Culture, its evolution and anything inbetween
Continuing my series on the Evolution of Colour terms, this post reviews evidence for environmental constraints on colour perception. For the full dissertation and for references, go here.
Continue reading “Evolution of Colour Terms: 2 Environmental Constraints”
In a series of posts, I’ll review the current state of the field of the Evolution of Colour Categories. It has been argued that universals in colour naming across cultures can be traced back to constraints from many domains including genetic, perceptual and environmental. I’ll review these arguments and show that if our perception is affected by our language, then many conflicts can be resolved. Furthermore, it undermines the Universalist assumption that universal patterns in colour terms are evidence for innate constraints.
Part 1: Domains of Constraint
Part 2: Universal patterns are not evidence for innate constraints
Universal Patterns are not Evidence for Innate Constraints
For the full dissertation and for references, go here.
How is it, then, that we can talk about talking? If you are willing to assume the existence of basic perceptual and cognitive capacities, a relatively simple answer follows immediately. The sounds of talk are, after all, sounds like any other sounds. We can perceive them in the same way we perceive the sound of a waterfall or a bird’s song, a thunderclap or the rustling of leaves in the wind, a cricket’s chirp or the breaking of waves on a beach. All are things we can hear, easily and naturally, and so it is with the sound of the human voice.
Roman Jakobson famously theorized that language has six functions: referential, emotive, poetic, conative, phatic, and the metalingual function. That’s the function we’re interested in, our capacity to speak about speech. Jakobson talked of the metalingual function as an orientation toward the language code, which seems just a bit grand. For I’m led to believe that many languages lack terms for explicitly talking about the ‘code.’ Thus, in The Singer of Tales (Atheneum 1973, orig. Harvard 1960), Albert Lord attests (p. 25):
Man without writing thinks in terms of sound groups and not in words, and the two do not necessarily coincide. When asked what a word is, he will reply that he does not know, or he will give a sound group which may vary in length from what we call a word to an entire line of poetry, or even an entire song. [Remember, Lord is writing about oral narrative.] The word for “word” means an “utterance.” When the singer is pressed then to way what a line is, he, whose chief claim to fame is that he traffics in lines of poetry, will be entirely baffled by the question; or he will say that since he has been dictating and has seen his utterances being written down, he has discovered what a line is, although he did not know it as such before, because he had never gone to school.
While I’m willing to entertain doubts about the full generality of this statement – “man without writing” – I assume the it is an accurate report about the Yugoslavian peasants among whom Milman Parry and Albert Lord conducted their fieldwork and that it also applies to other preliterate peoples, though not necessarily to all.
Given those caveats, the paragraph is worth re-reading. Before doing so, recall how casually we have come to see language as a window on the workings of the mind in the Chomskyian and post-Chomskyian eras. If that is the case, then what can one see through a window that lacks even a word for words, that fails to distinguish between words and utterances? And what of the poets who don’t know what a line is? The lack of such knowledge does not stand in the way of the poeticizing, no more than the lack of knowledge of generative grammar precludes the ability to talk intelligently on a vast range of subjects.
What Makes Humans Unique (IV): Shared Intentionality – The Foundation of Human Uniqueness?
Shared or collective intentionality is the ability and motivation to engage with others in collaborative, co-operative activities with joint goals and intentions. (Tomasello et al. 2005). The term also implies that the collaborators’ psychological processes are jointly directed at something and take place within a joint attentional frame (Hurford 2007: 320, Tomasello et al. 2005).
Michael Tomasello and his colleagues at the Max-Planck-Institute for Evolutionary Anthropology in Leipzig, Germany have proposed that shared intentionality and the cognitive infrastructure supporting it may be the crucial feature that makes humans unique.
(You can hear Michael Tomasello talk about shared intentionality in his brief 2009 acceptance speech for the prestigeous “Hegel-Price” here. Transcript here)
In my last post I summed up some proposals for what (among other things) makes human cognition unique. But one thing that we should bear in mind, I think, is that our cognitive style may more be something of an idiosyncrasy due to a highly specific cognitive specialization instead of a definitive quantitative and qualitative advance over other styles of animal cognition. In this post I will look at studies which further point in that direction.
Chimpanzees, for example, beat humans at certain memory tasks (Inoue & Matsuzawa 2007) and behave more rational in reward situations (Jensen et al. 2007).
In addition, it has been shown that in tasks in the social domain, which are generally assumed to be cognitively complex, domesticated animals such as dogs and goats (Kaminski et al. 2005) fare similarly well or even outperform chimpanzees.
