At the end of the last ice age modern humans were migrating out of Africa, Neanderthals roamed Europe, and new research has shown that a previously unknown population of ancient humans lived in Asia. All that remains of this mysterious group is a section of finger bone and a wisdom tooth. The group has been named the Denisovans after Denisova Cave in Siberia where the tooth and bone segment were found. A few months ago researchers completed an analysis of mitochondrial DNA from the finger bone and concluded that it had belonged to a child who lived about 40,000 years ago and was genetically different from both modern humans and Neanderthals.... Read more »
Reich, D., Green, R., Kircher, M., Krause, J., Patterson, N., Durand, E., Viola, B., Briggs, A., Stenzel, U., Johnson, P.... (2010) Genetic history of an archaic hominin group from Denisova Cave in Siberia. Nature, 468(7327), 1053-1060. DOI: 10.1038/nature09710
Habituation: a necessary method for primate research, but is it ethical from a biocentric perspective?... Read more »
Doran-Sheehy, D., Derby, A., Greer, D., & Mongo, P. (2007) Habituation of western gorillas: the process and factors that influence it. American Journal of Primatology, 69(12), 1354-1369. DOI: 10.1002/ajp.20442
by Rita Handrich in The Jury Room
I remember being fascinated by Truman Capote’s In Cold Blood. And during my maternity leave after my first child was born, I watched most of the Jeffrey Dahmer trials on CNN aware of the irony inherent in rocking my sleeping newborn while tracking the testimony of Park Dietz. So, naturally, when I saw the new [...]
Related posts:Men married to rich women are more likely to cheat
Keep your eye on this one: A Depravity Scale
New research on men: What do we know now?
... Read more »
Vicary, A., & Fraley, R. (2010) Captured by True Crime: Why Are Women Drawn to Tales of Rape, Murder, and Serial Killers?. Social Psychological and Personality Science, 1(1), 81-86. DOI: 10.1177/1948550609355486
Remember the 90s, when No Fear stuff was cool, and when people still said "cool"?Well, a new paper has brought No Fear back, by reporting on a woman who has no fear - due to brain damage. The article, The Human Amygdala and the Induction and Experience of Fear, is brought to you by a list of neuroscientists including big names such as Antonio Damasio (of Phineas Gage fame).The basic story is nice and simple. There's a woman, SM, who lacks a part of the brain called the amygdala. They found that she can't feel fear. Therefore, it's reasonable to assume that the amygdala's required for fear. But there's a bit more to it than that...The amygdala is a small nugget of the brain nestled in the medial temporal lobe. The name comes from the Greek for "almond" because apparently it looks like one, though I can't say I've noticed the resemblance myself.What does it do? Good question. There are two main schools of thought. Some think that the amygdala is responsible for the emotion of fear, while others argue that its role is much broader and that it's responsible for measuring the "salience" or importance of stimuli, which covers fear but also much else.That's where this new paper comes in, with the patient SM. She's not a new patient: she's been studied for years, and many papers have been published about her. I wonder if her acronym doesn't stand for "Scientific Motherlode"?She's one of the very few living cases of Urbach-Wiethe disease, an extremely rare genetic disorder which causes selective degeneration of the amygdala as well as other symptoms such as skin problems.Previous studies on SM mostly focussed on specific aspects of her neurological function e.g. memory, perception and so on. However there have been a few studies of her "everyday" experiences and personality. Thus we learned that:Two experienced clinical psychologists conducted "blind" interviews of SM (the psychologists were not provided any background information)... Both reached the conclusion that SM expressed a normal range of affect and emotion... However, they both noted that SM was remarkably dispassionate when relating highly emotional and traumatic life experiences... To the psychologists, SM came across as a "survivor", as being "resilient" and even "heroic".These observations were based on interviews under normal conditions; what would happen if you actually went out of your way to try and scare her? So they did.First, they took her to an exotic pet store and got her to meet various snakes and spiders. She was perfectly happy picking up the various critters and had to be prevented from getting too closely acquainted with the more dangerous ones.What's fascinating is that before she went to the store, she claimed to hate snakes and spiders! Why? Before she developed Urbach-Wiethe disease, she had a normal childhood up to about the age of 10. Presumably she used to be afraid of them, and just never updated this belief, a great example of how our own narratives about our feelings can clash with our real feelings.They subsequently confirmed that SM was fearless by taking her to a "haunted asylum" (check it out, even the website is scary) and showing her various horror movie clips, as well as through interviews with herself and her son. They also describe an incredible incident from several years ago: SM was walking home late at night when she sawA man, whom SM described as looking “drugged-out.” As