An international team of researchers has announced the discovery of Afrasia djijidae, a new fossil primate from Myanmar that illuminates a critical step in the evolution of early anthropoids—the group that includes humans, apes, and monkeys. The 37-million-year-old Afrasia closely resembles another early anthropoid, Afrotarsius libycus, recently discovered at a site of similar age in the Sahara Desert of Libya. The close similarity between Afrasia and Afrotarsius indicates that early anthropoids colonized Africa only shortly before the time when these animals lived. The colonization of Africa by early anthropoids was a pivotal step in primate and human evolution, because it set the stage for the later evolution of more advanced apes and humans there. The scientific paper describing the discovery appears today in Proceedings of the National Academy of Sciences.... Read more »
Leigh Kish, & Carnegie Museum of Natural History. (2012) Fossil Discovery Sheds New Light on Evolutionary History of Higher Primates. Carnegie Museum of Natural History. info:/
Uganda and the Democratic Republic of Congo have been bedeviled by viral hemorrhagic fever outbreaks this year. Since the summer, Ebola and Marburg have appeared throughout the two verdant countries killing dozens of people. Both countries are incredibly rich and diverse in their ecology - the Congo Basin is one of the largest and densely forested regions in the world - and much of their economy depends upon safari tourism and gorilla trekking. The livelihood of their peoples is also greatly reliant on poaching and bushmeat; for many in the DR Congo, primates, ungulates, primates and rodents are often their only form of animal protein considering the prohibitive cost of raising or purchasing domesticated animals for food.... Read more »
Nasi, R., Taber, A., & Van Vliet, N. (2011) Empty forests, empty stomachs? Bushmeat and livelihoods in the Congo and Amazon Basins. International Forestry Review, 13(3), 355-368. DOI: 10.1505/146554811798293872
Paula Broadwell, the aggressive competitor. Photo from her Facebook page. By now, you’ve probably heard all about Paula Broadwell, the woman that seduced the notoriously disciplined CIA director, four-star US Army general, husband and father, General David Petraeus. What kind of a woman might be able to sway a man that has such admirable self-control? Broadwell was Petraeus’ biographer, a West Point graduate with a Harvard graduate degree, an Army Reservist thrice recalled to active duty, a fitness champion, Ironman triathlete and even a machine gun model. Her accomplishments are clearly impressive, but maybe the key comes down to her competitive nature. I mean, she did send several threatening e-mails to an attractive socialite and Petraeus family friend, warning her to stay away from her (other) man.When we think about competing for mates, we generally think about males competing for females and breeding territories with horns to duke it out, or elaborate feathers to show off, or dance-offs to demonstrate their physical abilities. But females often have to compete for the high-quality males and breeding territories too. And many of the concepts that apply to males competing for females have been found to also apply to females competing for males.A dark-eyed junco thinking "What you lookin' at?". Photo by Kristal Cain.As much as we know about males competing with one another, we know surprisingly little about females competing with one another, although they clearly do. Kristal Cain and Ellen Ketterson at Indiana University sought out to shed light on female competition and its effect on breeding success. They did this with female Carolina dark-eyed juncos, a socially monogamous songbird species in which both parents care for the young. They were curious whether more aggressive females would also have other competitive traits, like large body size. They also wondered whether aggressive females would have better breeding success.The researchers caught female juncos to measure and put identifying leg bands on them. They then released them and spent their nesting season looking for their nests. When they found a nest, they identified whose nest it was by the female’s leg bands. The researchers tested how aggressive females were towards competing females by placing a caged female within 3 meters of a subject’s nest and watching to see if she swooped at the caged female. Then they kept an eye on the nest to see if the chicks all survived until they fledged (left the nest on their own) or if the nest was destroyed (usually by a predator) before the chicks fledged.A female junco in full-on attack mode. Photo by Kristal Cain.Females that were more aggressive towards “competing” females tended to be bigger and had chicks that were more likely to fledge. Now, if this were a story about competitive males, we might think big aggressive males with more successful chicks might have higher testosterone. Alternatively, low testosterone is often found in males that are better fathers. But these are females… Does it even make sense to talk about testosterone in females? Of course it does! Turns out, males don’t have a monopoly on testosterone; females have it too.The researchers drew blood from the females and then gave them a “testosterone challenge” by injecting them with a hormone called gonadotropin-releasing hormone (or GnRH for short). GnRH is a trigger that causes a series of biological events that result in the gonads producing more hormones, including testosterone. The researchers then drew a second blood sample to measure how much testosterone levels changed in response to the GnRH injection.More aggressive females produced more testosterone in response to the GnRH injection than did less aggressive females. This same effect has also been shown to be true of males behaving aggressively towards each other. I guess males and females really aren’t all that different, eh? But interestingly, females that produced more testosterone in response to the GnRH challenge also had more successful nests.It’s important to keep in mind that these results are correlational. Maybe testosterone makes females bigger and more aggressive and better mothers. Or perhaps having a temper increases your testosterone production. Or maybe some other hormone that increases in response to GnRH (there are many) is responsible for the effects. In any case, females that are bigger and more aggressive and have more successful offspring also produce more testosterone in response to a GnRH injection. Paula Broadwell shows off her aggressive abilities in this KRISS ARMS video (gif'd by Michael Pakradooni).As far as we know, no one has given Paula Broadwell a testosterone challenge, but she undoubtedly has a number of correlated competitive traits. Paula Broadwell is a competitive, physically fit, attractive parent who has shown that she can out-compete the spouses of high-quality mates… But then again, so is David Petraeus.Want to know more? Check this out:Cain, K., & Ketterson, E. (2011). Competitive females are successful females; phenotype, mechanism, and selection in a common songbird Behavioral Ecology and Sociobiology, 66 (2), 241-252 DOI: 10.1007/s00265-011-1272-5 ... Read more »
