Chapter 2 – Language as a biological adaption

Wikis > Chapter 2 - Language as a biological adaption

2014: Leong Kai Ting, Cassandra Ong Xian Bin, Sean Tse Mun Hin

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1. Biological Adaption

In recent years, there has been increased interest in human language and the evolution of language. A few important questions have been raised as a result: Why have humans managed to acquire language while animals remain contented with their communication systems? Why are animals unable to acquire language even if they are taught the language?

Biological adaptation has been proposed as a possible explanation for language presence in humans and absence in animals. This chapter aims to explore language and biological adaptation in greater detail.
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2. Literature Review

Language evolutionists are split over the application of the Darwinian Theory of natural selection in the explanation of language evolution. It was put forth by Pinker & Bloom (1990) that human language may have evolved by a process of biological natural selection. The human language system and its intricate cognitive requirements are explained by the development of the human brain and other organs of great complexity as a means of natural selection. Furthermore, the design features of language analysed as part of language evolution research suggest that human language is a product of natural selection, and its evolution has then enhanced humans capacity to communicate and socialise interdependently (Pinker, 2003).

The archaeological research of the Neanderthal fossils and genes also further provide evidence for a proto-language between the Neanderthal and humans with common lexical semantics (Johansson, 2013). Despite the indisputable fact that humans have language and speech while other non-human species do not, the discovery of the new DNA evidence shows a relationship between the Neanderthal and humans. This reaffirms the strong relevance of natural selection in the study of language evolution.

There are however also arguments and disagreement with the application of the Darwinian theory in the explanation of language systems used by humans and animals. Penn, Holyoak & Povinelli (2008) remarked that the differences between humans and non-humans have been downplayed, claiming that there is a lack of continuity in the approximation of complex, “systematic relational capabilities of a physical symbol system”. They also attempted to further show that this lack of continuity is also exhibited in every other domain of cognition in humans and has an intricate structure that cannot be merely explained by the prevalence of language and culture of humans. This complexity is perceived to be the difference that would mark humans from non-humans, against the Darwinian theory of gradual evolution. However, Burghardt (2008) disagrees with their argument as he finds it problematic the authors ignored the relevance of semantics in human language. Herman, Uyeyama and Pack (2008) contested the authors’ claim that the functional differences between human and non-human using the evidence of bottlenose dolphins’ relational capabilities.

In this wikichapter, Theory of Mind and functions of the FOXP2 gene are examined in relation to the explanation of language being a biological adaptation.
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3. Theory of Mind (ToM)

One of the more compelling arguments proposed, is language and the theory of mind. Theory of mind (TOM) refers to the cognitive ability to represent, conceptualize and reason about mental states. In this retrospect, the ability to identify behavioral patterns or the ability to make sense of the minds of others is also considered TOM. The TOM is a trait unique to humans, though in recent studies, researchers have found that certain apes are seen to be on the brink of developing their own TOM.

As conceptual framework, TOM is the reason for the cognitive aspect of human behavior. This framework treats perceptual input as perceptual stimuli – classifying it as a belief or an intentional action warranting response. The framework further dictates appropriate response to such perceptual stimuli – in the form of inference, prediction and explanation.

Theory of Mind is not present in humans from the start – rather the cognitive framework is slowly honed as the child grows into adulthood. At different ages, there is a change in the developmental stage of TOM in humans. Miller (2006) crafted a table that outlined a timeline for the development of different aspects of theory of mind, which can be seen below.

tom1

Past research has shown that there is a significant development in TOM between the ages of 3 to 4 years old. At the stage of early concept formation (between infancy to 2 years of age), there is a consistent development of TOM in children in different areas: perceptual sensitivity to goal-directed action and the ability to infer intention from human behavior. After which, the TOM sees a development in the conceptual understanding of desire and belief (between 2 to 3 years of age). The conceptual understanding of false belief is developed at 4 years of age.

The ability to understand false beliefs is commonly attributed as the significant milestone in the development of TOM. This is why there is a significant development in TOM as a child turns 4, since the child now is able to differentiate false beliefs from beliefs. There is a simple task used to test whether a child has achieved this conceptual understanding, also known as the false beliefs task.

In this task, the child is given the following scenario:A boy leaves chocolate on a shelf and then leaves the room. His mother puts it in the fridge. The child would be tasked to identify whether the boy would look first for the chocolate when he returns to the room. To pass the task, the child must understand that the boy holds the false belief that his chocolate is still on the shelf and would look there first, instead of heading for the fridge. By passing the false beliefs test, it shows that the child is able to understand that his own mental representation of the situation is different from the mental representation of another, and the child should predict the behavior of another accordingly, based on their mental representation.