she walked past the park, the man called out and motioned for her to come over. SM made her way to the park bench. As she got within arm’s reach of the man, he suddenly stood up, pulled her down to the bench by her shirt, stuck a knife to her throat, and exclaimed, “I’m going to cut you, bitch!”SM claims that she remained calm, did not panic, and did not feel afraid. In the distance she could hear the church choir singing. She looked at the man and confidently replied, “If you’re going to kill me, you’re gonna have to go through my God’s angels first.” The man suddenly let her go. SM reports “walking” back to her home. On the following day, she walked past the same park again. There were no signs of avoidance behavior and no feelings of fear.All this suggests that the amygdala has a key role in the experience of fear, as opposed to other emotions: there is no evidence to suggest that SM lacks the ability to experience happiness or sadness in the same way.So this is an interesting contribution to the debate on the role of the amygdala, although we really need someone to do equally detailed studies on other Urbach-Wiethe patients to make sure that it's not just that SM happens to be unusually brave for some other reason. What's doubly interesting, though, is that Ralph Adolphs, one of the authors, has previously argued against the view of the amygdala as a "fear center".Links: I've previously written about the psychology of horror movies and I've reviewed quite a lot of them too.Justin S. Feinstein, Ralph Adolphs, Antonio Damasio,, & and Daniel Tranel (2010). The Human Amygdala and the Induction and Experience of Fear Current Biology... Read more »
Justin S. Feinstein, Ralph Adolphs, Antonio Damasio,, & and Daniel Tranel1. (2010) The Human Amygdala and the Induction and Experience of Fear. Current Biology. info:/
The effect of the eruption of Sunset Crater Volcano on the prehistoric population of northern Arizona has long been a topic of interest to archaeologists. As I’ve mentioned recently, in the 1930s and 1940s Harold Colton of the Museum of Northern Arizona in Flagstaff came up with a theory to explain the settlement dynamics of [...]... Read more »
ORT, M., ELSON, M., ANDERSON, K., DUFFIELD, W., & SAMPLES, T. (2008) Variable effects of cinder-cone eruptions on prehistoric agrarian human populations in the American southwest. Journal of Volcanology and Geothermal Research, 176(3), 363-376. DOI: 10.1016/j.jvolgeores.2008.01.031
Wupatki is a very dry place even by the standards of the Southwest, with annual precipitation averaging about 8 inches. Human habitation in such an arid landscape is therefore highly dependent on capturing as much available moisture as possible. It appears that the prehistoric inhabitants took advantage of the volcanic ash laid down over the [...]... Read more »
This week's theme is epistemological unease in the sciences: Complaints in a number of disciplines that studies didn't really find the effects they're reporting. One reason for these worries is that many studies nowadays are never repeated. So today I'm going to consciously and rationally resist ...Read More
... Read more »
Phillips, D., Kanter, E., Bednarczyk, B., & Tastad, P. (1991) Importance of the Lay Press in the Transmission of Medical Knowledge to the Scientific Community. New England Journal of Medicine, 325(16), 1180-1183. DOI: 10.1056/NEJM199110173251620
Markey, P., & Markey, C. (2010) Changes in pornography-seeking behaviors following political elections: an examination of the challenge hypothesis. Evolution and Human Behavior, 31(6), 442-446. DOI: 10.1016/j.evolhumbehav.2010.06.004
The paper by Glenn Davis Stone and Christian Downum that I mentioned in the last post, which evaluated the archaeological record of the Wupatki area of northern Arizona in the light of Ester Boserup‘s theory of agricultural intensification, was based largely on the data from an extensive archaeological survey of Wupatki National Monument done by [...]... Read more »
Sullivan, A., & Downum, C. (1991) Aridity, activity, and volcanic ash agriculture: A study of short-term prehistoric cultural-ecological dynamics. World Archaeology, 22(3), 271-287. DOI: 10.1080/00438243.1991.9980146
Scientists have often looked to nature in the quest for new drugs to treat everything from cancer to infectious diseases, and they’ve found effective drugs in unexpected places – sea sponges, the bark of the Pacific yew tree, a throat swab from a chicken. But archaeologist Patrick McGovern and an interdisciplinary group of researchers at the University of Pennsylvania are using a different approach: they’re looking to the past in search of new drugs.... Read more »
McGovern, . (2010) Anticancer activity of botanical compounds in ancient fermented beverages (Review). International Journal of Oncology, 37(1). DOI: 10.3892/ijo_00000647
It's hard to imagine that knowledge could be lost today. Technology seems to have put the ability to know almost everything within our grasp. So when researchers announced that they had "found" a previously unknown Peruvian language earlier this year, it was strangely tantalizing. Here was knowledge that we couldn't Google. We could plumb the archives and look for clues that might offer answers, but true understanding would not be easily attainable. And in all likelihood, we would have to resign ourselves to not knowing.