Cain, K., & Ketterson, E. (2011) Competitive females are successful females; phenotype, mechanism, and selection in a common songbird. Behavioral Ecology and Sociobiology, 66(2), 241-252. DOI: 10.1007/s00265-011-1272-5
"Do physically attractive women possess particularly attractive inner attributes?"So ask the authors of a study just out in Psychological Science: Don't Judge a Book by Its Cover, Revisited. Their answer? People do tend to judge (female) books by their covers, but we shouldn't.Psychologists Segal-Caspi and colleagues took 118 female Israeli students and videotaped them walking into a room and reading a weather forecast. Then other students - male and female - judged the 'targets' on attractiveness, but also tried to work out their personality, purely based on 60 seconds of video.So what happened?The judges judged prettier women as having stereotypically 'better' personality traits e.g. less neurotic and more friendly. Interestingly, both male and female judges did this, and there were no significant differences between the genders.So there's a tendency to think that those we find attractive are also beautiful on the inside - but, that's all an illusion, say the authors. The targets were also rated themselves on personality, and these self ratings told a different story - there was no correlation between personality and average ratings of attractiveness.There were however some small differences in self-reported values, with attractiveness being associated with valuing tradition and conformity, but not 'self-direction'.So there we have it. Books, covers, don't judge 'em by 'em. It would have been better if this study had included both male and female 'targets', though, and the whole thing does rely on the validity of self-report, though no more than any other psychology paper.The journal Psychological Science has been criticized recently, accused of publishing findings that probably aren't true and wouldn't be interesting even if they were. I don't think that applies to this, though.On the contrary, this is the kind of study that psychologists should do more of.The subject may seem crude, unsophisticated and not very 'scientific' but like it or not, it's one that people care about. Many people have strong views on issues like this (one way or the other), ones based essentially on hearsay, and personal recollections, i.e. on not much to speak of.By addressing issues such as these, psychologists could really help to clear up some messy debates and damaging misconceptions.Segal-Caspi, L., Roccas, S., and Sagiv, L. (2012). Don't Judge a Book by Its Cover, Revisited: Perceived and Reported Traits and Values of Attractive Women Psychological Science, 23 (10), 1112-1116 DOI: 10.1177/0956797612446349... Read more »
Segal-Caspi, L., Roccas, S., & Sagiv, L. (2012) Don't Judge a Book by Its Cover, Revisited: Perceived and Reported Traits and Values of Attractive Women. Psychological Science, 23(10), 1112-1116. DOI: 10.1177/0956797612446349
I love that cute is good for us. All this talk of cute, a website and some observations at home got me thinking this week. I recently saw this image posted on Facebook and I don’t mind admitting that it tugged at my emotions. Around the same day, I was watching my two year old toddler (an unpublished and independent kawaii survey reports the toddler is somewhat cute) interacting with my dogs (they are cute, no survey required).(source)The toddler is currently learning (slowly) that the world is not 100% about the toddler. This involves me frequently coaching the toddler’s interactions with other people and children (“yes it’s very sweet that you love your friend and that you’re giving them a big hug, but now you’ve actually crash-tackled them to the floor and they’re crying, it might be time to give them space”) and more recently in a similar way with the dogs.These home observations and website images got me thinking about how important my pets, and in particular, my dogs, were to me while growing up. (source)It got me wondering - why do so many of us have enduring psychological attachment to our childhood dogs? And do our childhood experiences stay with us as firmly held attitudes into adulthood? I plan to spend my next posts looking at some of the science surrounding children and dogs: the good, the bad and the ugly.Why are dogs good for children?The biophilia hypothesis suggests that people are instinctively attracted to animals and nature. It proposes that our relationship with them may contribute on an intimate biological level to our sense of fulfilment and identity. In our current busy lifestyles, often lived in industrialised city environments removed from ‘nature’ in its purest form, dogs and other companion animals offer opportunities for these ‘biophilic’ relationships. These nurturing relationships with animals are considered particularly important during early and middle childhood. Some research suggests that humans have a higher degree of attachment to dogs than we do to other companion animals; however, this may be a flaw in the way such studies have assessed attachment.Dogs may promote respect and compassion for animals and nature by offering a child valuable opportunity to experience and learn about animals and the ‘facts of life’. Dogs can assist children to learn about responsibility. They can encourage trust, self-belief as well as caring attitudes and behaviour. They may promote exercise and healthy development, offer social support and provide companionship, security, comfort. Dogs can be an important source of fun and have demonstrated they can act a... Read more »
O'Haire Marguerite. (2010) Companion animals and human health: Benefits, challenges, and the road ahead. Journal of Veterinary Behavior: Clinical Applications and Research, 5(5), 226-234. DOI: 10.1016/j.jveb.2010.02.002
Zasloff R.Lee. (1996) Measuring attachment to companion animals: a dog is not a cat is not a bird. Applied Animal Behaviour Science, 47(1-2), 43-48. DOI: 10.1016/0168-1591(95)01009-2
