Language and Theory of Mind

Introduction
In an article written by Michael Corballis (2004), autonomous speech is considered as a critical factor in how humans became modern. The article focuses on the development of language from one that was dependent on manual and facial gestures to one that is autonomously vocal. But is autonomous speech no longer dependent on manual and facial gestures and completely autonomous? To answer this question one must look closely at the origins of modern language and the interwoven relationships involved in language acquisition. A possible alternative to Corballis’ (2004) theory of autonomous speech is the theory that modern language is still dependent on manual and facial gestures; however mental evolution created an interwoven relationship between language, a secondary representation and covert imitation. The present meta-analysis examines literature that explains how human cognition is different from nonhuman animals in an attempt to find the missing link in cognition that led to the evolution of language.

Origins of Language
It is believed that modern language began with a primitive use of symbols without grammatical structure called protolanguage (Bickerton, 1995, as cited in Corballis, 2004). “Protolanguage is roughly equivalent to the level of language demonstrated by a 2-year-old child or a person with Broca’s aphasia” (p.544). Corballis (2004) makes a distinction between the evolution of language and the evolution of speech. He states that the evolution of language began with the mirror neurons. In monkeys the mirror neurons are located in area F5, which is equivalent to the area of the human brain known as the Broca’s area. The mirror neurons in monkeys were shown to respond not only when the monkey makes a particular movement but also when it observes the same movement performed by another monkey (Rizzolatti, Fadiga, Gallese, & Fogassi, 1996, as cited in Corballis, 2004). But the mirror neurons in humans are different.
The mirror neurons in humans are not object dependent (Rizzolatti et al., 2001; as cited in Corballis, 2004) and may reflect a more abstract representational system. The mirror neurons are predominantly left hemispheric, as is the control of speech and are shown to be active when people “read” speech from facial gestures. The mirror neurons in humans would have the ability to interpret gestures into audible sounds, which could have evolved into words and even complete sentences (Corballis, 2004). But rather than autonomous speech being a human invention, it might have been the result of a genetic mutation.
The FOXP2 gene (forkhead box P2) on chromosome 7 is believed to play a role in incorporating speech into the mirror system of humans. A point mutation on the FOXP2 gene appears to be responsible for a speech and language disorder found in three generations of the KE family (Corballis, 2004). This gene has been called the “grammar gene” (Pinker, 1994, as cited in Corballis, 2004), however, the core deficit was seen in the articulation of phonological units. Further research has shown that subjects who carried the R328X mutation, a “nonsense” mutation on the FOXP2 gene different than the mutation carried by some of the KE family, had severe problems with communication (MacDermot et al. 2005). A closer look at the FOXP2 gene finds no evidence for its role in the evolution of vocal learning in non-humans (Webb, 2005) and found no association between the FOXP2 gene and autistic disorder (Gong et al. 2004), which also shows severe problems with communication. Perhaps the mutation of the FOXP2 gene allows us to examine the relationship between the mirror neurons and the representational skills involved in the evolution of language and theory of mind.
Thomas Suddendorf and Andrew Whiten (2001), explained how “a gradual rise of representational redescription may have made representations ever more explicit, enabled the development of a representational theory of mind, and to invent language” (p. 644). By using Perner’s (1991) representational capacities Suddendorf and Whiten tried to bridge the cognitive gap between humans and our closest relatives. Perner’s three stage model consists of a primary representation, a secondary representation, and a metarepresentation. In the first stage infants are limited to see things in reality. In the second stage children are able to take a primary representation of an object and go beyond reality to model hypothetical situations. A child no longer sees the banana as just a banana; now the banana could represent a phone or a gun. Pretend play becomes very important to the child. The final step in Perner’s representational model is metarepresentation which refers to representing a representation as a representation (Perner, 1991, as cited in Suddendorf et al., 2001). Theory of mind would only appear as a result of acquiring metarepresentations. Rather than focusing on the third stage, Suddendorf and Whiten compared secondary representations of humans with other animals.