The back side of the Magdalena document shows
translations for numbers from Spanish to a lost language.
Photo by Jeffrey Quilter.
In a public-friendly article, Jeffrey Quilter and colleagues (2010) announced in September that they had uncovered a remarkable find at an archaeological dig in Northern Peru: It wasn't a funerary mask or ornate pottery or even a mummy, but a page. A letter actually, dating to 17th-century and detailing a minor trade event in the church complex where it was found. It is an interesting artifact by itself that could offer a glimpse into the life of the colonial community being uncovered. However, on the back of the letter someone had scribbled a number list in a previously unknown language, making the page more than just a record of church concerns. Though the list is short, it is enough to help researchers understand that they have in their hands the details of a number system that has not been previously recorded. As the researchers note, the history of the document itself—how and why it was created and then discarded—is tied to larger aspects of Peruvian history. And this history can help us understand the linguistic dynamics of cultural contact—which may be extended in some ways to the digital age.
Many People, Many Languages
The site of Santa Maria Magdalena de Cao is on the North Coast of Peru and provides a glimpse at life in a colonial town. Occupied from the late 16th- to the late 18th-century, the town was a redducion, a Spanish-style town where conquered populations were forced to live together under colonial rule. These towns naturally would have been sites of “mixing”: over time, the meeting of different cultural and linguistic backgrounds would have yielded to new forms of cultural identity with a tendency toward that of the conqueror.
It is perhaps wise to pause here for a moment and note that some form of this sort of “mixing” had been going on well before the Spanish arrived as a colonial presence in South America, particularly at the hands of the Inka (Inca):A highly complex linguistic and cultural landscape that had been created through millennia of human interactions was still present in the mid-16th-century era of the Spanish intrusion. The palimpsest of societies and tongues owing to historical processes of the rise and fall of empires and movements of people was augmented by a variety of specific cultural practices as well, such as the placing of colonies forcibly, as under Inka imperial policy (Quilter et. al. 2010: 361).Indeed, there may have been many indigenous languages in Peru in prehistory that may have been absorbed after Inkan conquests. For example, between 100 and 800 CE, the North Coast of Peru was home to a culture known as the Moche or Mochica. Given the breadth of the region it is likely more than one language was spoken, but this is not definitively known. The archaeological record tells us that Northern and Southern regions of the Moche subsequently developed into the Lambayeque and Chimu respectively, and the Chimu appears to have conquered or absorbed the former, and gone on to become a rival to the Inka empire. However, contact with the Inka left traces on the Chimu society:There is substantial evidence to suggest that the Inka actively worked to co-opt or coerce local elites into Inka cultural practices as a means of political control, and it is well known that they also brought the sons of local leaders to Cuzco for training in such practices (Quilter et. al. 2010: 361).For this coercion to be effective, a common language would be of immense importance. To this end, the Inka helped spread the Quechua language family, a dialect that is widely used throughout the Andes, though they themselves may have spoken another language. The use of Cuzco Quechua would have helped solidify the goals of empire.
