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Social networks and Cooperation

January 26, 2012 in Abstracts, Science News

A new paper in Nature, by Apicella, Marlowe, Fowler & Christakis, was published today. It hypothesises that social network structure may have been present in early human history, and this structure may account for the emergence of cooperation. The study used data from the Haza people of Tanzania, who presumably already have cooperation, so I’m not sure what data they’re using to back up claims of emergence. I can’t read the article because I don’t have institutional access any more, so I’d be keen to hear thoughts others have.

Here’s the abstract:

Social networks show striking structural regularities, and both theory and evidence suggest that networks may have facilitated the development of large-scale cooperation in humans. Here, we characterize the social networks of the Hadza, a population of hunter-gatherers in Tanzania. We show that Hadza networks have important properties also seen in modernized social networks, including a skewed degree distribution, degree assortativity, transitivity, reciprocity, geographic decay and homophily. We demonstrate that Hadza camps exhibit high between-group and low within-group variation in public goods game donations. Network ties are also more likely between people who give the same amount, and the similarity in cooperative behaviour extends up to two degrees of separation. Social distance appears to be as important as genetic relatedness and physical proximity in explaining assortativity in cooperation. Our results suggest that certain elements of social network structure may have been present at an early point in human history. Also, early humans may have formed ties with both kin and non-kin, based in part on their tendency to cooperate. Social networks may thus have contributed to the emergence of cooperation.

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Never mind language, emotions are in a category of their own

November 12, 2011 in Abstracts, Research Blogging, Science, Science News

A new paper in the journal ‘Emotion’ has presented research which has implications for the evolution of language, emotion and for theories of linguistic relativity. The paper, entitled ‘Categorical Perception of Emotional Facial Expressions Does Not Require Lexical Categories’, looks at whether our perception of other people’s emotions depend on the language we speak or if it is universal. The results come from the Max Planck Institute for Psycholinguistics and Evolutionary Anthropology.

Human’s facial expressions are perceived categorically and this has lead to hypotheses that this is caused by linguistic mechanisms.

The paper presents a study which compared German speakers to native speakers of Yucatec Maya, which is a language which has no labels which distinguish disgust from anger. This was backed up by a free naming task in which speakers of German, but not Yucatec Maya, made lexical distinctions between disgust and anger.

The study comprised of a match-to-sample task of facial expressions, and both speakers of German and Yucatec Maya perceived emotional facial expressions of disgust and anger, and other emotions, categorically. This effect was shown to be just as significant across the language groups, as well as across emotion continua (see figure 1.) regardless of lexical distinctions.

The results show that the perception of emotional signals is not the result of linguistic mechanisms  which create different lexical labels but instead shows evidence that emotions are subject to their own biologically evolved mechanisms. Sorry Whorfians!

References

Sauter DA, Leguen O, & Haun DB (2011). Categorical perception of emotional facial expressions does not require lexical categories. Emotion (Washington, D.C.) PMID: 22004379

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Support EVOLUTION: THIS VIEW OF LIFE

October 30, 2011 in Science, Science News

I just stumbled across this really cool project over at kickstarter. It’s for a website, Evolution: This View of Life, which is being run by the well-known evolutionary theorist, David Sloan Wilson. Here is the pitch from Sloan’s blog:

photo-full.jpgEVOLUTION:THIS VIEW OF LIFE is a new online general interest magazine in which all of the content is from an evolutionary perspective. It includes content aggregated from the internet and new content generated by a team of editors, all professional evolutionists, representing eleven subject areas. The editors work for free, in the same spirit as editors of academic journals. Their expertise enables EVOLUTION:THIS VIEW OF LIFE to feature evolutionary science in action, as stimulating for the professional as for the general public.

To help launch the magazine, we are trying to raise $5000 through Kickstarter, which will be used to support the central office and purchase equipment for video and audio recording. Contribute $50 or more and get a cool t-shirt with this logo designed by illustrator Kevin Cannon. Pledge $80 or more and we’ll record a videocast with you, so that you can share what evolution means to your view of life.

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Does a Smart Phone make Smart Science?

September 29, 2011 in Science, Science News

A new paper in plos one, published today, has shown that experiments on human cognition needn’t be confined to the lab.

Experiments on human cognitive abilities, such as language, often rely on testing small and homogeneous groups of volunteers (mostly undergraduate students) coming to research facilities where they are asked to participate in behavioral experiments. This arrangement is not ideal as your sample will not be representative of the population as a whole and will also be restricted as there is only so many participants that money and time will allow you to get into the lab to be tested.

This new research by Dufau et al. shows that the sampling limitations which laboratory experiments produce can be overcome by using smartphones. Using smart phone technology, data can be collected for cognitive science experiments from thousands of subjects from all over the world.