Holscher Bernd, Frye Christian, Wichmann H. -Erich, & Heinrich Joachim. (2002) Exposure to pets and allergies in children. Pediatric Allergy and Immunology, 13(5), 334-341. DOI: 10.1034/j.1399-3038.2002.02063.x
Anderson Katherine L., & Olson Myrna R. (2006) The value of a dog in a classroom of children with severe emotional disorders. Anthrozoos: A Multidisciplinary Journal of The Interactions of People , 19(1), 35-49. DOI: 10.2752/089279306785593919
Gee Nancy R., Harris Shelly L., & Johnson Kristina L. (2007) The Role of Therapy Dogs in Speed and Accuracy to Complete Motor Skills Tasks for Preschool Children. Anthrozoos: A Multidisciplinary Journal of The Interactions of People , 20(4), 375-386. DOI: 10.2752/089279307X245509
There's been loads of interest over the past few days in the idea that humans have been getting stupider for the past few millennia. That's according to Stanford's Gerald R. Crabtree - I would wager that if an average citizen from Athens of 1000 BC were to appear suddenly among us, he or she would be among the brightest and most intellectually alive of our colleagues and companions, with a good memory, a broad range of ideas, and a clear-sighted view of important issues. Furthermore, I would guess that he or she would be among the most emotionally stable of our friends and colleagues.OK. How so?Crabtree's argument in a nutshell:In Part I, he outlines the latest evidence showing that many thousands of genes contribute to human cognitive ability, and that because mutation rates are high (higher than previously believed), any given individual probably carries harmful variants of many of these genes. This is quite possibly true ,and interesting, but by itself it's nothing to do with declining IQ.In Part II, Crabtree says that during human evolution, all of these genes were under strong selection pressure because any human or proto-human who wasn't smart enough to hunt, fight and survive in the stone age environment, would get eaten by a predator or starve. However, after these hunter-gatherer tribes became settled farming communities (in say 6000 BC), they were no longer so vulnerable, so the less intellectually able could live... and breed... leading to ever-more unintelligence genes.Now, there's a lot of problems here. Many have said that this is all a bit like eugenics, and indeed it is, but that doesn't necessary mean it's wrong... no, it's wrong because the argument is flawed.For instance it's already been pointed out that even if it got easier to stay alive, that doesn't mean it's got easier to get laid lots and have lots of kids; and sexual selection is a powerful force in evolution, perhaps even stronger than survival, and it probably favours higher intelligence.However there are other problems.The idea that hunter-gatherers have especially hard lives is dubious. There's good evidence that life expectancy and health fell when hunter-gatherer societies settled down and got agriculture. Today, survival doesn't exert much of a selective pressure in most parts of the world but life expectancy and health stayed pretty dreadful (by modern standards) until at least the 19th century. You could indeed argue that 8,000-odd years of agriculture made us smarter than ever before, and that we're enjoying the benefits . In which case we'd be smarter than someone from 1000 BC, who only had 5,000 years or so.Crabtree does acknowledge that agriculture changed selection pressures. He suggests that it would have made it more important to be immune to the various diseases that emerged when our population density rose. But this isn't enough - for his argument to work, intelligence would also have needed to become less important with agriculture, and whether that's true is really not clear at all. Maybe it did. Maybe it didn't. There's a prejudice in modern culture against 'ignorant peasants' and 'dumb hicks', but farming is not easy.Even if we do grant that cognitive evolutionary pressures have eased since 1000 BC, it's not clear that this would make us 'less intelligent'. 'Intelligence' is not one thing. To simplify, it might be that there's a trade-off between 'book smarts' and 'street smarts', and that you used to need the latter to survive. A society in which everyone survives would then allow more people the luxury of being book-smart. I don't think Einstein or Newton would have been very good peasants.I think Crabtree's arguments are interesting but they're entirely speculative; there's just no hard evidence for the decline of intelligence over recent millennia. Since we can't go back in time and do IQ tests, there never will be, although he does suggest an experiment, using genetics, that might be able to check.But until then, as he puts it,in the meantime I’m going to have another beer and watch my favorite rerun of ‘Miami CSI’ (if I can figure out how to work the remote control).Crabtree, G. (2012). Our fragile intellect. Part II Trends in Genetics DOI: 10.1016/j.tig.2012.10.003 Crabtree, G. (2012). Our fragile intellect. Part I Trends in Genetics DOI: 10.1016/j.tig.2012.10.002... Read more »
Humans have a really poor sense of smell, as anyone who hasn’t been living under a rock surely knows. It just takes a brief glance at the many animals we keep as pets to realise that our olfactory senses are pretty shabby. The police rely on sniffer dogs to identify illicit substances, not specially trained … Continue reading »... Read more »
Pierron D, Cortés NG, Letellier T, & Grossman LI. (2012) Current relaxation of selection on the human genome: Tolerance of deleterious mutations on olfactory receptors. Molecular phylogenetics and evolution. PMID: 22906809
Myths and legends of Medieval Ireland describe this era as one of violence and conflict. The tales of Fionn mac Cumhaill and King Arthur describe roaming warbands and battles with mythological creatures. Numerous stories exist for kings and heroes who derive their fame from their ferocity and intelligence in conflict. The bioarchaeological evidence however supports … Continue reading »... Read more »
Geber, J. (2012) Comparative Study of Perimortem Weapon Trauma in Two Early Medieval Skeletal Populations (AD 400-1200) from Ireland. International Journal of Osteoarchaeology. DOI: 10.1002/oa.2281