Learning to Count
Similar linguistic practices were employed by colonial powers via the Catholic Church to establish the state’s authority. In fact, the Spanish helped spread some version of Quechua themselves to teach the Gospel, and consequently impose Spanish law and order on the local people. Church records suggest that there were at least two but possibly three distinct languages spoken on the North Coast: Quingnam, the language of the Chimu monarchs, Mochica, a dialect spoken along the coast, and Pescadora, the language of the North Coast fisherfolk. It is likely that the fisherfolk spoke a distinct language in keeping with the socioeconomic organization in the region. Within these three languages, there would have been numerous dialects, so it is no surprise that the Church would have worked to reduce the number of languages that they would have had to work with.
The document suggests an attempt to learn the number system of a regional dialect. The author wrote out the Spanish names for the numbers 1 – 3, and the Arabic numerals for 4 – 10, 21, 30, 100 and 200, giving us the following:uno-chari
21. maribencor chari tayac
30 apar becor
100 chari pachac
200 mari pachac
It clearly lays out the system’s combinatory rules, and suggests that by learning this sequence, the rest of the sequence could be filled in. Interestingly, pachac appears to have been borrowed from Quechuan, but the list does not yield any other real linguistic clues about origins. The other numbers are unique and distinct, and numbers themselves function as narrow, repetitive systems within languages.
But we know enough to know what it is not. That is to say, Mochica survived into the 19th-century, and we have word lists that reveal no similarities to the found list of numerals. Records remain also from the Inka, allowing for comparisons and showing no similarities. No trace of the Quingnan and Pecadora languages remain, so they cannot be definitively ruled out. But the one potential connection to Quechuan suggests some point of contact with the larger language family.
There is a possibility that the numbers may be part of a trader’s language within Pescadora. Missionary records make reference to two Pescadora languages, with the possibility of one being a pidgin: a simplified trade language modeled after higher-status language(s), with shared grammatical and semantic features taken from the borrower’s native tongue (365). Pidgins are common in communities with high mobility that are engaged in trade because they help with communication between the two groups and facilitate commerce. The letter on which the numbers were scribbled reference a commercial transaction, perhaps the number system was a note for a potential transaction of its own. But without additional information, this is pure speculation—fun to imagine, but speculation nonetheless.
Language Lost Today?
Lost languages are not ... Read more »
Quilter, J., Zender, M., Spalding, K., Jordán, R., Mora, C., & Murga, J. (2010) RESEARCH ARTICLES: Traces of a Lost Language and Number System Discovered on the North Coast of Peru. American Anthropologist, 112(3), 357-369. DOI: 10.1111/j.1548-1433.2010.01245.x
In the age of 500,000 SNP studies of genetic variation across dozens of populations obviously we’re a bit beyond lists of ABO blood frequencies. There’s no real way that a conventional human is going to be able to discern patterns of correlated allele frequency variations which point to between population genetic differences on this [...]... Read more »
Olivier François, Mathias Currat, Nicolas Ray, Eunjung Han, Laurent Excoffier, & John Novembre. (2010) Principal Component Analysis under Population Genetic Models of Range Expansion and Admixture. Mol Biol Evol . info:/
The paper I discussed earlier on the connection between plow-based agriculture and highly inegalitarian gender roles was based on a theory proposed by Ester Boserup. Boserup was a Danish economist who had a lot of interesting ideas about the relationship between population growth and agricultural intensification. She’s best known for arguing that intensification of agricultural [...]... Read more »
Stone, G., & Downum, C. (1999) Non-Boserupian Ecology and Agricultural Risk: Ethnic Politics and Land Control in the Arid Southwest. American Anthropologist, 101(1), 113-128. DOI: 10.1525/aa.1922.214.171.124
Credit: Scott Hampson
It's no secret that the Internet is a black hole when it comes to time. Fifteen minutes on Twitter spirals into an hour or two of witty banter. A quick stop on Facebook to read statuses or water crops becomes three hours looking at photos from someone's vacation or wedding. (And email? Fuggedaboutit!) But it's easy to be online—simple and almost instantaneous access to all your friends and connections, and none of them need to know you're in your pajamas. And you can reinvent yourself online, which is handy for those of us with histories of awkwardness (or present awkwardness for that matter). The Internet is always with us. It's in our pockets and bags on our phones, and wherever free WiFi can be found for those with netbooks, tablets, and laptops, which provides us with a handy way to escape uncomfortable situations—how many of your with smart phones have checked (or pretended to check) email, Facebook, or Twitter at a party where the conversation wasn't going quite right?
