Observational learning in octopus vulgaris

A few months ago, a documentary I saw on the Discovery Channel covered some research by Graziano Fiorito and colleagues at the Stazione Zoologica  in Naples. They were investigating observational learning in wild Octopus vulgaris with a puzzle-box experiment similar to those demonstrating cultural transmission in chimpanzees.

It goes like this: there’s a tasty and terrified crustacean running around in a perspex box that has two possible ways of being opened by hungry octopuses. The experimenters capture a wild octopus (let’s call him Steve) from the harbour (which I’ll get back to in a minute), and they put it in a tank with the puzzle-box. After Steve stares hopelessly at the box for a while, it is then removed from the tank. Steve the kidnapped octopus then gets to watch a captive octopus in the next tank being presented with the same puzzle-box containing the delicious crab. Of course, the captive octopus has been confronted with the puzzle-box enough times that it has worked out a successful solution, and so opens the box like a pro. Steve is then presented with a crab in a puzzle-box again, except this time he goes straight for the crab using the same solution he just learned from the captive octopus. Here is a clip from the documentary, showing a trial of this experiment (NB: not the best quality).

It turns out that the papers on this go back as far as Fiorito & Scotto 1992, and it seems this was the first time observational learning had been demonstrated in invertebrates. The reason I’m interested in reporting this is because the documentary I watched explained another possible motivation/interpretation for Fiorito’s work that I can’t find in any of his actual papers. The octopuses used in the experiments were all caught from the harbour at Naples just before the experiments, which of course controlled for any prior experience with the puzzle boxes. But the results were reported as particularly interesting because the Naples harbour had been overfished and disrupted, resulting in an increase in marine predators that eat the small octopus vulgaris as well as fish that the octopuses themselves rely on. These harsher environmental conditions resulted in the octopuses being forced to inhabit a smaller space alongside each other. As a result, young octopuses were frequently exposed to, and even coexisted with, older octopuses. This is a weird situation for an octopus; they usually live solitary lives and never even meet their own mothers, who die of starvation while caring for the eggs (the fathers die within a few months of having mated). The only real interactions are mating, and conflicts between rival males while competing for a mate.

Toward the end of the documentary, the voiceover growled against some dramatic music about how the combination of observational learning capacities and increased predation pushing octopuses into groups meant that it was only a matter of time  before we’re overthrown by octopus vulgaris. This made me think of Dunbar’s “social brain hypothesis” for the emergence of language, and whether I really should prepare to welcome our new octopus overlords. Talking specifically about primates, Dunbar (1996) states that “[primates] in general exhibit two responses to increased predation: they grow physically bigger [or] they increase the size of their groups” (p.110). In order to maintain these groups, that are essential for survival in harsh ecological conditions, Dunbar suggests that standard primate grooming behaviour becomes too time consuming and costly in order to keep up with the rapidly expanding social group, creating a pressure for a more efficient method of bonding and communicating that allows the size of the group to continue increasing. Again with reference just to primate communication, Dunbar says “This [efficient mechanism] need not have involved any dramatic change, for as the studies by Seyfarth and Cheney have shown, primate vocalizations are already capable of conveying a great deal of social information and commentary.” (p.115) In addition to primates, and adding further credence to this idea, it’s been shown that the older Matriarchs of elephant groups make use of vocalisations to seemingly instruct their group on how to fend off lion attacks (McComb et al., 2011; previous Replicated Typo coverage here). It seems to me that the difference between the primates/elephants and the octopuses is that the former endeavour to actually enrich the environment from which their conspecifics extract information; they don’t just learn, they inform. As far as we can tell, there is no such communication like this – that is, enriching the environment in some way that helps other octopuses learn or survive – happening among the octopuses. That said, we know from mating displays and conflicts that cephalopods can communicate with chromatophore signalling. As an interesting aside that is reflective of their cognitive abilities and capacity for suffering, octopuses are treated as honorary vertebrates by UK animal testing laws.