Previous studies suggested that theory of mind was built around the pillar of false beliefs (Premack et al, 1978, as cited in Suddendorf, 2001), which would only be available for those animals that are capable of metarepresentations. These studies also showed no evidence of false beliefs in nonhuman primates (Call & Tomasello, 1999, as cited in Suddendorf, 2001). Suddendorf and Whiten (2001) suggest that the acquisition of theory of mind could be better understood through the representational capacities that lead up to a representational theory of mind. Perner’s (1991) secondary representation could also enhance our knowledge of representational capacities that lead up to language acquisition, such as hidden displacement and means-ends reasoning
In Piaget’s hidden displacement task, an object such as a ball is placed under a small box; which is then placed under a larger box. The small box reemerges empty. Perner (1991, as cited in Suddendorf, 2001) argued that in order for a child to pass this stage of object permanence one must not only have a present representation (an empty box), but also have a past or secondary representation of an object in the small box under the larger box. A child would also need to have this ability of representing the present objects as well as the past objects when using language. Perhaps passing a hidden displacement task is the precursor to understanding the causal relationship between present or recent representations objects and representations of objects in the past.
Another example of a secondary representational model is found in means-ends reasoning where one must be able to not only hold a present representation or primary perception in mind; but also a secondary representation of a desired goal. Then one must mentally manipulate the primary representation before acting on the environment (Suddendorf, 2001). Corballis (2004) used this means-end reasoning to explain how autonomous speech allows communication when obstacles intervene between the sender and the receiver. In this way, an object could be mentally represented and shared with another person. Then by sharing a secondary representation of the desired goal, pedagogy could be performed in the dark. However, both the sender and the receiver must be able to hold both representations in mind and mentally manipulate the present object to match the secondary object. But means-ends-reasoning is not only found in humans. There is substantial evidence showing that chimpanzees are able to express means-ends reasoning, as well as some evidence that gorillas and orangutans are able to use means-ends reasoning (Suddendorf, 2001). However, none of these animals have language or theory of mind. Rather than looking at the secondary representation, we need to take a closer look at how the perception of a primary representation is translated into an imitative representational model in the brain.
The Missing Link for Language
In a paper written by Margaret Wilson and Gűnther Knublich (2005), perception and imitation were examined. They found that “various brain areas involved in translating perceived human movement into corresponding motor programs collectively act as an emulator, internally simulating the ongoing perceived movement” (p.468). This emulation could then be used as overt imitation, working memory, or understanding others’ behavior. Their findings suggest that mirror neurons play a substantial role in creating covert imitations of the perceived environment. But the fact that mirror neurons are found in nonhuman primates that do not imitate and do not have theory of mind, leads one to question if the missing link in cognition is at the level of imitation or emulation. To further understand this concept we need to understand how covert imitation functions as an emulator in perceiving conspecifics.
According to Wilson and Knoblich (2005), conspecifics can be thought of as postures and actions primarily of other humans and the movements they make with their arms, legs, facial muscles, and vocal tracts. In humans these conspecifics are “covertly imitated, routinely and automatically” (p.460). One example of this can be seen in the chameleon effect showing the unconscious tendency for people to mimic the behavior of others’ or to mimic a person’s facial expression (Wilson and Knoblich, 2005). Another example of imitation comes from observing infants. “Neonates show imitation of simple facial gestures such as mouth opening and tongue protrusion”(Meltzoff & Moore, 1977; as cited in Wilson and Knoblich, 2005 p.461). Infants also show an ability to connect speech to corresponding motor representations. With these examples in mind, Wilson and Knoblich (2005) suggest that mirror neurons are an evolutionary precursor to imitation allowing humans to learn; understand other peoples’ actions, intentions and goals; and perhaps more importantly to develop a theory of mind. But mirror neurons are not enough to propel nonhuman animals to have greater cognitive abilities.
