I am now two-thirds done with my psychiatry rotation. It has been a fascinating experience so far. I’ve seen the gamut of psychiatric cases, depressed people who cut their necks through and through, to florid schizophrenics worried that the Hiroshima bomb will go off any moment. The treatment of psychiatric conditions like depression or schizophrenia often revolves around regulating monoamine neurotransmitters like serotonin, norepinephrine and dopamine.
Dopamine is an important neurotransmitter that functions in a lot of behaviors and reactions, such as movement, lactation, aggression, fear, etc. In diseases like Parkinson, dopamine levels lower and movement becomes uncontrolled. In other diseases like schizophrenia, either dopamine levels are high or response to dopamine is higher, and paranoia & hallucinations manifest. Treating schizophrenia involves blocking dopamine receptors. As you can imagine, a common side effect of antipsychotics is movement disorders — or Parkinsonism.
So why am I on this neuropsychiatric kick on an anthropology blog? Our cultural and behavioral predisopostions ultimately boil down to chemicals in our brain interacting and stimulating other areas. One of the most important functions of dopamine is in the reward system of the brain, an area called the nucleus accumbens that primes pleasurable behavior to repeat, such as sex, eating, and drugs.
In this video, Robert Sapolsky of Stanford Neurology makes the distinction between how dopamine levels rise in the anticipation of pleasure and not as a response to pleasure. I especially like that comment he made regarding reward and religion, “There’s no monkey out there willing to lever press because St. Peter is down the line.”
Oil transformed Dubai in the 1970s. The city now boasts the world's tallest building, giant malls, and some two million residents, who depend on desalinated seawater and air-conditioning—and thus on cheap energy—to live in the Arabian desert. (Credit: Jens Neumann/Edgar Rodtmann/NATIONAL GEOGRAPHIC)
To paraphrase Carl Sagan, science has a way of deflating human conceits. Anthropology reveals that humans are special – just not for many of the reasons proposed throughout our history. Thanks to biology, astronomy, and geology, we now know that:
Modern humans are one species among many, not the pinnacle of all creation.
We’re not the center of the universe; our planet orbits a fairly average star.
We haven’t been around since the beginning of time – far from it.
On a 4.5-billion-year-old planet, with a 3.5-billion-year history of life, anatomically-modern Homo sapiens only go back about 200,000 years. We’re brand new, a tiny blip on the geologic time scale! Despite this, a new National Geographic article explores the possibility that the “Anthropocene” may have already begun. Here is a brief excerpt:
Enter the Anthropocene—Age of Man It’s a new name for a new geologic epoch—one defined by our own massive impact on the planet. That mark will endure in the geologic record long after our cities have crumbled…Probably the most obvious way humans are altering the planet is by building cities, which are essentially vast stretches of man-made materials—steel, glass, concrete, and brick. But it turns out most cities are not good candidates for long-term preservation, for the simple reason that they’re built on land, and on land the forces of erosion tend to win out over those of sedimentation.
The author of the article, Elizabeth Kolbert, graciously agreed to an interview with Anthropology.net. The text of our discussion, conducted via e-mail, follows:
Fancher: The greatest strength of anthropology is its all-encompassing view of humanity. We’re proud of this breadth, frequently describing our work as the study of all people, in all times, and all places. But, as you state in your article, stratigraphers take an extremely long view – the entire 4.5-billion-year history of Earth. How can students of the human past benefit from this geological perspective?
Kolbert: I’m not sure I have a good answer for this. As all anthropologists know, we are a young species. So human history doesn’t tell us much about earth history. What is particularly alarming about a lot of recent discoveries in geology is that you have to go way, way back – i.e., tens of millions of years – to find analogues for some of the things we are doing today, like, for example, acidifying the oceans.
Fancher: I was surprised to read that our proudest technological achievements might not be easy to recognize in the geological record. It’s humbling to think that urban centers will ultimately be as fleeting in the geological record as short-term hunter-gatherer camp sites are in the archaeological record. Despite our human desire to leave huge, everlasting monuments, is it better not to be noticed in the geological record?
Kolbert: Well, it’s not clear that we will be noticed, because it’s not clear there’s going to be anything around to notice us. But we will be noticeable. And certainly from the standpoint of the other organisms on earth, it would be a lot better if our impact were not so obvious.