To illustrate how this can be done the authors carried out a large-scale study using  iPhone and iPads. This was a linguistic study looking at people’s ability to distinguish words from similar non-words.

The project, which began in December 2010 has managed to collect data from 4,157 subjects in just 4 months! This can be compared with the English Lexicon Project which acquired a similar volume of data using traditional methods which took more than 3 years.

The data was collected using applications which were produced in seven languages (English, Basque, Catalan, Dutch, French, Malay, Spanish). Smartphones can also support studies in alphabets other than Roman including Chinese, Greek, and Japanese. This creates the opportunity to create large-scale cross linguistic studies without even having to move from behind your desk.

Whilst the example here is linguistic there is every reason that smart phones can be implemented in looking at how universal other areas of cognitive behaviour are. Or even neurosceince and experimental philosophy.  I wonder if it would be possible to carry out experiments using transmission chains using smart phones.

However, I do worry that using things like iPhones will have the same problems as using things like mechanical turk, as it means that experimenters will not be able to make sure that participants are carrying out the tasks properly and removes quite a lot of control. Smartphones are also still a luxury and therefore only people within a certain socio-economic class will have smartphones, so maybe these methods may not reach such a wide audience, which seems to be why they’re being proposed in the first place.

The authors of the paper are hailing smartphones  ”a potential revolution in cognitive science” but only time will tell if this really kicks off!

Reference

Stephane Dufau, Jon Andoni Dun abeitia, Carmen Moret-Tatay, Aileen McGonigal, David Peeters, F.-Xavier Alario, David A. Balota, Marc Brysbaert, Manuel Carreiras, Ludovic Ferrand, Maria Ktori, Manuel Perea, Kathy Rastle, Olivier Sasburg, Melvin J. Yap, J (2011). Smart Phone, Smart Science: How the Use of Smartphones Can Revolutionize Research in Cognitive Science PlosOne, 6 (9) : 10.1371/journal.pone.0024974

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The Gestural Repertoire of the Wild Chimpanzee

May 8, 2011 in Science, Science News

In the past many studies have been done on the linguistic abilities of trained apes using artifical languages, but what about in the wild?

Catherine Hobaiter and Richard W. Byrne at the University of St. Andrews have carried out a new study looking at the intentional gestures of chimpanzees in the wild.

Whilst it is generall agreed that gestural communication in great apes as seen in the wild is intentional and elaborate and flexible the authors outline that there is still a lot of controversy with regards to interpretation of the system and how the apes acquire it. These questions are hard to untangle when studied in the captive settings of a zoo.

The study presents a systematic analysis of the gestures made by a population of chimpanzees in the wild. 4,397 cases of intentional gesture were recorded in Budongo, Uganda.

These recordings were used to identify 66 gesture types. These gestures were seen to differ between individuals and also between age classes. Regardless of these differences no gesture was used only by one individual. I worried when I first read this as sometime studies identify intentional gestures by using the criteria that the gestures were used in the same context a certain number of times, however, within this study the criteria for intention gesture was as follows:

Audience checking: The signaller shows signs of beingaware of the potential recipients and their state ofattention, e.g. turning to look at the recipient beforegesturing.

Response waiting: The signaler pauses at the end of thecommunication and maintains some visual contact.

Persistence: The production of further gestures, afterresponse waiting and in the absence of a response that in other cases is taken as satisfactory. (In certain circumstances, such persistence might be impossible, for example where an adult carries an infant away; these cases are marked as unable to persist, rather than nopersistence.)

The authors argue that these gestures are not acquired by ‘ontogenetic ritualization’, which is when actions which are performed to reach some goal become ritualised to the point that they can be anticipated from an intial gesture sequence. The authors carried out detailed analyses of two gestures to show that the action elements which the gestures were made up from did not match those of the original actions.

This lack of ontogenetic ritualisation may be down to these gestures being species-typical, or typical across all the great apes. Comparisons made with the recorded gestured of gorillas and orangutans show that chimpanzee overlap with at least 24 gestures which are recorded in all three species. Dr Hobaiter is cited as saying on the BBC story that:

“the gestures that apes use (and maybe some human gestures too) are derived from ancient shared ancestry of all the great ape species alive today.”

The gestures were also able to be used flexibly across contexts and were able to adjust to the audience, for example the chimps were shown giving silent gestures when their audience was attentive and used contact in their gestures when the audience was inattentive.

The paper includes extensive analysis of repertoire size across age groups, contexts each gesture type was used in as well as things like hand position and shape during gestures.

This is the first study of its type using a wild population of chimpanzees. It shows highly intentional use of a species-typical repertoire which seems surprising and certainly contributes evidence relating to the evolution of intentional communication.