As mentioned earlier, the mirror neurons are believed to play a part in speech (Corballis, 2004). But nonhuman primates with mirror neurons do not speech or have language. Therefore there must be a second mechanism involved in language processing. “For language to be successful, users must be attuned to the functional equivalence between certain perceived and produced speech forms” and “covert imitation functions as part of a perceptual emulator, using implicit knowledge of one’s own body mechanics as a mental model to another person’s actions in real time” (Wilson, 2005, p.463). A closer look of mirror neurons in monkeys shows that the mirror neurons that respond to a hand grasping an object will also respond if the hand disappears behind a screen. This only happens if the monkey knows that there is an object behind the screen (Umilta et al., 2001; as cited in Wilson, 2005), which could suggest predictive capabilities of mirror neurons. The monkey would have a representation of the primary perception (hand with object) and without seeing the grasping action, activate the same neurons that would be activated if the monkey were to perform the same grasping behavior. Then why can’t monkeys with mirror neurons imitate?
Wilson and Knoblich (2005) state that unlike other animals humans have preexisting resources for representing the body and body movements that are perceived and covertly imitated. Evidence of this can be seen in functional MRI (magnetic resonance imaging) studies that show an activation of motor-related areas of the cortex while the subject observes movement of a hand, arm or mouth (Buccino et al., 2001; Graften, Arbib, Fadiga, & von Cramon, 2003; Rizzolatti et al., 1996; Stevens, Fonlupt, Shiffrar, & Decety, 2000; as cited in Wilson & Bnoblich, 2005). They noted however, that movements that were impossible to imitate did not activate the motor-related areas (Stevens et al., 2000; as cited in Wilson & Knoblich, 2005). Another important fact is that the mirror neurons in humans seem to be active while an action is being imitated (Buccino, Vogt, et al., 2004; as cited in Wilson & Knoblich, 2005). This alone could show that covert imitation in the mirror neuron system played a large role in the evolution of language.
In conclusion, the factors that separate humans from nonhumans are language and theory of mind. But in order to understand how these factors separated us we need to look at the basic mechanisms involved. New research on the FOXP2 gene along with research on imitation and mirror neurons allow science to breakdown language and theory of mind into experimentally tested mechanisms. Rather than viewing language and theory of mind as a philosophical leap of consciousness, science has shown that simple mechanisms such as the ability to imitate motor control would allow humans to learn language through observations. Future studies could show that covert imitation of primary and secondary representations leads to metarepresentations found in theory of mind. The missing link in cognition could be simple covert imitation.















Works Cited

Corballis, M., (2004). The origins of Modernity: Was autonomous speech the critical factor? Psychological Review. Vol. 3, No. 2, 543-552.
Gong, X., Jia, M., Ruan, Y., Shuang, M., Liu, J., Wu, S., Guo, Y., Yang, J., Ling, Y., Yang, X., and Zhang, D. (2004). Association between the FOXP2 gene and autistic disorder in Chinese population. American Journal of Medical Genetics Part B (Neuropsychiatric Genetics). 127B:113-116.
MacDermot, K., Bonora, E., Sykes, N., Coupe, A., Lai, C., Vernes, S., Vargha-Khadem, F., McKenzie, F., Smith, R., Monaco, A., and Fisher, S. (2005). Identification of FOXP2 truncation as a novel cause of developmental speech and language deficits. Am. J. Hum. Genet. 76:1074-1080.
Terrace, H., Metcalfe, J., (2005). The missing link in cognition: Origins of self-reflective consciousness. Oxford University Press. New York.
Webb, D., Zhang, J., (2005). FOXP@ in song-learning birds and vocal-learning mammals. Journal of Heredity. 96(3):212-216.
Wilson, M., & Knoblich, G., (2005). The case for motor involvement in perceiving conspecifics. Psychological Bulletin. Vol. 131, No. 3, 460-473.