It’s interesting enough that marine biologists (or at least those reporting on marine biologists) seem to have the same idea as Dunbar about the necessary preconditions for successful societies of animals, but why not let’s get wildly speculative? If (..!) existing in groups is in fact adaptive for these octopuses in the face of increased predation, and the competition between them for resources isn’t too great a counter-factor, it seems the only ingredient missing from an octopocalypse is the emergence of some cooperative behaviour. Someone should keep an eye on that harbour.

 

References

Dunbar, R. (1996) Grooming, Gossip, and the Evolution of Language. Harvard University Press: Cambridge, Massachusetts

Fiorito, G. & Scotto, P. (1992) “Observational learning in Octopus vulgaris” Science 256, 545-546.

McComb, K., Shannon, G., Durant, S., Sayialel, K., Slotow, R., Poole, J. & Moss, C. (2011) “Leadership in elephants: the adaptive value of age” Proceedings of the Royal Society B, published online.

James Hurford: Animals Do Not Have Syntax (Compositional Syntax, That Is)

After passing my final exams I feel that I can relax a bit and have the time to read a book again. So instead of reading a book that I need to read purely for ‘academic reasons’, I thought I’d pick one I’d thoroughly enjoy: James Hurford’s “The Origins of Grammar“, which clocks in at a whopping 808 pages.
I’m still reading the first chapter (which you can read for free here) but I thought I’d share some of his analyses of “Animal Syntax.”
Hurford’s general conclusion is that despite what you sometimes read in the popular press,

“No non-human has any semantically compositional syntax, where the form of the syntactic combination determines how the meanings of the parts combine to make the meaning of the whole.”

The crucial notion here is that of compositionality. Hurford argues that we can find animal calls and songs that are combinatorial, that is songs and calls in which elements are put together according to some kind of rule or pattern. But what we do not find, he argues, are the kinds of putting things together where the elements put together each have a specified meaning and the whole song, call or communicative assembly “means something which is a reflection of the meanings of the parts.”

(Link)
To illustrate this, Hurford cites the call system of putty-nosed monkeys (Arnold and Zuberbühler 2006). These monkeys have only two different call signals in their repertoire, a ‘pyow’-sound that ‘means’, roughly, ‘LEOPARD’; and a ‘hack’ sound that ‘means’, roughly, ‘EAGLE’.

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Stephen Fry’s Planet Word

Stephen Fry has embarked on a series of documentaries about language, beginning with the evolution of language which he calls ‘the final frontier’ of human understanding.  The typical documentary hype is all here:  Stephen Pinker sits in a gigantic fish tank with bits of taxidermied brain lying around like sandwiches; Michael Tomasello appears to live in a tropical primate enclose; Fry conducts his studies from a medieval study complete with quills, a CGI tree of languages and a talking parrot.

Despite this, it was actually a coherent and comprehensive review of topics in the field: Language versus communication in animals, phisological constraints of language, creativity and the desire to share information, the pragmatic origins of language, FoxP2 and the poverty of the stimulus. Bilingualism is even added to this cannon of interesting ways to approach the origins of language, somewhat tempered by Fry’s question “wouldn’t it be better if everybody spoke Esperanto?”.

Mercifully, Fry seems to be actually interested rather than trying to build up the conspiracy plot format endemic in other science documentaries.  There are some odd diversions to a Klingon version of Hamlet, a trip to a German Christmas market and a slightly awkward re-enactment of a feral child case, but all in all the message is not objectionable: There is a graded difference between non-human and human communication, it’s partly genetic and partly cultural and languages continually change under pressures to be learned and to express new ideas.  There are also welcome additions of the original Wug test and, of course, Fry & Laurie’s seminal sketch about language.

Overall, I’d say it was the second best documentary the BBC have made about the origins of language.

Here’s a clip:

 

Also a clip of Fry talking about the series:

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.