Reference

Catherine Hobaiter and Richard W. Byrne (2011) The gestural repertoire of the wild chimpanzee. ANIMAL COGNITION. DOI: 10.1007/s10071-011-0409-2

 

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Cultural bottlenecks leads to Diversity in Birdsong

May 4, 2011 in Abstracts, Science News

A new study has been conducted on dialect formation in birds:

Native North Island saddlebacks have developed such distinctive new songs in the past 50 years that it is not clear if birds on one island recognise what their neighbours are singing about, a Massey University study shows.

The phenomenon is an avian equivalent of the way human language develops regional accents and dialects as people migrate and settle in new locations, and provides fresh insights into how species evolve, says biology researcher Dr Kevin Parker, from the Institute of Natural Sciences at Albany.

I can’t find any published article but the press release is here.

 

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Replicated Hauser Results

April 25, 2011 in Science News

Some of you may remember last summer Marc Hauser was found guilty of research misconduct. This investigation raised questions about several publications including a paper from 2007 in Science. This paper looked into the ability of non-human primates to understand the intentions of a human experimenter by interpreting his gestures.

Today Science has published a partial replication of the study in question which confirms the original findings that chimpanzees, cotton-top tamarins, and rhesus macaques can distinguish intentional gestures, such as pointing to indicate a container with food inside, from “accidental” actions such as a hand flopping against a container.

The Science wesite states the following:

Following the Harvard misconduct investigation, first author Justin Wood, now an assistant professor at the University of Southern California in Los Angeles, wrote to Science in June 2010 to notify the journal that the investigation had revealed that the original field notes for the rhesus experiments could not be found:

“An internal examination at Harvard University determined that there are no field notes, records of aborted trials, or subject identifying information associated with the rhesus monkey experiments; however, the research notes and videotapes for the tamarin and chimpanzee experiments were accounted for. Professor Hauser states that “most of the rhesus monkey observations were hand written by [co-author David D.] Glynn on a piece of paper, and then the daily results tallied and reported to Wood over email or by phone” and then the raw data were discarded. The research assistant who performed the experiments (Glynn) confirmed that these field notes were discarded.”

Hauser and Wood returned to Cayo Santiago island in Puerto Rico to redo the experiments from the 2007 paper with the same population of free-ranging rhesus monkeys. Their findings, including field notes and video trials, are available online and they essentially match those reported in the original paper.

It is still not known what went wrong with the original experiment, a statement issued by Science today only says the following:

We stress that this new publication aims only to determine whether the original rhesus monkey experiments from the 2007 paper can be replicated. It has no bearing on questions raised about Dr. Hauser’s larger body of work.

This article from Science Inside quotes Dario Maestriperi as saying:

“The results of this replication are straightforward and entirely consistent with those of the original study. If the authors’ interpretation of their results is correct, these findings are very important and represent one of the clearest demonstrations that nonhuman primates can interpret the behavior of other individuals as intentional or non-intentional….Since the experimenter who tested the rhesus monkeys in the replication study appeared from the video to be the first author on the paper, Justin Wood, he was clearly knowledgeable of the hypotheses being tested and had some strong expectations and desires about the monkeys’ performance on the test.”

So is this replication a clarification of groundbreaking findings or could the monkey’s behaviour be down to the Clever Hans effect?

Meanwhile investigations into Hauser’s research are still ongoing and he is still banned from teaching for the next academic year.

 

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Cultural Transmission observed in Whales

April 15, 2011 in Science, Science News

A new paper in Current Biology, published today has revealed that the songs of Humpbacked Whales are passed through the ocean by mechanisms of cultural transmission.

Cultural transmission is defined as the social learning of information or behaviours either over generations or via peers. It has been seen to occur in primates, cetaceans and birds.

Cultural transmission over generations, i.e. parent passing socially learnt traits to their offspring, is known as vertical transmission and cultural transmission via peers, unrelated individuals from within generations, is known as horizontal transmission. In humans, languages and memes are transmitted, learned and (in a lot of cases) evolved in this manner.

Male humpback whales have a repetitive and evolving ‘song’ which acts as a vocal sexual display. This song is highly repetitive and is used, by mechanisms of social sorting and attraction, to allow for sexual selection within the whale population. All males within a population are known to conform to the current version of the display (song type), and similarities have been seen to exist among the songs of populations within an ocean basin.

The study being discussed presents very strong evidence for patterns of horizontal transmission, whereby song types spread unidirectionally and rapidly in the pacific ocean eastward through populations in the western and central South Pacific. The study was done over an 11-year period. This is the first documentation of a repeated, dynamic cultural evolution occurring across multiple populations at such a large geographic scale and across such a large time scale.

The patterns of cultural transmission seen in these whales songs are analogous to the same mechanisms we see in humans given that the songs are subject to mistakes and changes which are replicated. This causes the same mechanisms we see in the cultural transmission of language. The authors note that the level and rate of change seen in the whales is unparalleled in any other nonhuman animal and involves culturally driven change at a vast scale.

They also state that:

Investigating the underlying mechanisms of song evolution may yield powerful insights into the transmission of cultural traits and the evolution of culture and plasticity in sexually selected traits.

They also observed that at least one of the song types was transmitted between two different ocean basins, the Indian and South Pacific Ocean. It’s amazing to think how far a single song type can be horizontally transmitted.

Humpback whale song is unique among the animal kingdom due to the conformity to the current norm. This is coupled with high plasticity in the trait (ability to change their song based on whatever the new ‘norm’ is). Why both plasticity and conformity might be selected, how these interact with sexual selection, and how cultural evolution influences both are intriguing questions in need of consideration.

References

Garland, E. C.; Goldizen, A. W.; Rekdahl, M. L.; Constantine, R.; Garrigue, C.; Hauser, N.; Poole, M. M.; Robbins, J.; Noad, M. J. (2011) Dynamic Horizontal Cultural Transmission of Humpback Whale Song at the Ocean Basin Scale. Current biology : CB doi:10.1016/j.cub.2011.03.019

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The path to empathy

April 7, 2011 in Evolution, Science, Science News

Published online at Plos one yesterday a study done at the Yerkes National Primate Research Center by Campbell and de Waal (2011) has found a link between social groups and empathy in chimpanzees as demonstrated by involuntary yawning responses.

The study is based on the psychological concept of ingroups and outgroups. In humans ingroups are those we see as similar to ourselves and outgroups are those we perceive as different.

Biases involved in ingroup-outgroup discrimination in know to even extend to involuntary responses which includes empathy for pain. This has never been tested in other animals though.

Contagious yawning is thought to be linked with empathy. The study used this assumption to test if chimpanzees’ ingroup-outgroup biases would effect how contagious a yawn can be. In other words if contagious yawning is linking to empathy and empathy is linked to ingroup-outgroup biases within chimpanzees then the chimpanzees should yawn more in response to watching ingroup members yawn than outgroup.

The study used 23 chimpanzees from two separate groups and they were made to watch videos of familiar and unfamiliar individuals yawning. Videos of the same chimps not yawning were also used for control. The chimpanzees yawned more when watching the familiar yawns than the familiar control or the unfamiliar yawns, demonstrating an ingroup-outgroup bias in contagious yawning.

The authors have suggested that these result may be more magnified in chimpanzees than it is in humans as chimpanzees live in much smaller communities than humans and are generally very hostile to those outside of their small social group. Ingroup-outgroup biases are therefore probably much more absolute in chimpanzees.

This study adds empirical evidence to suggest that contagious yawning is subject to empathy. This may have further implications for studying the evolutionary foundations of empathy which obviously has implications for things like theory of mind which is pretty high up on the list for preadaptations for language.

References

Campbell MW, de Waal FBM (2011) Ingroup-Outgroup Bias in Contagious Yawning by Chimpanzees Supports Link to Empathy. PLoS ONE 6(4): e18283. doi:10.1371/journal.pone.0018283

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The adaptive value of age, co-operation (and secret signals)

March 16, 2011 in Evolution, Science, Science News

More elephant based news!

A new study from the Proceedings of the Royal Society B, published today, has found that elephants pay attention to the oldest female elephant in their group when a predator is approaching.

The research, carried out in Kenya, used recordings of roars from both male and female lions and monitored the reactions of groups of African Elephants. It has been known for a long time that elephants social groups are formed around a matriarchy. The experiment found that groups of elephants with matriarchs quickly organised themselves into defensive bunch formations after appearing to stop and pay attention to their female leader. These groups were also much more likely to approach the loud speaker producing the roar in an aggressive manner.

Male lions present a greater threat to groups of elephants as they are much more likely to attack elephants when alone and are usually much more successful than females who will only attack when part of a group. The elephants showed an ability to differentiate between male and female lions. The study also showed that matriarchs who were much older were much more likely to react in the appropriate way to roars made by male lions which is thought to be the result of experience.

The signals which allow the Matriarch to elicit this co-ordination among her group are still largely unknown due to the lack of loud vocalisations and Karen McComb and Graeme Shannon, who lead the initial study, are now looking into finding quieter, less obvious vocalisations and posture cues.

The study provides the first empirical evidence that within a social group, individuals may gain benefits from paying attention to an older leader because of their abilities in making decisions when under threat. This generates insights into selection for longevity in cognitively advanced social mammals.

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