It has been observed that as a child grows older, the instances in which they are able to accurately predict the behavior of another through the false beliefs test increases. At age 4, the likelihood for them to be able to identify the correct location of the chocolate would increase, compared to when they were three years old.
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3.1 Language and TOM

Grammar has been assumed to be the fundamental characteristic that made language unique. Grammatical form codes speech and utterances in different basic structures – the most common being SOV, SVO or OVS. As seen in the three structures, there are different ordering to the Subject, Verb and Object agreement. Yet across the three different structures, there remains a generic structure: the agent, the recipient and the action would need to be present in each sentence regardless of the structure used.

Recent studies have shown, however, that the theory of mind has played a larger role in the evolution of language, compared to grammar. Language could not have evolved without the affiliated evolution of TOM in humans. There would be communication – even grammatical communication – but all these would simply be factual statements without any human emotion injected into the speech, somewhat like robot speech (Malle, 2004).

Miller (2006) raises some key issues regarding the complexity of the relationship between language and TOM. In order for successful communication to happen, it is essential for the speaker to have an awareness of mental states. Language is, thus, one of the key mechanisms used to express the different aspects of TOM.

Consider the following scenario:

A child points at a tree and says, “Look at that tree mummy!”

His mum asks, “What colour is the tree?”

The young boy replies, “Green!”

The above scenario shows how language can be used to express different aspects of TOM. In the very first sentence when the child points out the object, he attempt to use language to create joint attention. Here, his mother’s attention would be directed to the object that he is referring to. His mother’s reply in the second sentence is indication of this joint attention, because she acknowledges the object, and goes on further to ask him to clarify some characteristics of the object. In this sentence, the mother crafts a sentence to create communicative intent for her son to continue the conversation. The young boy’s reply in the third line is clear that the boy recognizes communicative intent presented in his mother’s question, and that is an aspect of TOM demonstrated.

As seen above, language and TOM is linked and some researchers have been concerned with identifying the possible links between the two, and they have proposed different schools of thoughts regarding the link between language and TOM.
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3.2 Schools of thought

Evidently, there is some form of correlation between language and theory of mind. Drawing attention back to the table outlining the development of theory of mind in a child, it is clear that as the theory of mind is developing, the child is acquiring language at the same time (all this is under the presumption that the child is not suffering from any form of disability, like Autism or Deafness).

With this correlation in mind, many evolutionists have been fascinated with the order with which language or theory of mind came about. Was it language that preceded theory of mind, or vice versa? Or did they both co-evolve at the same time? Perhaps there may have been other factors involved in the evolution process.

For this chapter, we are concerned with two schools of thought proposed by researchers:TOM precedes language and language precedes TOM. We would then conclude and propose our own school of thought based on the findings of researchers in the previous schools of thought.
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3.2.1 TOM precedes language

Malle (2004) highlights the importance of TOM, beyond the ability to understand and predict mental states of oneself and others. His stance regarding this school of thought is that “language acquisition itself appears to rely on theory of mind skills”. This argument is key in exemplifying why TOM needs to be present before any language acquisition can happen, and thus development of TOM precedes language.

Joint attention, as seen in table 1, refers to the ability to register the fact that the self and others are attending to the same object at the same time (Bruinsma et al,. 2004; Carpenter et al., 1998). Joint attention is the first aspect of TOM that is developed, when the child is between 6-12 months old. Past research has indicated the importance of joint attention in the development of TOM and the subsequent influence joint attention has on the ability for one to pick up language. The development of joint attention, would be essential for language acquisition especially in early word learning, grammatical development and referential communication.

Children suffering from autism have been known to suffer from deficits in joint attention, and that has resulted in difficulties in language learning and a subsequent deficit in their communicative abilities. In other children that may suffer from other mental handicap or general cognitive deficits, yet have a developed joint attention, they still manage to acquire language much better than children suffering from autism.
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3.2.2 Language precedes TOM

The strongest argument for language preceding TOM would be the approach De Villers (2001) took, that language acquisition would have a significant impact on TOM development. In order to prove this, De Villers looked at language delay, and how a delay in the acquisition of language would perhaps cause a slower rate in developing certain aspects of TOM.