Fancher: Some issues of scientific classification appear to have little practical relevance. For example, the debate over whether Pluto qualifies as a planet or not. In your article, Dutch chemist Paul Crutzen concludes that the value of the Anthropocene classification goes far beyond textbook revisions. Can you elaborate on the meaning of the Anthropocene?
Kolbert: Officially, we live in the Holocene, or “wholly recent” epoch. The Anthropocene translates basically as the man-made epoch. It’s an acknowledgment that humans, rather than what are sometimes quaintly called “the great forces of nature,” have become the driving force on the planet.
Fancher: How might recognition of a geological epoch called the Anthropocene influence human behavior?
Kolbert: I end the piece with a quote from Paul Crutzen, the Nobelist who coined the term. Crutzen says, “What I hope is that the term ‘Anthropocene’ will be a warning to the world.” I think what he means by that is: we are now in the driver’s seat. Unfortunately, we don’t really know how to operate the vehicle. So we’d better think about what we’re doing very carefully.
Many thanks to Elizabeth Kolbert for writing such a thought-provoking article, and for agreeing to this interview. Enter the Anthropocene – Age of Manis part of National Geographic magazine’s year-long coverage of the global human population reaching 7 billion.
What do you think about the possibility of a geological epoch called the Anthropocene?
“Anthropologists Trace Human Origins Back To One Large Goat”
‘Wait, That Can’t Be Right,’ Scientists Say”
In addition to being funny, the article, by contrast, helps show the strict standards of evidence, interdisciplinary collaboration, and peer-review process of actual paleoanthropological research. Also, our close relationship with other primates is highlighted when one fake Onion researcher observes that “…humans don’t look like goats.” In other words, don’t expect any presentations on “goat people” at professional anthropological conferences anytime soon. Enjoy!
Carol Ward1, William Kimbel, and Donald Johanson have published a paper in Science on the arch seen in a newly discovered fourth metatarsal of Australopithecus afarensis (AL 333-160). A lot of the popular press are publishing misleading headlines that this proves bipedalism in australopithecines. No, we’ve known they were bipedal — we just didn’t have a true idea as to what extent they were bipedal. So a find like this helps investigate the degree of bipedalism.
AL 333-160 left fourth metatarsal in dorsal, lateral, medial, plantar, and proximal views.
How does this tell us how bipedal A. afarensis were?
) Box plots of angular relations of the proximal and distal metatarsal ends to the diaphysis in chimpanzees, gorillas, humans, and AL 333-160.
If you’ve ever had the pleasure of visiting a podiatrist, you’d know flat feet are not conducive to bipedalism. The two-way arch helps support upright walking and distribute recoil force. Other great apes like, chimps and gorillas have flatter feet than us. The authors of this paper confirmed this by comparing the fourth metatarsal of chimps, gorillas, and humans to AL 333-160.
On all their comparisons, AL 333-160 fell within range of humans. There were some occasions where there’s a lot of gray area which I’ll address later. Nonetheless, to the right you can see the best comparison, in my opinion, which the comparison of the arch of the diaphysis of the bone between the two species. You can have a look at the rest of the figures here.
The problem I am seeing here is that this metatarsal is not Lucy’s (AL 288-1). AL 333 is designated to fossils from the site where the “First Family” came from and not the same locality as AL 288. Nonetheless, they are not the same individual. Kimbel is quoted in the BBC News, saying,
“Lucy’s spine has the double curve that our own spine does,” Professor Kimbel said.
“Her hips functioned much as human hips do in providing balance to the body with each step, which in a biped of course means that you’re actually standing on only one leg at a time during striding.
“The knees likewise in Lucy’s species are drawn underneath the body such that the thighbone, or femur, angles inwards to the knees from the hip-joints – as in humans.
“And now we can say that the foot, too, joins these other anatomical regions in pointing towards a fundamentally human-like form of locomotion in this ancient human ancestor.”
This is a flawed association to make; a form of what I would call confounding bias. We don’t have Lucy’s 4th metatarsal to see what it looks like and unfortunately we don’t have the rest of the this specimens skeleton to say it looked like Lucy’s. In fact, we have very little australopithecine appendicular and skeletons other than AL 288-1 (most notable are AL 129-1 and STS 14). So how can Kimbel say that the foot joins other anatomical regions when we don’t know what the other regions really looked like?
