those completely unfamiliar with Habermas’s work. The other two works are useful not only for a more advanced reading of Habermas, but for offering tools for understanding our current economic crises and the political responses to those crises. They both give the sense that the current crises are tests of Habermas’s system. The prospect of the failure of the European Union rightly concerns Habermas, as this seems to be where he has placed his bets as a public intellectual. And, indeed, since his theory of a democratic international politics, as well as his theory of national law argue that the subsystems of government and market are necessary to deal with the complexities of contemporary societies, the current crises provide a test case not just for Habermas’ social theory, but his unflagging optimism.
18 June 2012

Thursday, August 09, 2012

Early Meat-Eating Human Ancestors Thrived While Vegetarian Hominin Died Out

Make of this what you will . . . but it seems to support the premise that humans are omnivores. Before the commentary from Katherine Harmon at Scientific American, here is the story form Science Daily.

Early Human Ancestors Had More Variable Diet

ScienceDaily (Aug. 8, 2012) — New research sheds more light on the diet and home ranges of early hominins belonging to three different genera, notably Australopithecus, Paranthropus and Homo -- that were discovered at sites such as Sterkfontein, Swartkrans and Kromdraai in the Cradle of Humankind, about 50 kilometres from Johannesburg. Australopithecus existed before the other two genera evolved about 2 million years ago.

Scientists conducted an analysis of the fossil teeth, indicating that Australopithecus, a predecessor of early Homo, had a more varied diet than early Homo. Its diet was also more variable than the diet of another distant human relative known as Paranthropus.

An international team of researchers, including Professor Francis Thackeray, Director of the Institute for Human Evolution at Wits University, will be publishing their latest research on what our early ancestors ate, online in the journal, Nature, on August 8, 2012. The paper titled 'Evidence for diet but not landscape use in South African early hominins' was authored by Vincent Balter from the Ecole Normale Supérieure in Lyon, France; Jose´ Braga from the Université de Toulouse Paul Sabatier in Toulouse in France; Philippe Te´louk from the Ecole Normale Supérieure in Lyon in France; and Thackeray from the University of the Witwatersrand in Johannesburg in South Africa.

According to Thackeray, the results of the study show that Paranthropus had a primarily herbivorous-like diet, while Homo included a greater consumption of meat.

Signatures of essential chemical elements have been found in trace amounts in the tooth enamel of the three fossils genera, and the results are indicators of what South African hominins ate and what their habitat preferences were.

Strontium and barium levels in organic tissues, including teeth, decrease in animals higher in the food chain. The scientists used a laser ablation device, which allowed them to sample very small quantities of fossil material for analysis. Since the laser beam was pointed along the growth prisms of dental enamel, it was possible to reconstruct the dietary changes for each hominin individual.

Thackeray states that the greater consumption of meat in the diet of early forms of Homo could have contributed to the increase in brain size in this genus.

Australopithecus probably ate both meat and the leaves and fruits of woody plants. The composition of this diet may have varied seasonally.

Apart from the dietary differences, the new results indicate that the home-range area was of similar size for species of the three hominin genera.

The scientists have also measured the strontium isotope composition of dental enamel. Strontium isotope compositions are free of dietary effects but are characteristic of the geological substrate on which the animals lived.

According to the results all the hominids lived in the same general area, not far from the caves where their bones and teeth are found today.

Professor Vincent Balter of the Geological Laboratory of Lyon in France, suggests that up until two millions years ago in South Africa, the Australopithecines were generalists, but gave up their broad niche to Paranthropus and Homo, both being more specialised than their common ancestor.

That is the press release from the University of Witwatersrand - and here is the commentary on that news. I do not agree with Harmon's conclusion, and she repeats the red meat = health problems nonsense (its all in how it's cooked and where it comes from). Even now, children who do not get adequate protein in development are smaller and have lower IQ scores - and there are many other sources of meat than the drug-filled factory cows the meat industry foists on the market.

Early Meat-Eating Human Ancestors Thrived While Vegetarian Hominin Died Out

early human ancestor tooth varied diet
Early Homo molar; image courtesy of Jose Braga/Didier Descouens

There has been fierce debate recently over whether the original “caveman” diet was one of heaps of bloody meat or fields of greens. New findings suggest that some of our early ancestors were actually quite omnivorous. But subsequently, our line and an ill-fated group of hominins developed very different dietary strategies. One chose meat while the other moved toward more plants.

The hominin Australopithecus, which lived from about 4 million to 2 million years ago, is presumed to be a common ancestor of both the Homo lineage, which emerged some 2.3 million years ago and gave rise to us, and to the Paranthropus genius, which is first documented about 2.7 million years ago and died out about 1 million years ago. Some have attributed the extinction of Paranthropus to an inflexible diet or limited territory, especially in the face of climactic changes.

A team of researchers led by Vincent Balter, of École Normale Supérieure de Lyon, decided to probe into some of these debates. They used lasers to analyze the enamel from fossilized teeth belonging to Australopithecus africanus, Paranthropus robustus and early Homo specimens, which were all from southern Africa. By assessing ratios of calcium, barium and strontium as well as the number of strontium isotopes, the team was able to deduce both diet and the size of the area that these individuals ranged over. The findings were published online August 8 in Nature (Scientific American is part of Nature Publishing Group).

The ancestral Australopithecus consumed a wide range of foods, including, meat, leaves and fruits. This varied diet might have been flexible to shift with food availability in different seasons, ensuring that they almost always had something to eat. Paranthropus, according to the elemental analysis, was largely a plant eater, which matches up with previous studies of tooth morphology and wear patterns. It also helps to explain the massive jaw structure they possessed, which could have come in handy for tough food stuffs and earned one specimen the nickname “nutcracker man.” Early Homo, on the other hand, went in for a meat-heavy diet—possibly enabled by the use of tools for hunting and butchering.

However, just because a meatier diet was good for our early Homo forbearers does not necessarily it will keep each of us contemporary humans alive longer. Now that we no longer have to fend for ourselves in quite the same way, increased red meat consumption has actually been linked to shorter individual life spans. So next time you’re flummoxed by food choices, don’t be afraid to go a little Paranthropus and hit the salad bar.

Katherine Harmon 
 About the Author: Katherine Harmon is an associate editor for Scientific American covering health, medicine and life sciences. Follow on Twitter @katherineharmon.
The views expressed are those of the author and are not necessarily those of Scientific American.