For adolescents and teens in particular unmonitored access can quickly lead to problematic Internet use (PIU), which in turn can develop into Internet addiction. In a relatively small study, researchers Milani, Osaualdella, and Di Blasio (2009) discuss the ways online social interactions can help adolescents develop a sense of belonging, particularly in instances of self-imposed or group-driven social isolation. Online social interactions in these cases offer simple ways of restoring a sense of normalcy:the association between loneliness and the negative consequences of Internet use is effectively mediated by the preference for online social interactions, which allows individuals with particular problems in this are to perceive themselves as more secure and more at ease than in traditional face-to-face interactions [Caplan 2007 by Milani et. al. 2009] (681).Using a sample of Italian students, Milani and colleagues demonstrated the potential relationship between PIU, quality of interpersonal relationships, coping skills, and capacity to internalize/externalize social norms. To this end, they employed the following tools:an Italian-version Internet Addiction Test (IAT) (cutoff score for PIU is 50, and effective dependence is 80);
Test of Interpersonal Relationships (TRI), which measures the quality of relationships;
an Italian-version Children's Coping Strategies Checklist (CCSC), which measures coping skills;
and a Questionnaire for the Recording of Internet Use Habits, which measured participants' browsing habits.
Approximately, 37% (of a sample population of 98) participants had an IAT score of 50 or higher. The small sample size for this study is a bit problematic, but the researchers believe that their data demonstrates that adolescents with PIU have less quality relationships in their lives: These individuals scored higher on sub-tests within the CCSC for avoidance behaviors as a coping strategy. Avoidance behaviors can be a predictor for PIU as the authors report that there is a connection between Internet dependency and certain personality traits, such as preference for solitary activities and low social openness (2009: 681).This, adolescents with poor interpersonal relationships and a predisposition for adopting an avoidance coping strategy are at a greater risk of developing PIU (683).The bottom line is that socializing online cannot substitute for real life connections, particularly for adolescents who are still learning and developing strategies for coping with real world situations and relationships. This is not necessarily new news, but as the DSM-V considers whether to include IAD, studies such as this confirm the impact of digital technologies on our lives, and invite a closer look as potential long-term effects.
Cited:Milani, L., Osualdella, D., & Di Blasio, P. (2009). Quality of Interpersonal Relationships and Problematic Internet Use in Adolescence CyberPsychology & Behavior, 12 (6), 681-684 DOI: 10.1089/cpb.2009.0071
... Read more »
Milani, L., Osualdella, D., & Di Blasio, P. (2009) Quality of Interpersonal Relationships and Problematic Internet Use in Adolescence. CyberPsychology , 12(6), 681-684. DOI: 10.1089/cpb.2009.0071
Two years ago, a paper was published in Nature describing the function of the oldest known scientific computer, a device built in Greece around 100 BCE. ... Read more »
Ole Magga, Norwegian politician
On this blog I regularly get questions about the Sami (Lapp*). That’s because I often talk about Finnish genetics, have readers such as Clark who are of part-Sami origin, and, the provenance and character of the Sami speak to broader questions about the emergence of the modern European gene pool. More precisely [...]... Read more »
Maki-Torkko, Elina, Aikio, Pekka, Sorri, Martti, Huentelman, Matthew J, & Camp, Guy Van. (2010) A genome-wide analysis of population structure in the Finnish Saami with implications for genetic association studies. European Journal of Human Genetics. info:/10.1038/ejhg.2010.179
This is the first in a series of blog posts about my experiences undertaking an ongoing research project. In this series I will be detailing some of the methodological challenges I encounter as well as the strategies I adopt to … Continue reading →... Read more »
Maher, J. C. (2005) Metroethnicity, language and the principle of cool. International Journal of the Sociology of Languages, 83. info:/
Human and bonobo ape hands. © SPL
New Yorkers are hand talkers—we often use gestures to add emphasis to our conversations. Whether we're pointing to direct tourists, or waving to demonstrate our exasperation with traffic, drivers, or pedestrians, or trying to interject (New Yorkers don't interrupt!) we're gesticulating. We're not the only ones to do this, of course, but in my experience we do tend to employ this element of communication fairly frequently.