The storied history of "Disruptive Mood Dysregulation Disorder (DMDD)", a controversial new child psychiatric disorder proposed for inclusion in the new DSM-5 manual, continues.If DSM-5 is officially published (it's due in 2013), kids will be deemed DMDD if they showsevere recurrent temper outbursts that are grossly out of proportion in intensity or duration to the situation.At least three times a week. Would giving that label be helpful?Pittsburg psychiatrists David Axelson and colleagues have just shown that the DMDD concept is deeply flawed. They took a large sample of kids assessed for emotional or behavior problems, and compared those who would meet the new DMDD criteria, to those who wouldn't."DMDD" turned out not to be correlated with anxiety or mood symptoms in either the child or their parents - rather unusual for a so-called 'Mood Dysregulation Disorder' which is found in the 'Depressive Disorder' section of the DSM-5.However, DMDD was correlated with - and in fact "could not be delimited from" - two existing disorders, "Conduct Disorder" and "Oppositional Defiant Disorder". It wasn't even a more severe form of those disorders, it was pretty much the same thing.So, DMDD seems to be nothing to do with mood, but instead covers a pattern of misbehavior which is already covered by not one but two labels already. Why add a misleadingly-named third?Well, the back-story is that in the past ten years, many American kids and even toddlers have got diagnosed with 'child bipolar disorder' - a disease considered extremely rare everywhere else. To stop this, the DSM-5 committee want to introduce DMDD as a replacement. This is the officially stated reason for introducing it. On the evidence of this paper and others it wouldn't even achieve this dubious goal.The possibility of just going to back to the days when psychiatrists didn't diagnose prepubescent children with bipolar (except in very rare cases) seems to not be on the table.Axelson D, et al (2012). Examining the proposed disruptive mood dysregulation disorder diagnosis in children in the Longitudinal Assessment of Manic Symptoms study. The Journal of Clinical Psychiatry, 73 (10), 1342-50 PMID: 23140653... Read more »
Axelson D, Findling RL, Fristad MA, Kowatch RA, Youngstrom EA, McCue Horwitz S, Arnold LE, Frazier TW, Ryan N, Demeter C.... (2012) Examining the proposed disruptive mood dysregulation disorder diagnosis in children in the Longitudinal Assessment of Manic Symptoms study. The Journal of clinical psychiatry, 73(10), 1342-50. PMID: 23140653
Neanderthals lived in Europe from ~400,000 years ago to ~28,000 years ago. During this time period the climate was difficult, with numerous ice ages and other dramatic climate shifts like Henrich events. Named after their discoverer, Hartmut Henrich, these are massive depositions of ice into the sea which can change direction of ocean currents. The … Continue reading »... Read more »
Wales N. (2012) Modeling Neanderthal clothing using ethnographic analogues. Journal of human evolution. PMID: 23084621
Two weeks ago my supervisor, Simon Kirby, gave a talk on some of the work that’s been going on in the LEC. Much of his talk focused on one of the key areas in language evolution research: the emergence of the basic design features that underpin language as a system of communication. He gave several [...]... Read more »
Kirby, S., Cornish, H., & Smith, K. (2008) Cumulative cultural evolution in the laboratory: An experimental approach to the origins of structure in human language. Proceedings of the National Academy of Sciences, 105(31), 10681-10686. DOI: 10.1073/pnas.0707835105
Ay, N., Flack, J., & Krakauer, D. (2007) Robustness and complexity co-constructed in multimodal signalling networks. Philosophical Transactions of the Royal Society B: Biological Sciences, 362(1479), 441-447. DOI: 10.1098/rstb.2006.1971
Eduardo G. Altmann, Janet B. Pierrehumbert, & Adilson E. Motter. (2010) Niche as a determinant of word fate in online groups. PLoS ONE 6(5), e19009 (2011). arXiv: 1009.3321v2
Whitacre, J. (2010) Degeneracy: a link between evolvability, robustness and complexity in biological systems. Theoretical Biology and Medical Modelling, 7(1), 6. DOI: 10.1186/1742-4682-7-6
Tuberculosis is one of the most infectious and fatal diseases worldwide. The spread of tuberculosis has been associated with social and biological factors, therefore determining its roots and tracing its history is important. Studies of historical cases of tuberculosis can help to understand the spread of the disease in modern populations. By looking at the … Continue reading »... Read more »
Nicklisch, N., Maixner, F., Ganslmeier, R., Friederich, S., Dresely, V., Meller, H., Zink, A., & Alt, K. (2012) Rib lesions in skeletons from early neolithic sites in Central Germany: On the trail of tuberculosis at the onset of agriculture. American Journal of Physical Anthropology, 149(3), 391-404. DOI: 10.1002/ajpa.22137
In the Shahnameh, Nahid's bad breath brings Alexander the Great to Greece. Al-Jahiz's claim that Persian men have sex with women with bad breath is undone. ... Read more »
Fischman, Stuart. (1997) The history of oral hygiene products: how far have we come in 6000 years?. Periodontology 2000, 15(1), 7-14. DOI: 10.1111/j.1600-0757.1997.tb00099.x
People talk about migraines on Twitter more on weekdays than weekends and holidays - and the peak time of day for the horrible headaches is 7 in the morning.The working-day effect on migraines has been reported before - perhaps a reflection of stress or, less charitably, people wanting a day off work... although some people suffer weekend migraines. Of the working week, Tuesdays saw the most migraines, while Fridays were the least bad. About 80% of Twitter migraine mentions came from women - which matches the fact that women are at higher risk.That's according to a little study just published that used a public database of tweets, timeu.se, that Neuroskeptic readers may remember.In fact, an author of this study said in an email to me that it was actually inspired by one of my posts... but I'm aware that telling you that, combined with the previous post, means I'm in danger of blowing my own trumpet or 'disappearing up my own arse' as we say in the UK. So rest assured that this will be the last such self-referential piece for at least... a day or two.Linnman, C., Maleki, N., Becerra, L., and Borsook, D. (2012). Migraine Tweets - What can online behavior tell us about disease? Cephalalgia DOI: 10.1177/0333102412465207... Read more »
Linnman, C., Maleki, N., Becerra, L., & Borsook, D. (2012) Migraine Tweets - What can online behavior tell us about disease?. Cephalalgia. DOI: 10.1177/0333102412465207
Does anyone still say "full of beans"? The phrase is supposed to describe someone who's upbeat and energetic. Maybe we can revive the expression by attaching it specifically to coffee beans, as in, "I just had a double-shot cappuccino and boy, oh boy am I full of beans!"