See, the n of this sample is 1. Looking at the intervals in the figures, especially Fig 3 & 4, there a a significant amount of variation in humans and chimpanzees that overlap. Chimps aren’t bipedal but we are. So imagine you are a paleoanthropologist way in the future looking at one metatarsal of a now-current then-ancient chimpanzee way and comparing it to a humans — surely you could make the same conclusion as these three have. And herein lies the big issue with sensationalism… as is the problem often in paleoanthropology, we just don’t have many comparative samples but people want definitive conclusions.
Ward, C., Kimbel, W., & Johanson, D. (2011). Complete Fourth Metatarsal and Arches in the Foot of Australopithecus afarensis Science, 331 (6018), 750-753 DOI: 10.1126/science.1201463
Very rarely is an entire family group of hominins buried and fossilized at the same time. It is even rarer for paleoanthropologists to discover such an assemblage. Fortunately for science but unfortunately for the hominins, caves occasionally collapsed on entire social groups.
Map of El Sidrón
At a site known as El Sidrón in Spain, excavations have been ongoing since 2000. To date, 12 Neandertals have been discovered in a context that points to a single geological event, circa 49,000 years ago. A group of 12 Neandertals is consistent with previous estimates of around 10 individuals per group. At least six adults, three adolescents and four younger individuals were buried at once, most likely during a storm. The cold conditions of the cave system and immediate burial of the remains not only preserved the bones well, but were also ideal for DNA.
The remains were sexed based on both morphology and DNA analysis. After sex was determined, anthropologists identified the different Neandertal lineages based on mitochondrial DNA. Several of the adults were found to be male, and the other three female. It was discovered that all three males belong to the same matrilineal group, while each respective female has a different haplotype. When compared to modern Europeans, the authors noted that there is significantly less genetic diversity within the mitochondrial genome.
These results strongly imply that Neandertals exhibited patrilocal mating behavior. Females were the ones who would have changed family groups, not males. This type of insight into an extinct species is unique, thanks to the quality of DNA preservation available at El Sidrón.
Another interesting point of discussion in the study relates to Neandertal interbirth interval. One of the females was linked by DNA to two of the younger individuals, approximately several years apart in age. If the anthropologists are correct about the relationship, this puts the interbirth interval for Homo neanderthalensis at a value similar to hunter-gatherer groups today. This data, if replicated with other Neandertal individuals, could eventually dispel differential reproduction as a potential cause for Neandertal disappearance.
Knowing about Neandertal group dynamics could provide crucial clues as to why they went extinct. Future analysis of the remains recovered at El Sidrón will no doubt give more insights into our closest extinct relatives, and perhaps even why Homo sapiens flourished and Neandertals declined.
By Matthew Magnani
Lalueza-Fox, C., et al. (2011). “Genetic evidence for patrilocal mating behavior among Neandertal groups.” PNAS. January 4, vol. 108 no. 1 250-253.
Endurance running has been cited since the 1980’s as a possible explanation for the modern human body plan. Past studies have focused on the running abilities of species such as Homo ergaster and Homo sapiens, with little or no mention of other species or genera. Currently in press in the Journal of Human Evolution is a discussion of Neandertal running capabilities.
The authors observed the length of the calcaneal tuber of the foot, which correlates with how far the Achilles tendon will stretch during movement. For this study measurements were taken of both Homo sapiens and Homo neanderthalensis. Species with short calcaneal tubers stretch their Achilles tendons to a greater degree, which is then returned in the form of elastic energy. Species with long tubers stretch the Achilles tendon less and therefore have a lower return of elastic energy.
White Line: Calcaneus tuber length. Red Line: Achilles tendon moment. Correlation between the two values. Photo from Raichlen et al.
Simply put, a species with shorter calcaneal tubers will use less energy when running. Anatomically modern humans have been found to have short tubers, while longer ones are found on Neandertal remains. According to the authors, this variation has significant behavioral implications.
Unlike modern humans, the storage of less elastic energy in Neandertals would have made running less efficient. However, Neandertals were not necessarily at a disadvantage in the colder climates they are often said to have inhabited. It is more likely that running over long distances would have been energetically costly to them, without having huge benefits.
Long distance running would prove beneficial in warmer climates where animals are prone to hyperventilate when chased. Modern humans would have benefitted from endurance running because it would have aided in capturing prey. The same model does not necessarily apply in colder climates. A runner could chase an animal all day in low temperatures and never have the animal succumb to heat stress or hyperventilation. It is for this reason argued that the ability to run long distances would not have been as evolutionarily valuable to Homo neanderthalensis.