The role of gestures in communication has been on my mind recently because my goddaughter is just beginning to communicate beyond crying and laughing. She recently celebrated her first birthday, and she's begun to speak her first words. ("Shoe!" is a favorite even when it is in fact a sock, as is "No!" and "Elmo!" I'm working on "Dinosaur" but that one is slow going.) It's extremely exciting. I find it really interesting that she points with increasing frequency to emphasize her exclamations—Elmo isn't just a word, he's a recognizable part of her world, from the decorations that were a part of her birthday celebration to her stuffed muppet that laughs when shaken. Her gestures help her bridge a communication gap.
Gestures are an integral part of language. Arbib, Liebal, and Pika (2008) believe that gestures, via pantomime and protosigns, may have played a large role in the emergence of vocalization (protospeech) leading to the development of protolanguage (1054). Their hypothesis is based on the structure of the brain, specifically a mirroring of structures in the brain: near Broca's area, a region of the brain said to be involved in language production, is a region "activated for both grasping and observation of grasping" (1053). The proximity of a grasping region to a language region is intriguing. Individuals who have suffered damage to Broca's area have difficulties with language production. They can often understand others perfectly, but they have difficulty responding in all but the simplest of ways. Arbib and colleagues suggest that because damage to Broca's area also impedes the emergence of signed languages as well, the region should be understood in relation to multimodal language processes and not just vocalization. They believe this creates a strong case for understanding the place of gestures in the evolution of language.
Gestures are common to many species of monkeys and apes, however, usage seems to vary between captive and wild groups. For example:Siamangs have demonstrated at least 20 different tactile and visual gestures in captive groups (1).
Approximately 10 different gestures have been reported for wild orangutans and 30 have been described for captive groups,
Captive gorillas use at least 30 different tactile, visual, and auditory gestures—but little is known about their gestures in the wild.
Chimpanzees also have a large repertoire of gestures in captivity, with about a dozen having been recorded in the wile.
These numbers refer to entire populations. Within the group, an individual's use of gestures depends on age, sex, and rank. There are also group-specific gestures, such as:"Offer arm with food pieces" in orangutans, "arm shake" in gorillas, and "punch" in bonobos are examples reported from captive groups, while "leaf clipping" and "grooming hand clasp" are described as group-specific gestures in wild chimpanzees (1057). Small, stable groups tend to have less intra-group variability than large, socially complex groups. Larger groups tend to have greater variability between members, requiring greater variety and variability in communicative means.
Adult male gorilla (Gorilla gorilla)
with a two-year-old juvenile. © SPL
The higher number of observed gestures in captive groups also hints at an ability to learn (2). Basic forms of gestures and communication seem to be genetically preprogrammed (e.g., "chest beat" has been reported for gorillas that had never seen other gorillas). A process called ontogenetic ritualization may explain how gestures are learned—"a communicative signal is created by two individuals shaping each other's behaviors in repeated instances of an interaction over time," allowing behaviors to become signals (Arbib, Liebal, and Pika 2008: 1058). The example the authors provide is the "arm rise": a stylized gesture that chimpanzees use to signal that they are about to hit each other and initiate rough-and-tumble play (3). Gestures are also used referentially, indicating that they can be intentionally deployed to manipulate or direct the actions of others. Captive chimpanzees, for example, use the "directed scratch": a loud and/or exaggerated scratching motion to indicate where the grooming partner should focus attention (1057).