Caffeine lovers know the feeling of finishing a well-timed cup of coffee or tea: positive, alert, ready to go. (And maybe ready to go to the bathroom.) New research suggests that our brains also process language differently after having caffeine. We're quicker and more accurate at recognizing words—but only if those words have positive connotations.
Lars Kuchinke and Vanessa Lux, researchers at Ruhr University Bochum in Germany, studied the effect of caffeine on a word recognition challenge. To start, they recruited 66 subjects with a range of personal caffeine habits.
Leading up to the experiment, subjects abstained from coffee (and nicotine and alcohol) for at least 12 hours. Thirty minutes before the experiment started, each subject took a pill that contained either sugar or 200 mg of caffeine. That's the equivalent of 2 to 3 standard cups of coffee, or a bit less than 1 tall coffee at Starbucks. Subjects didn't know which pill they'd taken.
Then subjects sat facing a screen with their chins on a chin rest. While they focused on a spot in the center of the screen, words flashed briefly on one side or the other. Half the time, these were emotionally positive, negative, or neutral German words. The other half the time, they were nonsense words that looked similar to German ones. Subjects pressed a button indicating whether the word they'd just seen was real or not.
On the whole, people performed better on this task when the words flashed in front of their right eyes. This was expected, based on previous experiments and the fact that the right eye connects to the left hemisphere, the brain's language headquarters. What was more interesting was that on left-hemisphere trials, people who had taken a caffeine pill were significantly better at recognizing positive words than neutral or negative ones.
The researchers think the effect is down to dopamine. In addition to waking you up and making you quicker and more accurate at cognitive tasks, caffeine increases the activity of dopamine, a signaling molecule in the brain. (This may also be why caffeine drinkers say it improves their mood.)
Previous studies found that the brain is a little better at recognizing positive words (and happy faces) in general. Adding caffeine—and therefore dopamine—exaggerated this effect. Kuchinke and Lux think this is because dopamine interacts with the brain's language centers to make us quicker at processing positive words. They haven't yet studied how caffeine affects our understanding of outdated idioms.
Kuchinke, L., & Lux, V. (2012). Caffeine Improves Left Hemisphere Processing of Positive Words PLoS ONE, 7 (11) DOI: 10.1371/journal.pone.0048487
Image: Dan Barbus (Flickr)
... Read more »
Kuchinke, L., & Lux, V. (2012) Caffeine Improves Left Hemisphere Processing of Positive Words. PLoS ONE, 7(11). DOI: 10.1371/journal.pone.0048487
"We are covered in an ecological wonderland," declares Rob Dunn, a man with a strange idea of a wonderland. In the wild bacterial jungle that is our skin, Dunn has been studying an especially dark cave: the belly button. He's found out which microorganisms are the big game, which are the rare birds, and which ones may take up residence in your navel if you stop bathing.
Dunn is a biologist at North Carolina State University who studies the tiny life forms that share our personal space, from insects in our yards and houses to microbes on our bodies. The organisms we live with can affect our health, for better or worse. Yet researchers are only beginning to explore the various ecosystems we carry on ourselves. From our intestines to our faces to the bottoms of our feet, each of us holds a planet's worth of different habitats.
Out of all these bacterial habitats, the belly button is especially convenient to study. Everyone has one. Its shape and size don't change dramatically from person to person (among innies, anyway). And it's hard to scrub clean, making it a relatively undisturbed environment on the body. A national park, if you will.
The belly button also has crowd appeal, which is important for Dunn's citizen-science approach. He's interested in projects that involve unsqueamish members of the public. For his belly button research, Dunn recruited crowds at two 2011 events: One was Darwin Day at the Museum of Natural Sciences in Raleigh, North Carolina, and the other was the annual Science Online conference in Raleigh.
In total, 60 volunteers had their navels swabbed. Researchers extracted the bacterial DNA from each sample, sequenced it, and searched it for matches to particular species.