To better test this theory, would be to look at the acquisition of deaf children and their TOM development. Deaf children would typically experience a delay in acquiring sign language, especially when they are born to speaking parents, that may be unable to sign with their children from day one. Studies have shown that deaf children with delayed language input would experience a delay in their reasoning of other’s mental states (de Villers, 2001). At the same time, when comparing deaf children that have delayed language input versus deaf children who acquire sign language from an earlier age (because their family members are able to provide sign input from young), it is apparent that the former are less developed in TOM compared to the latter. With regards to false beliefs, deaf children with deaf parents are not delayed in this TOM aspect, compared to deaf children with hearing parents.

While this shows how language acquisition plays an important role in the development of TOM, there is a flaw. The aspects that the researchers have been testing at this stage, are mostly on how language acquisition affects false beliefs development, which is developed when the child is 49-60 months. This does not address how language precedes TOM, since delayed language input seems to affect only later stages of TOM and not the earlier stages.

Here, it appears that a possible resolution would be that TOM influenced language in the earlier years. In the later years, language would in turn affect the development of the later stages of TOM. Malle (2004) suggests that after language has been developed to a mature level, language itself becomes autonomous from TOM, and the linguistic mastery the child possesses would be used to refine TOM skills in the later part of childhood and early adolescence.
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3.2.3 Our School of thought

Having looked at both schools of thought, we have decided that TOM influences language. In order for language acquisition to happen in children, it is necessary for the children to have theory of mind. However, at a certain age, language becomes autonomous from TOM and can overcome any form of deficits in TOM if present. Even as language becomes autonomous from TOM in the later years, TOM remains a factor that influences language.

In language acquisition, it is clear that TOM has influenced protolanguage and enabled the development of the protolanguage to language. The bulk of this chapter has focused on TOM and its influence on language, in terms of language acquisition in children. The question remains, however, how does TOM shape the evolution of language?

Beyond the area of acquisition, it appears that even in the evolution of TOM and the evolution of language, TOM evolves first, and it leads to the subsequent evolution of language from protolanguage to language. Malle’s (2004) proposed chain of model as seen below, is a model that we would advocate as well.

protolanguage → TOM → language

Malle (2004) proposes the emergence of a primitive theory of mind (TOM-1) as the first adaptive step, on which any form of language learning can be acted upon. At the primitive level of TOM-1, the features that developed at this stage are:

Our School of thought

These features of TOM-1 is similar to the first three stages of TOM development in infants, before 12 months old. Here, Malle speculates that while these stages are developed within 12 months in acquisition, the evolution of these features of TOM-1 would have been separated by a few million years, in the hominid self.

Here, imitation and joint attention could initiate cooperative learning, while joint attention and sensitivity could improve behavior prediction and coordinate shared activities – hunting and tool-making activities that were evident in the hominids. These three elements of TOM-1 would thus become the framework upon which protolanguage could act upon, with expressive vocalization and gestures being used at this stage to refer to certain objects or goals. At the same time, the presence of these three elements leads to communicative interactions between hominids. Hominids can imitate each others vocal projections through imitation, vocal reference can be reinforced through joint attention and inferential sensitivity would see hominids inferring vocal references as having some communicative intent. At the primitive stage of TOM-1, it is clear that language has yet to be developed at this stage, with gestures and vocalized expressions used to express TOM.

TOM-2 is the second stage of TOM development. As a result of TOM-1 and proto language, there would be an increase in communication between the hominids . The simplistic nature of the protolanguage (random vocalized expressions and gestures) is likely to have caused difficulties in communication and possible miscommunication among hominids. Referring back to table 1, TOM-2 would have the same features as TOM that is developed in children between 13-24 months. TOM-2 would see the development of the ability to recognize intent expressed by others, and the ability to recognize desires others may have that differentiates from self desires.

At this stage, a more refined TOM would lead to a more developed protolanguage or PL-2. Here PL-2 would be the intermediate stage between the protolanguage and language. For clearer visualization, the development of protolanguage proposed by Malle (2004) would be:

protolanguage → PL-2 → language

At the PL-2 stage, there would be a decrease in the number of gestures used, and an increase in more precise linguistic references used, other than random vocalized expressions. Here, the presence of grammatical distinctions (nouns, verbs, adjectives) is an indication of the referential nature of PL-2 compared to the expressive nature in the previous protolanguage stage.

As observed in the discussion above, it is clear that as the different aspects of TOM are developed in hominids over the years, protolanguage is also being developed at the same time. Thus, in order for language to have developed from a protolanguage, TOM-1 and TOM-2 played essential roles in shaping the the protolanguage and PL-2. Both TOM-1 and TOM-2 have seen a development of different cognitive aspects in the human brain from the time of hominids that has resulted in the subsequent development of the protolanguage to language.

Thus, the evolution TOM is important in shaping the evolution of language from TOM.
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3.3 Evaluations

It seems that the field of TOM has gaping research holes. A great deal of research has been carried out of the TOM development from infants to children aged 7 years old. After the age of 7 years, there seems to be a lack of research carried out testing TOM and language correlations. Thus it would be difficult to come to any conclusion regarding language influencing TOM, since the research thus far have been satisfied with the following conclusion – that language becomes autonomous from TOM.

Here we can look at those who were previously unable to acquire language fully because of the lack of certain aspects of TOM (children suffering from Autism). These children were still able to catch up with their peers, in terms of communication. Here, their linguistic competence would make up for their inability to understand mental states of others, by using complex linguistic representation.
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4. FOXP2

Genes are the basic building blocks for all organisms; these stretches of deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) code for all functional proteins and RNA chains; these proteins and RNA chains are the essential molecules for life. These genes hold important and essential information to maintain an organism’s cells and pass on these genetic traits to their offsprings.

Natural selection is the gradual process through which biological traits become either more or less common in a population as a function of the effect of inherited traits on the differential reproductive success of organisms interacting with their environment. Natural selection is an important concept as it is responsible for shaping the genetic basis of traits, which results in biological adaptation (Pinker & Bloom, 1990).

One compelling, yet controversial, theory proposed is the Forkhead box protein P2 (FOXP2) gene and the role it possibly plays with reference to human language. The FOXP2 protein is encoded by the FOXP2 genes in humans and it many studies have shown that it plays an important role, albeit unclear, in proper speech and language development.

There are a few FOXP2 studies examined in this wikichapter, along with an evaluation and a summary of the gene’s origins.
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4.1 Origins of FOXP2

The identification of the FOXP2 gene can be traced back to  the study of the KE family, a British family of Pakistani origin, where about half of them had exhibited a speech order called developmental verbal dyspraxia (DVD) (Hurst, Baraitser, Auger, Graham & Norell, 1990). DVD is a motor disorder which results in the inability of utilizing one’s motor control to carry out proper movements for speech during a child’s language learning stage. The Hurst et al. (1990) study had observed that approximately half of the KE family had been suffering from DVD over three generations. It is then concluded that the this condition was genetically inherited.

Media exposure of the KE family had led to the paper written by Myrna Gopnik (1990), who was at the time travelling in Britain. In her study, she had collected and analysed utterances from individuals suffering from DVD. Gopnik (1990) had hypothesised that the disorder affects not just general language performance, but specifically the usage of grammar. This led to a popular promotion of the term “grammar gene” and also the position of a possible grammar-specific genetic disorder, which are considered very controversial. However, this hypothesis was subsequently disproved by study in 1995, which had concluded that the disorder not only impairs linguistic ability, but also intellectual and physiological features; this effectively invalidates the “grammar gene” notion. (Vargha-Khadem, Watkins, Alcock, Fletcher & Passingham, 1995)

In 1998, a study by Oxford University geneticists Fisher, Monaco, Lai, Hurst, and Vargha-Khadem observed the distribution samples of DNA of members from the KE family and they had concluded that the inheritance of DVD was related to a region within Chromosome 7. By 2001, through various methods of analysis, Fisher et al. (2001) had identified that the mutation which may have influences upon DVD inheritance is in a gene located within Chromosome 7. Further analysis led them to discover that the gene codes for a protein belonging to the forkhead box protein family, leading them to name it FOXP2.
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4.2 Other relevant studies

Besides the observations conducted on the KE family, there are also other studies related to the FOXP2 gene and its purported link to language evolution. Various animal studies have been conducted to observe the possible effects of the FOXP2 in organism other humans. These studies usually utilize the technique of “knocking out” (in which genes are rendered non-functional) or “knocking down” (in which gene expression is reduced) genes so as to observe any resulting effects due to the absence or the reduction in expression of a particular gene. This can lead to further understanding of the function of a particular gene by a comparison with organisms with normal functional genes. A study conducted on zebra finches (a type of songbird) had shown that FOXP2 expression increases in the Area X region of its basal ganglia. By knocking down FOXP2 in these songbirds, it can be observed that there is inaccurate and incomplete imitation of a song. The abnormality of song learning by these birds have also been compared to the learning of words by children afflicted with DVD. (Haesler, Rochefort, Georgi, Licznerski, Osten & Scharff, 2007)
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4.3 Evaluations

The FOXP2 gene was thereafter used to examine the history of language evolution through the understanding and analysis of language impairments. That said, there remains two issues unresolved; that is, the link between FOXP2 and human languages is still inconclusive.