Social Cognition and Self-Domestication
It is entirely possible that the first signs of human uniqueness where at first simply side-effects our self-domesticating lifestyle – the same way the evolution of social intelligence in dogs and goats is hypothesised to have come about –, acting on a complex primate brain (Hare & Tomasello 2005).
This line of reasoning is also supported by domesticated silver foxes which have been bred for tameness over a time period of 50 years but developed other interesting characteristics as a by-product: To quote from an excellent post on the topic over at a Blog Around the Clock (see also here):
“They started having splotched and piebald coloration of their coats, floppy ears, white tips of their tails and paws. Their body proportions changed. They started barking. They improved on their performance in cognitive experiments. They started breeding earlier in spring, and many of them started breeding twice a year.”
What seems most interesting to me, however, is another by-product of their experimental domestication: they also improved in the domain of social cognition. For example, like dogs, they are able to understand human communicative gestures like pointing. This is all the more striking because, as mentioned above, chimpanzees do not understand human communicative gestures like helpful pointing. Neither do wolves or non-domesticated silver foxes (Hare et al. 2005).
What makes humans unique? This never-ending debate has sparked a long list of proposals and counter-arguments and, to quote from a recent article on this topic,
“a similar fate most likely awaits some of the claims presented here. However such demarcations simply have to be drawn once and again. They focus our attention, make us wonder, and direct and stimulate research, exactly because they provoke and challenge other researchers to take up the glove and prove us wrong.” (Høgh-Olesen 2010: 60)
In this post, I’ll focus on six candidates that might play a part in constituting what makes human cognition unique, though there are countless others (see, for example, here).
One of the key candidates for what makes human cognition unique is of course language and symbolic thought. We are “the articulate mammal” (Aitchison 1998) and an “animal symbolicum” (Cassirer 2006: 31). And if one defining feature truly fits our nature, it is that we are the “symbolic species” (Deacon 1998). But as evolutionary anthropologists Michael Tomasello and his colleagues argue,
“saying that only humans have language is like saying that only humans build skyscrapers, when the fact is that only humans (among primates) build freestanding shelters at all” (Tomasello et al. 2005: 690).
Language and Social Cognition
According to Tomasello and many other researchers, language and symbolic behaviour, although they certainly are crucial features of human cognition, are derived from human beings’ unique capacities in the social domain. As Willard van Orman Quine pointed out, language is essential a “social art” (Quine 1960: ix). Specifically, it builds on the foundations of infants’ capacities for joint attention, intention-reading, and cultural learning (Tomasello 2003: 58). Linguistic communication, on this view, is essentially a form of joint action rooted in common ground between speaker and hearer (Clark 1996: 3 & 12), in which they make “mutually manifest” relevant changes in their cognitive environment (Sperber & Wilson 1995). This is the precondition for the establishment and (co-)construction of symbolic spaces of meaning and shared perspectives (Graumann 2002, Verhagen 2007: 53f.). These abilities, then, had to evolve prior to language, however great language’s effect on cognition may be in general (Carruthers 2002), and if we look for the origins and defining features of human uniqueness we should probably look in the social domain first.
Corroborating evidence for this view comes from comparisons of brain size among primates. Firstly, there are significant positive correlations between group size and primate neocortex size (Dunbar & Shultz 2007). Secondly, there is also a positive correlation between technological innovation and tool use – which are both facilitated by social learning – on the one hand and brain size on the other (Reader and Laland 2002). Our brain, it seems, is essential a “social brain” that evolved to cope with the affordances of a primate social world that frequently got more complex (Dunbar & Shultz 2007, Lewin 2005: 220f.).
Thus, “although innovation, tool use, and technological invention may have played a crucial role in the evolution of ape and human brains, these skills were probably built upon mental computations that had their origins and foundations in social interactions” (Cheney & Seyfarth 2007: 283).
I’m reading a book at the minute called ‘The descent of madness: Evolutionary Origins of Psychosis and the Social Brain’ by Jonathan Burns. I thought I’d summarise some of the theories in the book as to how schizophrenia came about, for the principle reason that it’s very bloody interesting.
Some evolutionary thinkers have posited that schizophrenia is a recent disorder which is a modern response to the stresses of the industrial and technological age. Burns argues against this and claims that there is evidence of schizophrenia from early human history.