What the team found was diversity, and lots of it, as they report today in PLOS ONE. With a median of 67 different bacterial species per person, Dunn says the navel is at least as diverse as the other skin areas studied so far. That diversity varied widely; some people housed more than 3 times as many species in their belly buttons as others.
Out of the thousands of bacterial species the researchers found overall, the vast majority showed up in only a few people, or in just one person. Even though this habitat looks similar from one person to the next, we all have very different collections of rare critters running around in the undergrowth. No one bacterial species appeared in every belly button.
But there are common belly button denizens, too. On our umbilical safari, these are big obvious trees and loud monkeys that show up in most people's jungles. Eight species of bacteria were present in more than 70% of subjects. And wherever these species show up, they do so in large numbers. If you could dump the bacteria from everyone's belly buttons into one pile, members of the 8 king-of-the-jungle species would make up nearly half the heap.
Extending this group to the 23 most common bacterial species, the researchers looked at how the group's DNA compared to rarer bacteria. They found that the ruling bacteria were more closely related to each other than randomly selected groups of bacteria were—sort of a royal family. This suggests that the most common belly button bacteria share evolved traits that help them thrive in this environment.
The most surprising thing about the belly button bacteria, Dunn says, is their ultimate predictability. Even though thousands of species turned up in his study, he now knows which ones are most likely to live in someone's navel. "I expected that the common species would be far more random," he says. "But the truth was otherwise." There are only a few bacteria ruling the belly button jungle, and a diverse throng of others that make up their subjects. Dunn thinks we might be able to study what goes on in our skin's ecosystem by focusing on these few common bacteria.
Dunn hopes that eventually he'll be able to predict the specific bacteria living in someone's belly button based on their age, gender, habits, and history. "But I'll admit we are having an interesting struggle," he says. The research shows that people can be sorted into two or three "bacteriotypes," like blood types, based on the clusters of bacteria that inhabit their navels. But as to why a person is one type or another? "So far we can't explain what causes those differences," Dunn says. "It is a real mystery."
He's getting a little help in this area from one Science Online participant who claimed not to have showered or bathed in "several years." This subject's belly button swab turned up two species of archaea—single-celled organisms, entirely separate from bacteria, that often live in extreme environments. Until now, no one had found archaea on human skin.
This social non-conformer might represent the kinds of bacteria that our ancestors carried around. "Historically, no one washed very often," Dunn says. "This colleague of yours may be far more representative of how our bodies were for thousands, or even millions, of years than are most folks."
He adds, "That isn't saying I'm encouraging everyone to abandon washing."
Dunn suspects that belly button depth, too, might influence what species live there. But he's had a hard time studying this. "No one really wants to answer a question about the depth of their innie, no matter how anonymous we make the process," he says. However, his group's next study will look at a larger group of people, including outies.
Future safaris into our bodies' ecosystems might help scientists understand skin allergies and other health issues. Although belly button sampling is over for now, Dunn encourages people who want to get involved to join the mailing list at yourwildlife.org. He's currently looking at camel crickets in basements, ants in yards, and bacteria in bedrooms and kitchens.
"Armpits," Dunn adds—or perhaps threatens—"are also on the horizon."
Jiri Hulcr, Andrew M. Latimer, Jessica B. Henley, Nina R. Rountree, Noah Fierer, Andrea Lucky, Margaret D. Lowman, & Robert R. Dunn (2012). A Jungle in There: Bacteria in Belly Buttons are Highly Diverse, but Predictable PLOS ONE : 10.1371/journal.pone.0047712
Images: Copyright Belly Button Biodiversity.... Read more »
Jiri Hulcr, Andrew M. Latimer, Jessica B. Henley, Nina R. Rountree, Noah Fierer, Andrea Lucky, Margaret D. Lowman, & Robert R. Dunn. (2012) A Jungle in There: Bacteria in Belly Buttons are Highly Diverse, but Predictable. PLOS ONE. info:/10.1371/journal.pone.0047712
(Australian bushfires are big. Really big. source)Hey Julie,What an important topic to raise. It's so important that we stop to consider what animals are experiencing in times of natural disaster and 'rescue'. It got me thinking about a different kind of natural disaster that struck my local community in February 2009, the series of bushfires (wild fires) that came to be known in Australia as the Black Saturday bushfires. It was horrible. One of the formerly forested ridges in the 2009 bushfire zone (source)Extreme weather conditions, the lay of the land, an unexpected wind change and a series of fires that merged into one enormous front resulted in Australia's highest loss of life as a result of a bushfire. The fires were only 15km (9 miles) from my house and had the wind gone in a different direction it could easily have been my similarly bushy home area that was devastated. There were many, many, many people, pets, other animals and wildlife who were killed, injured and/or displaced by this huge and devastating event. But Julie, do you know what? Dogs helped. They really did. In so many special ways.A search and rescue dog and handler (source) Volunteer handlers with their search and rescue dogs helped to locate the remains of people who had died trying to defend or take shelter in their homes, enabling identification that would assist with closure for the victim's remaining families. We have evidence about how important the role of dogs and pets can be in our lives. Especially for children. The relationship children form with their pets has been shown to help modulate the effects of traumatic events like natural disasters. So keeping pets with families (or in a safe place that can be visited and where families know they are safe) is an important part of helping people cope in times of disaster. Just by being present, many dogs were acting as unwitting therapists. Offering the opportunity for calming behaviour - like patting, which has been shown to result in lower blood pressure and heart rate in the person patting the dog - when people really needed it. One of the most remarkable things that the injured and displaced dogs achieved was acting as a catalyst to community engagement and resilience. The nearest animal shelter to the area devastated was immediately inundated by displaced large animals, cats, dogs, other small pets and numerous wildlife. You can read their account from page 40 of the article in 'Animal Sheltering' magazine here. 