This discussion supports the criteria by which gestures are judged to be language:whether they are used intentionally or are side effects of emotional states
whether they are flexible
whether they have an inherent meaning or whether the meaning is conveyed by social context
whether they are inherited or learned
whether they are used referentially
These criteria allow us to compare gestural communication between apes and humans. Referential gestures (or triadic gestures) begin to appear in prelinguistic children at around the age of 12 months. But even before this stage, children may demonstrate dyadic gestures, which direct attention to the actor. Chimpanzee infants begin to employ gestures around the age of 9 to 12.5 months, however, with few exceptions the majority of gestures used are dyadic. Attempts to teach apes to speak have not been very successful. Kanzi, a bonobo who spent the early years of his life observing his mother while she used a computerized keyboard, remains a rare success story. He learned many of the symbols (lexigrams) that his mother had not likely through exposure, which is similar to the way in which children learn to speak. They pick up on patterns from the behaviors of adults around them. His ability to understand English compares to a 2-year-old human child: He is able to combine two or three lexigrams or a lexigram and gesture, and order items (Arbib, Liebal, and Pika 2008: 1060).
His success aside, apes generally acquire symbols at a much slower rate when ... Read more »
Arbib, M., Liebal, K., & Pika, S. (2008) Primate Vocalization, Gesture, and the Evolution of Human Language. Current Anthropology, 49(6), 1053-1076. DOI: 10.1086/593015
A new study has provided the strongest evidence yet that the rate of autism in children rises with the father's age: Advancing paternal age and risk of autism. But questions remain.The association between old fathers and autism has been known for many years, and the most popular explanation has been genetic: sperm from older men are more likely to have accumulated DNA damage, which might lead to autism.As I've said before, this might explain some other puzzling things such as the fact that it's more common in the wealthy; it might even explain any recent increases in the prevalence of autism, if people nowadays are waiting longer to have kids.But there are other possibilities. It might be that the fathers of autistic people tend to have mild autistic symptoms themselves (which they do), and this makes them likely to delay having children, because they're socially anxious and so take longer to get married, or whatever. It's not implausible.The new study aimed to control for this, by looking at parents who had two or more children, at least one of them with autism, and at least one without it. Even within such families, the autistic children tended to have older fathers when they were born - that is to say, they were born later. See the graphs below for details. This seems to rule out explanations based on the characteristics of the parents.However, there's another objection, the "experienced parent" theory. Maybe if parents have already had one neurotypical child, they're better at spotting the symptoms of autism in subsequent children, by comparison with the first one.The authors tried to account for this as well, by controlling for the birth-order ("parity") of the kids. They also controlled for the mother's age amongst several other factors such as year of birth and history of mental illness in the parents. The results were still highly significant: older fathers meant a higher risk of autism. As if that wasn't enough, they also did a meta-analysis of all the previous studies and confirmed the same thing.So overall, this is a very strong study, but there's a catch. The study population included over a million children (1,075,588) born in Sweden between 1983 and 1992. Of these, there was a total of 883 diagnosed cases of autism. That's a rate of 0.08%.The most recent estimates of autism prevalence in Britain have put the figure at somewhere in the region of between 1% and 2% e.g. Baird et al (2006) and Baron-Cohen et al (2009) with American studies, using slightly different methods, generally coming in just below 1%. So the Swedish figure is more than 10 times lower than modern estimates. Whether this reflects different criteria for diagnosis, national differences, or increased prevalence over time, is debatable but it does raise the question of whether these findings still apply today.The only way to know for sure would be to do a randomized controlled trial - get half your volunteer men to wait 10 years before having children - but I don't think that's going to happen any time soon...Hultman CM, Sandin S, Levine SZ, Lichtenstein P, & Reichenberg A (2010). Advancing paternal age and risk of autism: new evidence from a population-based study and a meta-analysis of epidemiological studies. Molecular psychiatry PMID: 21116277... Read more »
Hultman CM, Sandin S, Levine SZ, Lichtenstein P, & Reichenberg A. (2010) Advancing paternal age and risk of autism: new evidence from a population-based study and a meta-analysis of epidemiological studies. Molecular psychiatry. PMID: 21116277
"Two chimps had been shut out of their shelter by mistake during a cold rain storm. They were standing dejeted, water streaming down their shivering bodies, when Professor Köhler chanced to pass." Upon opening the door for the two chimps, Dr. James Leuba recounts, "instead of scampering in without more ado, as many a child would have done, each of them delayed entering the warm shelter long enough to throw its arms around his benefactor in a frenzy of satisfaction."
"Chimpanzees," primatologist Frans de Waal points out, "do not normally hug their caretakers for no reason." It's a compelling image, isn't it? The idea that at least some animals might be capable of feeling and communicating gratitude? If we wish to make an argument that some animals possess at least some sort of proto-gratitude, or the cognitive building blocks required for them to feel and express gratitude, we first have to decide what gratitude really means.
Impala are large antelopes native to Africa that groom eachother. Grooming exchanges among African impala are usually unsolicited: one individual grooms the neck of a second individual, and then the second individual returns the favor, and grooms the first individual for an equivalent amoung of time. Hart and Hart suggested that this mutual grooming behavior serves to remove ticks from parts of the body that an individual can't reach itself.
Vampire bats, as you might expect, survive only on blood, and most feed at least once every three days. And while adult vampire bats regularly miss meals, they need not worry, as other individuals will regurgitate blood to feed them.
While the impala and vampire bat examples are interesting, they can be explained by much a simpler mechanism than gratitude: symmetry-based reciprocity. That is, "if members of a species preferentially direct favors to close associates, the distribution of favors will automatically be reciprocal due to the symmetrical nature of association." In other words, the mutual back-scratching of the impala and blood-vomiting of the vampire bat could simply be correlational: individuals who hang out together will tend to engage in reciprocal interactions, but only because they tend to hang out together. These sorts of interactions do not require any sophisticated mental computation for directing repayment only at certain individuals or for keeping track of services received and rendered over time.
Perhaps it seems like your adopted dog or cat pays special attention to you, perhaps in gratitude for his or her rescue? Bonnie and de Waal write:
Even though we have all heard of (and the authors have personal experience with) pets adopted from a miserable stray existence into the comfort of modern homes, it is possible to tell if their greater-than-average appreciation (e.g. tail wagging, purring) of our care and food has anything to do with gratitude. The simpler alternative is that, after prolonged deprivation, there is a constrast effect that lasts a lifetime, making these animals show greater-than-average expressions of pleasure at receiving a full bowl of food. In humans, no one would confuse pleasure with gratitude. On the other hand, if the pleasure is expressed in a personal manner, aimed specifically at the individual who delivers it, are not we getting closer to gratitude?
De Waal observed the common exchange of food for grooming among chimpanzees in order to determine if the trade of food for grooming is simply the result of proximity (as in the impala or vampire bat), or good feelings (as in the adopted domestic dog), or if it is somehow more computationally intensive, such as requiring the ability to direct reciprocity at specific individuals.
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Krisin E. Bonnie, & Frans B. M. de Waal. (2004) Primate Social Reciprocity and the Origin of Gratitude. in Robert A. Emmons , 213-229. info:/
DEWAAL, F. (1997) The Chimpanzee's service economy: Food for grooming. Evolution and Human Behavior, 18(6), 375-386. DOI: 10.1016/S1090-5138(97)00085-8
HART, B., & HART, L. (1992) Reciprocal allogrooming in impala, Aepyceros melampus. Animal Behaviour, 44(6), 1073-1083. DOI: 10.1016/S0003-3472(05)80319-7
Seyfarth RM, & Cheney DL. (1984) Grooming, alliances and reciprocal altruism in vervet monkeys. Nature, 308(5959), 541-3. PMID: 6709060
Bones of a giant manabou stork have been unearthed recently from the Pleistocene of Liang Bua cave in Flores, Indonesia. This new species, Leptoptilos robustus, is estimated to be 1.8 meters in length with an estimated weight of 16 kg. This stork has a reduced capacity for flight and would have been oriented more towards [...]... Read more »
HANNEKE J.M. MEIJER and ROKUS AWE DUE. (2010) A new species of giant marabou stork (Aves: Ciconiiformes) from the Pleistocene of Liang Bua, Flores (Indonesia). Zoological Journal of the Linnean Society. info:/
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