The discovery of FOXP2 was through the analysis of the DVD, which itself is widely considered to be an umbrella term for several other language disorders. The KE family would certainly not be affected by the entire array of language disorders, and thus the attempt to link the FOXP2 to human languages may be problematic. Secondly, there is also a lack of complete understanding of the FOXP2, and its function, especially pertaining to the acquisition and management of human languages. FOXP2, being a transcription gene, activates a number of other genes instead of operating within a structure of its own, also makes it difficult to attribute its effects on other genes, and its own functions to the human language. Therefore, even when it is popular to sell the theory that the FOXP2 can potentially be linked to the human-ape differences and not just language evolution, it is still commonly agreed that until it can be clearly established how the FOXP2 can be turned on and off, it is premature to claim the FOXP2 has direct links with language. (Bickerton, 2007).
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5. Conclusion

This chapter has dealt with language as a biological adaptation driven by natural selection processes. It has also evaluated theories and evidence in support. The two main theories dissected were the Theory of Mind, and the FOXP2 gene, and the funtions of the FOXP2 gene. This chapter also showed that Malle’s model is able to clarify many doubts in language evolution and also strengthened the theory of protolanguage. Theory of Mind’s compatibility with grammar provides a strong explanation for the complexity of today’s human language system. The study of FOXP2 will also help unlock a lot of doubts about the role of genes in the evolution of language. However, there is uncertainty of the function of FOXP2 itself, given that it is a transcription gene, and further research is needed. Therefore the Theory of Mind as explained by the Malle’s Model still winds up as the more compelling argument in this chapter.
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References

Bickerton, D. (2007). Language evolution: A Brief guide for linguists. Lingua, 117, 510-526.

Bruinsma, Y., Koegel, R. L., & Koegel, L. K. (2004). Joint attention and children with autism: A review of the literature. Mental Retardation and Developmental Disabilities, 10, 169–175.

Carpenter, M., Nagell, K., & Tomasello, M. (1998). Social cognition, joint attention, and communicative competence from 9 to 15 months of age. Monographs of the Society for
Research in Child Development, 63(4), Serial No. 255.

de Villiers, J. G., & de Villiers, P. A. (2003). Language for thought: coming to understand false beliefs. In D. Gentner & S. Goldin-Meadow (Eds.), Language in Mind: Advances in the Study of Language and Thought (pp. 335-383). Massachusetts: MIT Press.

Fisher, S.E., Vargha-Khadem, F.,Watkins, K.E., Monaco, A.P. & Pembrey, M.E. (1998). Localisation of a gene implicated in a severe speech and language disorder. Nature-Genetics 18 (2): 168–170.

Haesler S., Rochefort C., Georgi B., Licznerski P., Osten P., & Scharff C.(2007) Incomplete and inaccurate vocal imitation after knockdown of FoxP2 in songbird basal ganglia nucleus area x. PLoS Biology 5(12) 2885-2897Johansson, S. (2013). The Talking Neanderthals: What Do Fossils, Genetics and Archeology say? Biolinguistics, 7, 35-74.

Lai C.S. Fisher S.E., Hurst J.A., Vargha-Khadem F. & Monaco A.P. (2001) A forkhead-domain gene is mutated in a severe speech and language disorder. Nature 413(6855): 519–23

Malle, B. F. (2004). The relation between language and theory of mind in development and evolution. In T. Givon & B. F. Malle (Eds.), The evolution of language out of pre-language (pp. 265-284). Amsterdam: Benjamins.

Miller, C. A. (2006). Development relationships between language and theory of mind. American Journal of Speech-Language Pathology, 15, 142-154.

Pinker, S. (2003). Language as an adaptation to the cognitive niche. In S. Kirby & M. Christiansen (Eds.), Language evolution: States of the Art, (pp. 16-37). New York: Oxford University Press.

Pinker, S., & Bloom, P. (1990). Natural Language and Natural Selection. Behavioural and Brain Sciences, 13(4), 707-784.

Penn, D. C., Holyoak, K. J., & Povinelli, D. J. (2008). Darwin’s Mistake: Explaining the discontinuity between human and nonhuman minds. Behavioural and Brain Sciences, 31, 109-178.
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