Discussing endurance running provides fascinating insight into human evolution. While the ability to run long distances can be very revealing about evolutionary history, lack of endurance can be as well.
By Matt Magnani
Raichlen, D.A., Armstrong, H., Lieberman, D.E. (2011). “Calcaneus length determines running economy: Implications for endurance running performance in modern humans and Neandertals.” The Journal of Human Evolution. Article in Press.
A hunter-gatherer mother sits stirring a pot of stew over an open fire. Her young son, eagerly anticipating the evening meal, approaches the pot and asks, “What are we eating?” “Not sure. Meat, I think. Probably some other stuff,” she replies.
Okay, I made that up. The preceding exchange would never occur between hunter-gatherers. Or horticulturalists. Or pastoralists. Or most of the other subsistence systems that anthropologists study. The mother, and usually the son, would know what was in the pot because they took part in hunting, gathering, raising, growing, or processing the ingredients. And that’s pretty much the way it’s been for the vast majority of human history.
So how did we end up here? An Alabama law firm is suing Taco Bell, claiming that the meat used in Taco Bell’s products does not meet the U.S. Department of Agriculture definition of “beef.” In fact, the lawsuit alleges that the company’s meat filling is only 35% beef, with the remainder comprised of non-meat ingredients such as water, oats, modified corn starch, maltodextrin, etc.
Taco Bell asserts that their products contain 100% beef.
That’s a big difference in percentages. Someone’s not telling the truth, or is at least being very disingenuous. Thankfully, we humans have an established method for evaluating evidence-based claims…SCIENCE! Yes, I can turn anything into an advertisement for science, and I hope the legal proceedings rely on solid data to resolve this dispute.
From an anthropological perspective, this issue highlights the wide, historically-unprecedented, gap between food production and food consumption in 21st Century developed nations. We’re all food consumers, far fewer of us are food producers. The production of our food most often occurs out of sight. Michael Pollan [In Defense of Foodand the film Food, Inc.] argues that much of what we eat is not even food in the strict sense, but rather “food products,” manufactured from food and the “other stuff” I mentioned before.
Many people seem repelled by the idea of unidentifiable “meat.” But, like our Paleolithic ancestors, we crave fat, salt, and sugar [Martin Jones' Feast: Why Humans Share Foodand Richard Wrangham's Catching Fire: How Cooking Made Us Human]. Fast food provides massive quantities of all three for a low, low price. I had Taco Bell a few days ago, so I understand the allure of quick, cheap calories. How we got to this point is a fascinating story, well-covered by anthropological research (please see included links and share your own in the comments). Since we are so removed from the production of our own food products, I think it’s reasonable for consumers to know what’s in the pot – even if laboratory analysis is required to figure out the ingredients. What do you think?
If you don’t follow or subscribe to our sister blog Primatology.net, I want to make you aware of an anthropological post I just put up on the newly published orangutan genome. Click here to read about some of the findings, but to wet your appetite, it involves the estimated divergence of the two orangutan species at 400,000 years ago, the relative stabilitiy of their genomes compared to human and chimpanzee, and lastly the shared similarities between human and orang, and not orang and chimp.
Sumatran Orangutan (Pongo abelii)
For quick access to the primary sources, the full citations to the papers discussed are below this read more link.
“It is a project to analyze (autosomal) genetic data of participants of South Asian origin for the purpose of providing detailed ancestry information. So the focus of the project is on South Asians: Indians, Pakistanis, Bangladeshis and Sri Lankans.
The project will collect 23andme raw genetic data from participants to better understand the ancestry relationships of different South Asian ethnicities.
There was a nice deal running on 23andme about a month ago for their ancestry & health kit that worked out to be $160 for 1 year. I hopped on board, got my kit, spat in the tube and sent it off. It is currently being analyzed. My ancestry is one of the populations Zack is looking for — so I’ll be sending my data to him. I can’t wait.
If you have had a 23andme genetic testing, you should consider participating in this project. It looks to be very interesting.
Razib has done rounded up a nice review of Dienekes‘ Dodecad data to answer some prelim questions on the genetic of Ethiopia. Ethiopia is a very interesting cultural and paleontological area of the world. I had the pleasure of being a part of a field group several years ago and had a wonderful time. A good summary of the ADMIXTURE analysis done by Dienekes, reorganized by Razib, is shown below:
