Category: Science News

Cultural bottlenecks leads to Diversity in Birdsong

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.

 

Replicated Hauser Results

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.

 

Cultural Transmission observed in Whales

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

The path to empathy

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

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

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.

Out of (Southern??) Africa

It is a largely unchallenged claim of anthropologists that the human race emerged from the continent of Africa. However, claims relating to our evolution before our nomadic ancestors left the land of our origin have been left largely abstruse.

A new paper published on PNAS.org this week attempts to address this very problem through genetic analysis of several hunter gatherer societies in Africa including speakers of the nearly distinct N|u language. This was done because hunter-gather populations remain divergent in their variations at a level which is no longer maintained in the African population as a whole.

580,000 Single-nucleotide polymorphisms (SNPs) were analysed to calculate genetic relationships and diversity between the groups and propose possible evolutionary paths and branches.

Henn et al. (2011) propose that the genetics of those groups found in the south of Africa are the most diverse, and therefore the oldest, of any diversity found among other modern humans. This has caused them to suggest that the origins of modern humans may in fact be in southern Africa as opposed to the much more accepted view which is that we emerged from the east of Africa.

This assumed eastern viewpoint is a result of the earliest modern human skulls being found in the east and also the fact that humans in the rest of the world all carry a subset of genes found specifically in eastern Africa. However, until now, the populations represented in the study by Henn et al. (2011) have not been represented in previous genetic studies when making estimates of the whereabouts of our evolutionary origins.

Some dispute has arisen regarding these conclusions because the current whereabouts of these hunter-gatherer populations within Africa is not evidence to suggest that this is always where these populations have resided. These groups may have moved about and migrated from their original place of origin just as the rest of humanity has. Henn has retorted that, though this is a possibility, typically only a subset of a group moves to a new area, and this subset is less genetically diverse than the parent population. This would mean that if a group of humans left eastern African for southern Africa they would be expected to be less diverse in the population who moved and this contradicts the genetic data found in Henn et al. (2011).

References

Henn, B. et al. (2011) Proc. Natl Acad. Sci. USA doi:10.1073/pnas.1017511108

Elephants give each other a helping trunk

A study published on PNAS.org yesterday has shown that elephants might have shared goals which gives them the ability to co-operate.

An experiment was done using the classical 1930s cooperation paradigm used to test the co-operative abilities of monkeys and apes. This paradigm is used to explore the cognition underlying coordination toward a shared goal. This explores what animals know or learn about the benefits of cooperation and also tests their ability to comprehend a partner’s role in cooperation.

The experiment comprises of 2 animals who need to work together to pull 2 ends of the same rope in order to pull a platform towards them which holds a reward such as food.

Experiments such as this have never been done on animals apart from primates before. Plotnik et al. (2011) subjected this experimental paradigm to elephants and have shown that elephants can learn to coordinate with a partner. The elephants also delayed pulling he rope for up to 45 seconds if the arrival of their partner was delayed which showed that they comprehended that there was no point to pulling on the rope if their partner lacked access to the rope. The elephants learnt that this was the case much more quickly than has been shown in Chimpanzees in other studies.

Observations from the wild suggest that in nonhuman primates these co-operative abilities exist but experimental results have been mixed. Plotnik et al. (2011) claim that convergent evolution may have lead elephants to have reached a level of cooperative skill equal to that of chimpanzees.

You can see a video of the elephants doing the experiment here: http://news.bbc.co.uk/earth/hi/earth_news/newsid_9417000/9417308.stm

References

Plotnik, J. M., R. Lair, w. Suphachoksahakun & F. B. M. de Waal (2011)
Elephants know when they need a helping trunk in a cooperative task. PNAS 2011 : 1101765108v1-201101765.

The Quill to Communicate?

New footage has been filmed of a little known animal called the Streaked Tenrec in Madagascar. The footage shows the creatures can rub their quills together to make ultrasound calls and can also produce tongue clicks  to each other which are outside of the range of human hearing.  Because of the ultra sonic nature of these sounds, it has been unknown quite to the extent that these creatures can do this, before now.

The BBC, who’s film crew for the new ‘Madagascar’ series filmed the animals, states in their article about the new findings:

Using the bat detector, the filmmakers found that the seemingly “quiet” mammals were constantly communicating.

and

Few studies have been made to investigate why streaked tenrecs communicate both vocally and via their quills but they are currently the only mammals known to do so.

This may be a classic misuse of the word ‘communicate’ in that just because an animal is making a noise does not make that noise communicative. At no point in the article does it make any claim about what it might be that they are trying to communicate to each other and the only assertation that is made as to why the Tenrecs might be making ultrasonic noises is when the story goes on to state that scientists hypothesize that these ultrasonic sounds are being used as echo location and so to call these sounds communication is the same as calling our ability to see where we’re going communicative (it’s not).

Not to completely discredit the premise of the story by the BBC, the behaviour of producing the ultrasonic sounds using the quills could be a form of stridulation which is used by other animals to attract a mate, act as a warning signal or to protect territory. If this is the case it could be groundbreaking stuff as stridulation has never been seen before in mammals. But until the production of sound can be seen to manipulate the behaviour of others it seems ‘communication’ may be too strong of a word.

Bipedalism: New Fossil Evidence and Language Evolution

Published in Science today, 11.02.2011 (yey! palidromic date!) is a report on the find of a Complete Fourth Metatarsal and Arches in the Foot of Australopithecus afarensis.

New fossil evidence from Hadar, Ethiopia suggests that our ancestors from 3.2 million years ago (Australopithecus afarensis (better known as Lucy)) had arches in their feet.

Arched feet are an essential part of the bipedal way that modern humans walk.

Although the skeleton of Lucy was found in 1974, until now important foot bones in all of the specimens uncovered to date have made it difficult for researchers to understand precisely how well adapted for bipedalism a. afarensis were.

Why should people interested in Language Evolution care about bipedalism? Well, here’s some food for thought:

1) Bipedalism likely had an impact on our cognitive abilities. As climbing as a form of locomotion became less common, different ways to cognitively represent space and distance probably had to be found. These new systems could have involved imitation (mirror neuron alarm bells start ringing). By adding imitative abilities to already existing spacial awareness that are seen in modern, non-human primates, this may have created mechanisms which allowed hominins to visualise themselves walking across plains (McWhinney 2005). This may have been the original selective pressure for imitative ability and therefore could have some implications for the imitative abilities which exist within language.

2) Upright posture would free up forelimbs which may have had communicative advantages as it would free the hands up for gesture. This theory has been somewhat rubished in that  the first apes to adapt a bipedal posture were probably cognitively not much different from today’s apes (assumed from evidence of skull size). However even if this was not the selective pressure FOR bipedalism it doesn’t stop it being relevant to the discussion.

3) Free hand movement would also lead to making tools. Stone tools getting more complex and language developing as evolution took place may show a close relationship between enhanced motor movement and language. Deficits in motor control are also often linked to aphasia so there is a strong connection between manual activity and speech communication.

4) When Chimpanzees and Gorillas are socializing in groups they go from a ‘knuckle walk’ to sitting in circles, this allows apes to keep eye contact with each other in social situations,  bipedalism would also allow one to keep eye contact at all times, even when in motion, and so the this may have been a selective pressure. Stanford (2003)

5) Evolution of the cortico-striatal neural circuits (basal ganglia) that regulate human language may have been shaped by the demands of upright bipedal locomotion. (Lieberman, 2001)

A lot of this debate is quite controversial but I thought I’d put some thoughts/theories out there in celebration of exciting new finds!

References

Lieberman, P. (2001) On the subcortical bases of the evolution of language. In Jurgan Trabant and Sean Ward, editors, New Essays on the Origins of Language, pages 21–40. Berlin-New York:Mouton de Gruyter.

McWhinney, B. (2005) Language Evolution and Human Development. In Bjorklund, D. and Pellegrini, A. (Eds.). Origins of the Social Mind: Evolutionary Psychology and Child Development (pp 383-410). New York: Guilford Press.

Stanford, C. B. (2003). Upright: The evolutionary key to becoming human. New York: Houghton Mifflin

Ward, C. V., W. H. Kimbel & D. C. Johanson (2011) Complete Fourth Metatarsal and Arches in the Foot of Australopithecus afarensis. Science: 331 (6018), 750-753.

Project Nim

How cool is this? They’ve made a movie about Nim Chimpsky called Project Nim!

By the same guys who made Man on Wire, it’s currently been shown at the Sundance Festival.

Nim was  raised and nurtured like a human child in order to see to what extent apes could acquire human language.

SO CUTE!

Following Nim’s extraordinary journey through human society, and the enduring impact he makes on the people he meets along the way, the film is an unflinching and unsentimental biography of an animal we tried to make human. What we learn about his true nature – and indeed our own – is comic, revealing and profoundly unsettling.

 

http://sundance.slated.com/2011/films/projectnim_sundance2011