'Happy' was treated for burns at the shelter & featured in the media (source) As the shelter had prepared for the possibility of a fire in the region, they were prepared to some degree. However, they found themselves immediately under pressure to find resources to house, feed and reunite hundreds of small and large animals with families who potentially (and very probably) had no homes left to return to. Within two days the shelter was inundated by offers of support from other vet clinics, community members, volunteers and people WANTING TO HELP THE DOGS (oh, OK, and the other animals!). ... Read more »
Yorke Jan. (2010) The significance of human–animal relationships as modulators of trauma effects in children: a developmental neurobiological perspective. Early Child Development and Care, 180(5), 559-570. DOI: 10.1080/03004430802181189
Vormbrock Julia K., & Grossberg John M. (1988) Cardiovascular effects of human-pet dog interactions. Journal of Behavioral Medicine, 11(5), 509-517. DOI: 10.1007/BF00844843
Cherry Katie E., Silva Jennifer L., & Marks Loren D. (2009) The Psychology Behind Helping and Prosocial Behaviors: An Examination from Intention to Action . Lifespan Perspectives on Natural Disasters, 219-240. DOI: 10.1007/978-1-4419-0393-8_11
Irvine Leslie. (2007) Ready or Not: Evacuating an Animal Shelter During a Mock Emergency. Anthrozoos: A Multidisciplinary Journal of The Interactions of People , 20(4), 355-364. DOI: 10.2752/089279307X245482
Many children spontaneously report memories of 'past lives'. For believers, this is evidence for reincarnation; for others, it's a psychological oddity.But what happens when they grow up?Icelandic psychologists Haraldsson and Abu-Izzedin looked into it. They took 28 adults, members of the Druze community of Lebanon. They'd all been interviewed about past life memories by the famous reincarnationist Professor Ian Stephenson in the 70s, back when they were just 3-9 years old.Did they still 'remember'? Most of them thought they did:Twelve of the 28 participants are sure that they still have clear memories of their past life, and an additional 12 believe that they still have some of their childhood memories, so 86% of our sample still report some memories of a past life... one man was not sure about the source of the memories, two remembered speaking of past life memories as a child, but do not have these memories now, and one thought she might only remember something of her past life because these memories were much talked about in her family.However - it turned out that they weren't always the same memories they'd originally reported.As children they reported on average 30 distinct memories of past lives. As adults they could only remember 8, but of those, only half matched the ones they'd talked about previously:This indicates that half of the statements remembered today are either fictional or distortions of the original childhood memories, or that the old lists of statements might have been incomplete. In other words, they probably suffered from a false memory of a false memory - the mind is weird. Despite this, past lives seemed more memorable than real early-childhood:We asked our participants what they remembered from their preschool years. We were surprised how little they remembered, and some could not remember anything. Our general impression is that past-life memories are better remembered into adult life than are normal memories from preschool years.There was no evidence that these people suffered from any particular psychological problems as a result of their experiences, but 21% did say that overall, they preferred their past lives to their real ones.Personally, I have a very vivid memory, not of a past life per se but rather of a very early stage in my own: I remember lying in my cot, unable to get out, rather bored, and waiting for my parents to get me up for the day.This may really be my earliest memory, but the more I've thought about it, the less likely it seems. Could I have known what time it was, and that my parents would eventually come, when I was unable to even stand up by myself?Maybe. But maybe it was just a later childhood dream about being a baby that seemed real. At that age, the line between dreams and reality is blurry as parents who've had to comfort a child after a nightmare will attest. I suspect this accounts for many of these 'past lives'.Haraldsson E, and Abu-Izzedin M (2012). Persistence of "past-life" memories in adults who, in their childhood, claimed memories of a past life. The Journal of nervous and mental disease, 200 (11), 985-9 PMID: 23124184... Read more »
Haraldsson E, & Abu-Izzedin M. (2012) Persistence of "past-life" memories in adults who, in their childhood, claimed memories of a past life. The Journal of nervous and mental disease, 200(11), 985-9. PMID: 23124184
Now that we are finally on the other side of one of the longest, most expensive political campaign seasons of United States history, we find ourselves with a new mixed-bag of leaders. Our nation’s decision-makers include career politicians and new freshman politicians; they include lawyers, military members, doctors, businessmen, farmers, ministers, educators, scientists, pilots, and entertainers; they include Protestants, Catholics, Jews, Quakers, Mormons, Buddhists and Muslims; they include white Americans, African Americans, Asian Americans, and Hispanic and Latino Americans; they include men and women; they include straight and gay people; and oh yeah, they include Republicans and Democrats. With so many differences that generate so many viewpoints, how will they ever find common ground to make the kind of decisions that will move our nation in a positive direction? Hey, Look guys! We make a peace sign! Image from Wikimedia. Research into group decision-making in social animals has shown that ants, fish, birds, and