Imitation and Social Cognition (III): Man’s best friend

In my two previous posts (here and here) about imitation and social cognition I wrote about experiments which showed that
1)  young children tend to imitate both the necessary as well as the unnecessary actions when shown how to get at a reward, whereas wild chimpanzees only imitate the necessary actions.
And that
2) both 14-month old human infants as well as enculturated, human raised-chimpanzees tend to ‘imitate rationally.’ That is, they tend to be able to differentiate whether an agent chose a specific way of performing an action intentionally, or whether the agent was forced to performing the action in this specific manner by some constraint.
ResearchBlogging.orgIt can be argued that these experiments demonstrate that human infants and young children show an early sensitivity to the communicative intentions of others. That is, they seem to be able to infer that a demonstrator’s specific (and ‘odd’ ) actions are somehow relevant, because she chose this specific manner freely (see also these two extremely interesting posts by the philosopher Pierre Jacob, on which my own post is partly based)

The fact that human-raised chimpanzees also show this sensitivity suggests that enculturation plays an important part in this process.
In a very interesting study, Range et al. (2007) used an experimental setup similar to that of Gergely et al. (2002) (which i described in my second post, here) to test whether other ‘enculturated’ and domesticated animals show the same kind of sensitivity: dogs.

Intelligence: Darwin vs. Wallace

It’s Charles Darwin’s birthday today! He’s 202. So in celebration I’ve written a post on the still ongoing controversy which the theory of evolution by natural selection caused and is causing, specifically with regards to the emergence of human intelligence.

Alfred Russel Wallace is widely seen as the co-discoverer of the theory of evolution by natural selection. While Darwin had been formulating his theory from as early as the late 1830s, he kept quite about it for more than twenty years while he amassed evidence to support it. In 1858 Alfred Russell Wallace, a naturalist of the same time, sent Darwin a letter outlining for him a theory of evolution which very closely mirrored Darwin’s own. The pair co-presented their theory to the Linnaean Society in 1858 but due to Darwin’s long time amassing evidence and refining his ideas, it was his book, On The Origin of Species, which was published in 1859 and set Darwin’s name firmly in the history books as the discoverer of natural selection.

While Wallace’s part in the discovery of natural selection is far from undocumented or unknown, it is largely for presenting ‘the same ideas’ as Darwin for which he is known and what is rarely discussed in the differences in their ideas. In this post I will briefly discuss a new(ish) paper by Steven Pinker on the evolution of human intelligence and some the differences between the thinking of Darwin and Wallace on the subject.

Darwin, unsurprisingly, asserted that the abstract nature of human intelligence can be fully explained by natural selection. In opposition to this Wallace claimed that it was of no use to ancestral humans and therefore could only be explained by intelligent design:

“Natural selection could only have endowed savage man with a brain a few degrees superior to that of an ape, whereas he actually possesses one very little inferior to that of a philosopher.”(Wallace, 1870:343)

Unsurprisingly most scientists these days do not agree with Wallace on either the point that the human brain could not be the result of natural selection or that as a result of this problem it must have been a product of design by a higher being. It would be both dismissive and dull to leave the discussion at that however, which is where Pinker comes in. Despite Wallace’s argument probably coming to the wrong conclusion he does bring up some very interesting questions which need answering, namely that of; “why do humans have the ability to pursue abstract intellectual feats such as science, mathematics, philosophy, and law, given that opportunities to exercise these talents did not exist in the foraging lifestyle in which humans evolved and would not have parlayed themselves into advantages in survival and reproduction even if they did?” (Pinker, 2010:8993)

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Sexual Selection in the age of Mass Media

This month a red deer was crowned as Emperor of Exmoor and Britain’s largest wild animal in a series of newspaper articles.  Today, it’s emerged that the deer has been shot by a hunter willing to pay the presumably high price on the hunting rights.

