Bruce Hood - The Domesticated Brain - A Pelican Introduction (Pelican Books)

The psychologist Nick Humphrey has suggested that it would be more appropriate to call our species Homo psychologicus (psychological man), given the ability of Homo sapiens to read minds – not in any supernatural psychic way, but simply by imagining what someone else is thinking and predicting what they may do next. 37You need to be able to read others if you are a member of a species that has evolved to co-exist and, more importantly, cooperate. You also need these skills if you are producing helpless infants who need childcare and shared rearing. In order to make sure that you have enough resources for yourself and any offspring, you must be able to understand and anticipate the intentions and goals of other members of the group.

This is particularly true of primates who engage in deception and coalition formation, sometimes called ‘Machiavellian intelligence’ after the Italian Renaissance scholar who wrote about how to govern through cunning and strategy. 38This ability requires a set of social skills known as ‘theory of mind’ in the psychological literature and represents a powerful component of social intelligence. 39When you have a theory of mind, you are able to mentally put yourself in another’s shoes to see things from their perspective. This enables you to keep track of others, to second-guess their intentions, to outwit them and to exchange ideas. As we will read in later chapters on child development, theory of mind has a protracted progress and for some unfortunate individuals remains impaired, which presents a considerable hurdle in communicating with others.

The chattering brain

One uniquely human social skill that we regularly use for problem solving is language. Although we sometimes talk to ourselves, the primary purpose of language is to communicate with others. We learn to speak by listening to others, and if we were raised in an environment where we heard no language, then all the evidence indicates that we could not learn to speak normally at a later age, no matter how much training and effort we put in. There is something in our biology that dictates that we must be exposed to language at a critically early age to acquire it. 40Even learning a second language becomes increasingly harder as we age, indicating that there is a biological window of opportunity for language acquisition.

Just about every facet of human activity involves language, whether it is work, rest or play. No other animal on the planet communicates like we do. They may have squawks, barks, grunts, squeals, snorts, screams, cries, hoots and all manner of noises, but the information they are communicating is extremely limited and rigid. Despite what Walt Disney and other animators would like us to believe, animal communications are nothing more than elaborate signalling systems to convey one of four simple messages:

‘Watch out, there’s trouble about.’

‘Back off, man, I mean business.’

‘Come and get it, there’s food over here.’

Or more often than not,

‘Come and get it, ladies, I’m over here.’

Animal communication is primarily for the four Fs of fleeing, fighting, feeding and fornicating – basic drives that keep us alive long enough to pass on our genes by reproduction. Humans also spend a considerable amount of time communicating on these very topics but when we communicate, there is nothing we better like to do than talk about others. An analysis of typical conversations in a shopping mall revealed that two thirds of the content was related to some social activity – who’s doing what with whom. 41Human communication is not restricted to biological drives that are necessary for survival and reproduction. We can talk about the weather, politics, religion and even science. We can pass on opinions, instructions and all manner of other high-level, complex information, though in all likelihood our initial communications when language first appeared were probably directed to the same four Fs that were necessary for survival. After all, human communication is complicated and difficult to execute and therefore must have evolved for a good purpose. 42

Why can’t we talk with the animals? First, we are the only primates with the motor machinery that enables us to vocalize the controlled sounds that form the building blocks of speech. 43Most notably, unlike other primates, we have a descended larynx. The larynx or ‘voice box’ serves a number of roles. As we exhale, the air passes by the vocal cords that vibrate to create sound in the same way that blowing across a blade of grass produces a quacking sound. Changing the shape of the mouth, tongue and lips as well as controlling our breathing can further modify these sound segments to produce the differing vocalizations. The other main role of the larynx is to close up in order to protect us from inhaling food, but it does not begin to descend in the human until around three months of age, which explains why babies can swallow and breathe at the same time when they are breastfeeding.

With our descended larynx, we have a much longer vocal tract, enabling us to produce a much greater variety of sounds. Coupled with this extra-long sound pipe, we also have greater muscular control over our lips and tongues compared to other primates, which is why human speech is physically impossible for other animals. But that physical limitation is not the only reason that animals do not speak. They simply don’t have the right brains for it. Karl Lashley, the American psychologist, originally proposed in 1951 that the unique basis of human speech must involve brain circuitry responsible for sequencing movements. 44In recent years, this hypothesis has gained support from the discovery of the FOXP2 gene that governs the embryonic development of brain structures that support speech production. Even if animals could control the required movements, linguist Noam Chomsky emphasizes decoding the underlying structure of language itself as requiring specialized brain mechanisms that humans alone have evolved. 45The major difference between our language and the social communication of other animals is that we have a system of grammar – words and rules that can combine together to generate an unlimited number of new sentences about anything. Most of us are not even aware that we are using these rules. As native speakers, we can spot that there is something wrong with the utterance ‘complex human is language’ because it does not follow the rules, but very few of us know exactly what these rules are. Before we discovered the rules of language, humans were speaking grammatically.

Language is also a symbolic system, which means we use sounds to stand for something. In speech these are the words, but before there were words there must have been specific sounds that we learned to associate with meaning. Animals can also learn to associate sounds to stand for things if they are trained to do so. They can even learn to associate gestures with meanings. There are some famous cases of chimpanzees that learned sign language, but this is not something they can do spontaneously. It requires lots of training with rewards and they cannot make up new sentences as easily as children do.

There is something special about human language in both production and understanding that other animals just do not get because it was never part of their evolution. Our capacity for language is arguably the major species-specific ability that catapulted modern humans into an unparalleled league of social interaction. It has not always been like this. A hunter-gatherer ancestor did not wake up one day and blurt out to the rest of the tribe, ‘Let’s go hunting.’ Our language must have evolved into the complex behaviour that is universally enjoyed today. Some argue that evolution cannot explain something as complex as language but it is precisely because of that complexity that language had to evolve gradually by natural selection. In the same way that the eye is a complex biological adaptation that could not have suddenly appeared from a one-off mutation, the same must be true for language.