bees have all discovered strategies to make intelligent group decisions. If they can do it, we can do it, right? What can we learn from these critters about harnessing the knowledge in all of us to move our whole group in the best possible direction? We will explore these insights in this post, which is a mash-up of two previous posts. To see the originals, check out Can a Horde of Idiots Be a Genius? and Why This Horde of Idiots Is No Genius.Jean-Louis Deneubourg, a professor at the Free University of Brussels, and his colleagues tested the abilities of Argentine ants (a common dark-brown ant species) to collectively solve foraging problems. In one of these studies, the ants were provided with a bridge that connected the nest to a food source. This bridge split and fused in two places (like eyeglass frames), but at each split one branch was shorter than the other, resulting in a single shortest-path and multiple longer paths. After a few minutes, explorers crossed the bridge (by a meandering path) and discovered the food. This recruited foragers, each of which chose randomly between the short and the long branch at each split. Then suddenly, the foragers all started to prefer the shortest route. How did they do that?This figure from the Goss et al 1989 paper in Naturwissemschaften shows (a) the design of a single module, (b) ants scattered on the bridge after 4 minutes (I promise they’re there), and (c) ants mostly on the shortest path after 8 minutesYou can think of it this way: a single individual often tries to make decisions based on the uncertain information available to it. But if you have a group of individuals, they will likely each have information that differs somewhat from the information of others in the group. If they each make a decision based on their own information alone, they will likely result in a number of poor decisions and a few good ones. But if they can each base their decisions on the accumulation of all of the information of the group, they stand a much better chance of making a good decision. The more information accumulated, the more likely they are to make the best possible decision.In the case of the Argentine ant, the accumulated information takes the form of pheromone trails. Argentine ants lay pheromone trails both when leaving the nest and when returning to the nest. Ants that are lucky enough to take a shorter foraging route return to the nest sooner, increasing the pheromone concentration of the route each way. In this way, shorter routes develop more concentrated pheromone trails faster, which attract more ants, which further increase pheromone concentration of the shortest routes. In this way, an ant colony can make an intelligent decision (take the shortest foraging route) without any individual doing anything more intelligent than following a simple rule (follow the strongest pheromone signal).Home is where the heart is. Photo of a bee swarm by Tom SeeleyHoneybee colonies also solve complicated tasks with the use of communication. Tom Seeley at Cornell University and his colleagues have investigated the honeybee group decision-making process of finding a new home. When a colony outgrows their hive, hundreds of scouts will go in search of a suitable new home, preferably one that is high off the ground with a south-facing entrance and room to grow. During this time, the house-hunters will coalesce on a nearby branch while they search out and decide among new home options. This process can take anywhere from hours to days during which the colony is vulnerable and exposed. But they can’t be too hasty: choosing a new home that is too small or too exposed could be equally deadly. Although each swarm has a queen, she plays no role in making this life-or-death decision. Rather, this decision is made by a consensus among 300-500 scout bees that results after an intense “dance-debate”. If a scout finds a good candidate home, she returns to the colony and performs a waggle dance, a dance in which her body position and movements encode the directions to her site and her dancing vigor relates to how awesome she thinks the site is. Some scouts that see her dance may be persuaded to follow her directions and check out the site for themselves, and if impressed, may return to the hive and perform waggle dances too. Or they may follow another scout’s directions to a different site or even strike out on their own. Over time, scouts that are less enthusiastic about their discovered site stop dancing, in part discouraged by dancers for other sites that bump heads with them and beep at them in disagreement. Eventually, the majority of the dancing scouts are all dancing the same vigorous dance. But interestingly, few scouts ever visit more than one site. Better sites simply receive more vigorous “dance-votes” and then attract more scouts to do the same. Like ants in search of a foraging path, the intensity of the collective signal drives the group towards the best decision. Once a quorum is reached, the honeybees leave their branch as a single united swarm and move into their new home, which is almost always the best site. ... Read more »
List, C., Elsholtz, C., & Seeley, T. (2009) Independence and interdependence in collective decision making: an agent-based model of nest-site choice by honeybee swarms. Philosophical Transactions of the Royal Society B: Biological Sciences, 364(1518), 755-762. DOI: 10.1098/rstb.2008.0277
Seeley, T., Visscher, P., Schlegel, T., Hogan, P., Franks, N., & Marshall, J. (2011) Stop Signals Provide Cross Inhibition in Collective Decision-Making by Honeybee Swarms. Science, 335(6064), 108-111. DOI: 10.1126/science.1210361
Dell'Ariccia, G., Dell'Omo, G., Wolfer, D., & Lipp, H. (2008) Flock flying improves pigeons' homing: GPS track analysis of individual flyers versus small groups. Animal Behaviour, 76(4), 1165-1172. DOI: 10.1016/j.anbehav.2008.05.022
Australopithecus afarensis is a bipedal human ancestor which lived in Africa from 3.9 – 2.9 million years ago. It’s particularly notable for being the first hominin to have a human-like foot, having replaced the chimp-like opposable toe of its ancestor Ardipithecus ramidus (who lived 4.4 million years ago) with a forward-facing human-esque toe. Although Ar. … Continue reading »... Read more »
Green, D., & Alemseged, Z. (2012) Australopithecus afarensis Scapular Ontogeny, Function, and the Role of Climbing in Human Evolution. Science, 338(6106), 514-517. DOI: 10.1126/science.1227123
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