When Richard Austin, the photographer that took the pictures for the articles, was asked if he felt responsible, he said that he always believed the size of the deer’s antlers would get him killed in the end.  The Emperor’s antlers may have kept other deer away, but it attracted far deadlier predators.  Humans have been breeding animals – and killing them – for sport for a long time, but it’s only recently that prize targets can be advertised so widely.  The size of the antlers may be a product of sexual selection, but now cultural processes are counteracting this.  The Emperor was even killed during the mating season, unable to pass on its genes.  If you’re a deer, it’s maybe best to stay mid-size rather than risk the growing threat of trophy-hunting.

A history of evolution pt. 2: The Wealth of Nations, Populations and On the Origin

Title page of the original edition of Malthus' 1798 work

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The Problem With a Purely Adaptationist Theory of Language Evolution

According to the evolutionary psychologist Geoffrey Miller and his colleagues (e.g Miller 2000b), uniquely human cognitive behaviours such as musical and artistic ability and creativity, should be considered both deviant and special. This is because traditionally, evolutionary biologists have struggled to fathom exactly how such seemingly superfluous cerebral assets would have aided our survival. By the same token, they have observed that our linguistic powers are more advanced than seems necessary to merely get things done, our command of an expansive vocabulary and elaborate syntax allows us to express an almost limitless range of concepts and ideas above and beyond the immediate physical world. The question is: why bother to evolve something so complicated, if it wasn’t really all that useful?

Miller’s solution is that our most intriguing abilities, including language, have been shaped predominantly by sexual selection rather than natural selection, in the same way that large cumbersome ornaments, bright plumages and complex song have evolved in other animals. As one might expect then, Miller’s theory of language evolution has been hailed as a key alternative to the dominant view that language evolved because it conferred a distinct survival advantage to its users through improved communication (e.g. Pinker 2003). He believes that language evolved in response to strong sexual selection pressure for interesting and entertaining conversation because linguistic ability functioned as an honest indicator of general intelligence and underlying genetic quality; those who could demonstrate verbal competence enjoyed a high level of reproductive success and the subsequent perpetuation of their genes. Continue reading “The Problem With a Purely Adaptationist Theory of Language Evolution”

Theory of Mind and Language Evolution; What can psychopathology tell us?

Theory of Mind is the ability to infer other persons’ mental states and emotions. It is thought to have evolved as part of the human’s social brain and probably emerged as an adaptive response to increasingly complex primate social interaction.

Brüne and Brüne-Cohrs (2006) explore the ‘evolutionary cost’ of language evolution:

This sophisticated ‘metacognitive’ ability comes at an evolutionary cost, reflected in a broad spectrum of psychopathological conditions. Extensive research into autistic spectrum disorders has revealed that theory of mind may be selectively impaired, leaving other cognitive faculties intact. Recent studies have shown that observed deficits in theory of mind task performance are part of a broad range of symptoms in schizophrenia, bipolar affective disorder, some forms of dementia, ‘psychopathy’ and in other psychiatric disorders.

Now it’s fairly uncontroversial to assert that without the ability of theory of mind humans would have never evolved language (Sperber and Wilson, 2002). This is due to the fact that if one can’t attribute another to have a ‘mind’ like ones own, or assume that other minds hold different information to ones own then one would see little point in trying to share information. (I’m sorry for the amount of ‘ones’ in that sentence).

Sooo, it does not seem presumptuous to assume that people interested in the evolution of language should be interested in theory of mind, in fact for many years evolutionary linguists, psychologists and biologists have been looking into this, but mostly through observing the behaviour of animals, and especially primates to see if they display theory of mind capabilities. A good summary of this work can be found here, and a lot of relevant studies can be found on this blog in the What makes humans unique? posts by Michael. I’m not going to look at the animal data in this post, but instead what the deficiencies in some human conditions can tell us about the evolution of theory of mind. That is, what can autism, schizophrenia, bipolar affective disorder, dementia, ‘psychopathy’ and other psychiatric disorders tell us?

Continue reading “Theory of Mind and Language Evolution; What can psychopathology tell us?”