So, how and why did schizophrenia evolve when it has such a maladaptive nature? It’s certainly not being selected out because the phenotype still persists with a similar rate of incidence across the human race.
The Adaptionist Programme has a solution for this problem of mental disorders in that it views them as behavioural traits which evolved due to an advantage for the the individual in the ‘ancestral environment’, however, now, in a world which has changed and become psychologically stressful, a mismatch is created between the evolved trait and the modern environment.
The persistence of the phenotype can also be explained by taking into account the fact that psychotic illness has a continuum on which schizophrenia is a severe end of the spectrum, because of this other phenotypes on the genetic spectrum could harbour particularly adaptive traits. Genetically related but unaffected individuals who share some of the milder features of the illness may possess some kind of evolutionary advantage and hence the phenotype would linger.
The hypotheses above are plausible by Jonathan Burns claims he has a better solution:
Our hominid ancestors evolved a sophisticated neural network supporting social cognition and adaptive interpersonal behaviour (in other words the social brain). This has been identified, using functional imaging, to be comprised in the fronto-temporal and fronto-parietal cortical networks. Psychosis (and schizophrenia in particular) are characterised by functional and structural deficits in these areas and hence the term ‘social brain disorders’ are fitting.
Schizophrenics display abnormalities in a wide range of social cognition tasks such as emotion recognition, theory of mind and affective responsiveness and as a result individuals with schizophrenia find themselves disadvantaged in the social arena and vulnerable to the stresses of their complex social environments.
So, since there is such evidence to support that the areas which comprise our ‘social brains’ are the same regions which contribute to the disorder of schizophrenia when functional and structural deficits are present it becomes clear that schizophrenia exists as a consequence to the complex social brain.
This is a desirable hypothesis due to the fact that it does not rely on a Cartesian model of an isolated ethereal mind separated from body and environment, and instead concentrates on a physically and socially integrated construct of mind, embodied in the living world.
Interesting.
I’d just like to add a small disclaimer which says that I’m not an expert in schizophrenia or pretty much anything I’m writing about here (I haven’t even finished the book) so sorry if I’ve got anything hideously wrong. Please tell me. I’ll revisit this with extra thoughts on the subject once I have finished the book.
In other news and on the subject of evolutionary psychology here’s a really fun and ridiculously geeky thing I found:
Hello! This is my first post here at Replicated Typo and I thought I’d start with reposting a slightly modified version of a three-part series on the evolution of the human mind that I did last year over at my blog Shared Symbolic Storage.
So in this and my next posts I will have a look at how human cognition evolved from the perspective of cognitive science, especially ‘evolutionary linguistics,’ comparative psychology and developmental psychology.
In this post I’ll focus on the evolution of the human brain.
Human Evolution
We are evolved primates. (As are all other primates of course. So maybe it is better to say that we, like all other primates, are evolved beings with a unique set of specializations, adaptations and features. )
In our lineage, we share a common ancestor with orangutans (about 15 million years ago (mya)), gorillas (about 10mya), and most recently, chimpanzees and bonobos (5 to 7 mya). We not only share a significant amount of DNA with our primate cousins, but also major anatomical features (Gazzaniga 2008: 51f., Lewin 2005: 61) These include, for example, our basic skeletal anatomy, our facial muscles, or our fingernails (Lewin 2005: 218ff.).
What most distinguishes us as humans on an anatomical level are our bizarre hair distribution, our upright posture and the skeletal modifications necessary for it, including a propensity for endurance running, our opposable thumbs, fat deposits that are unusually extensive (Preuss 2004: 5), and an intestinal tract only 60% the size expected of primates our size (Gibbons 2007: 1558).
Finally, there is also a distinguishing feature that is a much more remarkable violation of expectations – a brain three times the size expected of a primate our size. This is all the more interesting as primates are already twice as encephalized as other mammals (Lewin 2005: 217). A direct comparison shows this difference in numbers: Whereas human brains have an average volume of 1251.8 cubic centimetres and weigh about 1300 gram, the brains of the other great apes only have an average volume of 316.7 cubic centimetres and weigh between 350-500 gram (Rilling 2006: 66, Preuss 2004: 8). In a human brain, there are approximately a hundred billion neurons, each of which is connected to about one thousand other neurons, comprising about one hundred trillion synaptic connections (Gazzaniga 2008: 291). If you would count all the connections in the napkin-sized cortex alone, you’d only be finished after 32 million years (Edelman 1992: 17).
Expensive Tissue
The human brain is also extremely “expensive tissue” (Aiello & Wheeler 1995): Although it only accounts for 2% of an adult’s body weight, it accounts for 20-25% of an adult’s resting oxygen and energy intake (Attwell & Laughlin 2001: 1143). In early life, the brain even makes up for up 60-70% of the body’s total energy requirements. A chimpanzee’s brain, in comparison, only consumes about 8-9% of its resting metabolism (Aiello & Wells 2002: 330). The human brain’s energy demands are about 8 to 10 times higher than those of skeletal muscles (Dunbar & Shultz 2007: 1344), and, in terms of energy consumption, it is equal to the rate of energy consumed by leg muscles of a marathon runner when running (Attwell & Laughlin 2001: 1143). All in all, its consumption rate is only topped by the energy intake of the heart (Dunbar & Shultz 2007: 1344).
Consequently, if we want to understand the evolutionary trajectory that led to human cognition there is the problem that
“because the cost of maintaining a large brain is so great, it is intrinsically unlikely that large brains will evolve merely because they can. Large brains will evolve only when the selection factor in their favour is sufficient to overcome the steep cost gradient“ (Dunbar 1998: 179).
This is especially important for people who want to come up with an “adaptive story” of how our brain got so big: they have to come up with a strong enough selection pressure operative in the Pleistocene “environment of evolutionary adaptedness” that would have allowed such “expensive tissue” to evolve in the first place (Bickerton 2009: 165f.).
What About the Brain is Uniquely Human?
If we look to the brain for possible hints, we first find that presently, there is “no good evidence that humans do, in fact, possess uniquely human cortical areas” (although the jury is still out) (Preuss 2004: 9). In addition, we find that there are functions specific to humans which are represented in areas homologous to areas of other primates. Instead, it seems that in the course of human evolution some of the areas of the brain expanded disproportionally, “especially higher-order cortical areas, including the prefrontal cortex” (Preuss 2004: 9, Deacon 1998: 435-438). This means that humans are not simply ‘better’ at thinking than other animals, but that they think differently (Preuss 2004: 7). The expansion and apparent specializations of only certain kinds of neuronal areas could indicate a qualitative shift in neuronal activity brought about by re-organization of existing features, leading to a wholly different style of cognition (Deacon 1998: 435-438 Rilling 2006: 75).
This scenario squares well with what we know about the way evolution works, namely that it always has to work with the raw materials that are available, and constantly co-opts and tinkers with existing structures, at times producing haphazard, cobbled-together, but functional results (Gould & Lewontin 1979, Gould & Vrba 1982). Given the relatively short time span for the evolution of the “most complex structure in the know universe”, as it is sometimes referred to, we have to acknowledge how preciously little time the evolutionary process had for ‘debugging.’ It could well be that make the human mind is so unique because it is an imperfect ‘Kluge:’ “a clumsy or inelegant – yet surprisingly effective – solution to a problem,” like the Apollo 13 CO2 filter or an on-the-spot invention by MacGyver (Marcus 2008: 3f.). It may thus well turn out that what we think makes us so special is a mental “oddity of our species’ way of understanding” the world around us (Povinelli & Vonk 2003: 160). It is reasonable then to assume that human cognition did not just simply get better across the board, but that instead we owe our unique style of thinking to quite specific specializations of the human mind.
With this in mind, we can now ask the question how these neurological differences must translate into psychological differences. But this is where the problem starts: Which features really distinguish us as humans and which are more derivative than others? A true candidate for what got uniquely human cognition off the ground has to pass this test and solve the problem how such “expensive tissue” could evolve in the first place.
In my next post I will have a look at six candidates for what makes human cognition unique.
References:
Aiello, L., & Wheeler, P. (1995). The Expensive-Tissue Hypothesis: The Brain and the Digestive System in Human and Primate Evolution Current Anthropology, 36 (2) DOI: 10.1086/204350
Aiello, L., & Wells, J. (2002). ENERGETICS AND THE EVOLUTION OF THE GENUS HOMO Annual Review of Anthropology, 31 (1), 323-338 DOI: 10.1146/annurev.anthro.31.040402.085403
Attwell, David and Simon B. Laughlin. (2001.) “An Energy Budget for Signaling in the Grey Matter of the Brain.” Journal of Cerebral Blood Flow and Metabolism 21:1133–1145.
Bickerton, Derek (2009): Adams Tongue: How Humans Made Language. How Language Made Humans. New York: Hill and Wang.
Deacon, Terrence William (1997). The Symbolic Species. The Co-evolution of Language and the Brain. New York / London: W.W. Norton.
Dunbar, Robin I.M. (1998): “The Social Brain Hypothesis Evolutionary Anthropology 6: 178-190.
Dunbar, R., & Shultz, S. (2007). Evolution in the Social Brain Science, 317 (5843), 1344-1347 DOI: 10.1126/science.1145463
Edelman, Gerald Maurice (1992) Bright and Brilliant Fire: On the Matters of the Mind. New York: Basic Books
Gazzaniga, Michael S. (2008): Human: The Science of What Makes us Unique. New York: Harper-Collins.
Gibbons, Ann. (2007) “Food for Thought.” Science 316: 1558-1560.
Gould, Stephen Jay and Richard Lewontin (1979): “The spandrels of San Marco and the Panglossian paradigm: a critique of the adaptationist programme.” Proclamations of the Royal. Society of London B: Biological Sciences 205 (1161): 581–98.
Gould, Stephen Jay, and Elizabeth S. Vrba (1982), “Exaptation — a missing term in the science of form.” Paleobiology 8 (1): 4–15.
Lewin, Roger (2005): Human Evolution: An Illustrated Introduction. Oxford: Blackwell.
Marcus, Gary (2008): Kluge: The Haphazard Evolution of the Human Mind. London: Faber and Faber.
Povinelli, Daniel J. and Jennifer Vonk (2003): “Chimpanzee minds: Suspiciously human?” Trends in Cognitive Sciences, 7.4, 157–160.
Preuss Todd M. (2004): What is it like to be a human? In: Gazzaniga MS, editor. The Cognitive Neurosciences III, Third Edition. Cambridge, MA: MIT Press: 5-22.
Rilling, J. (2006). Human and nonhuman primate brains: Are they allometrically scaled versions of the same design? Evolutionary Anthropology: Issues, News, and Reviews, 15 (2), 65-77 DOI: 10.1002/evan.20095
Back to the future on syntax and Broca’s area. Talking Brains provide a concise and humorous post about why Broca’s area is not the seat of syntax, be it domain-specific or domain-general. I tend to think that areas important for syntactic processing are probably distributed throughout the left perisylvian region. Hence why Broca’s aphasiacs are quite capable of making grammatical judgements. Then again, another reason why damage to Broca’s area doesn’t, to quote Hickok, “obliterate the ability to make such judgements”, is because the processing shifts to another region (sort of an ancillary system). This is very possible in the advent of neuroplasticity.
Neuroplasticity is a dirty word. Having mentioned neuroplasticity, I now feel obligated to mention this brilliant post over at Mind Hacks. It provides a sort of 101 approach to neuroplasticity, which, after all, simply means something in the brain has changed. Still, as one poster from Ethnographer.com pointed out: “However, at its most abstract, the concept of neuroplasticity is often arrayed against that other commonplace abstract notion, that the brain is genetically ‘hard-wired’ in some way”.
Dialect Geography and Social Networks. Mark Lieberman over at Language Log discusses geographical patterns of linguistic variation and recent analyses of facebook networks in the US. Put succinctly: they don’t line up very well. He also asks some interesting questions about the role facebook might play as a proxy for communication patterns.
How best to learn R. R is an invaluable statistical package. If, like me, you find yourself being dropped in at the deep end, then things can seem slightly confusing in an environment that is far less user friendly than, say, SPSS. All the important stuff is in the comments section of the post, but you should take some time out to have a general poke around Statistical Modelling, Causal Inference and Social Science.
Are Scottish People Living Dangerously? The short answer: Yes. Barking Up The Wrong Tree links to a study claiming that “Almost the entire adult population of Scotland (97.5%) are likely to be either cigarette smokers, heavy drinkers, physically inactive, overweight or have a poor diet.”
The Sun Gone Crazy? Apparently, for the past two years there’s been a prolonged absence in sunspots. But as Adam Frank mentions, “The magnetic activity of stars like sun, which is the root cause of the sunspot cycle, is still poorly understood even after decades of intense study. It’s more than an academic concern”.
Three Questions for Michael Tomasello. A cool little interview with the chimpanzee, linguistic and cooperation guru, Michael Tomasello, over at cognition and culture.
Having now returned, I feel a long list of links is needed to kick start things:
Right, that’s all I’ve got time for at the moment. Laptop battery is dying and my bladder is urging me towards the toilet.
