Evolution of language

These notes are initially drawn from "The Origins of Language" by James R Hurford

The Prehistory of a Very Special Ape

• 7m years ago - the line leading to humans split off from that leading to bonobos and chimpanzees
• 4-2m years ago - Australopithecus is the first habitually bipedal ape. Bipedalism allowed us to separate the rhythm of breathing from that of walking and running and freed hands for meaningful gestures
• 2.5-1.5m years ago - Homo Habilis (clever man), was the first to make stone tools. This indicates patience, postponement of gratification, a mind capable of foresight into future needs, and constructive planning,
• 1.5m years ago - Homo Erectus, a tall robust ape made more complex tools and may have had a "protolanguage", a meaningful learned vocabulary but no grammar - just words strung together. They made the first migration of hominins out of Africa.
• 1m years ago - Home Erectus can use controlled fire, which allows cooking and reduction of teeth and gut size, which may have freed up resources for bigger brains. These are the first hunter-gatherers, living and working to hunt and forage cooperatively in small groups.
• 500,000 years ago - We diverge from Neanderthals
• 500,000 years ago - Full language? Earliest estimate
• 300,000 years ago - Home Sapiens emerge
• 170,000 years ago - Home Sapiens start wearing clothing - a significant moment in the emergence of culture, clothing carried information about the status of individuals
• 140,000 years ago - Mitochondrial Eve (the most recent woman that all living humans share as an ancestor on their mother's side) and Y-chromosome Adam (the most recent male ancestor that all living men share on their entirely paternal line) are alive.
• 100,000 years ago - Homo Sapiens comes out of Africa
• 70,000 years ago - Settles Asia, Australia
• 40,000 years ago - Settles Europe
• 40,000 years ago - Complex behavior - more refined and task-specific tools, carved and painted art
• 30,000 years ago - Bows and arrows, flutes
• 15,000 years ago - Settles Americas
• 5,000 years ago - A single mother language of the Germanic, Romance, Slavic, and Indic language existed on the boundaries of Europe and Asia.

if any two individuals living today research their family tree, they will find at least one person in common in both trees who was alive at this time

Brain structure and the evolution of language:

• The principal parts of human brains are structurally similar to other ape brains
• Brain size correlates well with the typical size of a social group, with the occurrence of tactical deception, and the complexity of a communication system
• All animals communicate but only humans have the elaborate learned systems that we call language
• There are over 20 major language families on a scale with Indo-European and no proposals as to how they may be historically related
• The rise of human language may have been very fast, but it's hard to imagine it taking less than a few centuries

Nature, Nurture, and Language

• The 'FOXP2' gene is implicated in language
• Humans constructed for themselves a "symbolic niche" and language-fixating genes went to fixation in the human population
• Language has undergone a process of "grammaticalization", which makes it more complex
• Social centripetal forces make languages, and people in the group try to conform to the language norms of the group and to show "competence" in using the language
• Humans, uniquely are able to introspect about their own behavior, to talk about talk, and to think about thinking.
• The language of a community is inevitably fuzzy at the edges, because nobody conforms 100% to the norms. But a core of normas, for any language, does exist, and individual speakers tacitly know them. 'Tacit knowledge' is an acceptable description of what is in speakers' heads, making them behave in regular conforming ways.

Instinct and Learning

• Some behavior is clearly instinctive and some is obviously learned.
• Instinctive behavior ranges from simple to relatively complex
• Emotions, such as fear and anger are themselves instinctive
• Learning is acquiring different behaviors in response to events in the environment, plasticity.
• First-language learning is reasonably called 'involuntary' (or instinctive), and adult attempts to learn new languages, 'voluntary'.
• There are involuntary drives that put one in a state ready for learning. Babies instinctively coo and babble, children have an instinct to follow eye gaze and pointing and a 'mind-reading' instinctive understanding of the goals of others (theory of mind?).
• No learning is bias-free and any bias affecting learning is itself instinctive. Children are disposed to attend selectively to objects and we have an instinctive bias to seek sense in what people say to us and a bias toward learning complex grammar.
• Humans have evolved to be the most plastic species.
• A behavior not at first automatic can be learned in a deliberate way and practised until it becomes 'second nature'. Then it is reasonable to talk of a learned instinct - something learned becomes instinctual.
• We can consciously learn to suppress or inhibit instinctive behavior as in processes of socialization.
• Social learning is based on copying the behavior of others while non-social learning is solo trial and error.
• Good solutions to practical tasks can be discovered by non-social learning, and then spread socially.
• Evolving systems need innovation, inventions of new social behaviors that others can then replicate. Such inventions need not be conscious.
• With a disposition to imitate, one can socially learn behaviors that have no obvious practical benefit. This instinct to imitate, not necessarily with any insight into meaning, is the driver for children learning language. They gain social reinforcement for playing the community's language games.

Iterated learning:

• We assume that semantically compositional language was preceded by a 'protolanguage' stage, with meaningful words but with no grammatical organization.
• While in simulations, compositional syntax emerges gradually in stages, real people have a disposition to impose order on chaos, and over successive generations, order emerges.

How Trusted Talk Started

• All animals communicate in some way, but here we're talking about behavior that influences the behavior of others, where they respond as if recognizing a communicative intention on the part of the sender of the signal.
• Animals have ritualized behavior, like the teeth-baring of dogs or birds' courtship behavior.
• Dyadic communication is when animals do stuff to each other, while triadic communication is communication about something, and triadic communication in animals shows the evolutionary seeds of reference in language.
• Whenever we talk to each other, we intend to do something to our hearer.
• What human language added to animal communication was huge potential for joint engagement of speaker and hearer with situations beyond themselves
• In the lineage of humans, and apes generally, there has been a progressive shift toward more learned behavor. Instinct never goes away completely, of course, as learning is always guided by some instinctive bases.
• Children learn ritual behavior, such as raising their arms when they want their mother to pick them up.
• In the evolution of the human capacity for language, there was a transition from purely innate instinctive communication to learned conventions over which the communicators have a high degree of voluntary control.
• Spontaneous smiles and deliberate smiles are initiated by different parts of the brain.
• Mutual communicators need to be able to maintain joint attention to whatever is being communicated about for at least as long as the communication lasts - there seems to be a co-evolutionary spiral between an increasing capacity for joint attention and increasing communicative success with language.
• In the history of languages, there is a trend for frequently made inferences to become conventionalized.
• Language signals are cheap to emit, though fairly costly to learn.
• Humans are simultaneously in cooperation and competition with other members of their social group. We walk a delicate tightrop maintaining trustful reciprocal cooperative relationships, while also making sure we are not taken advantage of and get our fair share of resources.

One for all, and all for one

• The basis of human language is a disposition to communicate cooperatively.
• Humans are conspicuously altruistic.
• Tit for tat - Help those who have helped you, and anyone you meet for the first time, and don't help a person who declined to help you in the past. It is successful because of its built-in memory of past collaborators and non-collaborators.``
• Reciprocal altruism in a group requires certain advanced cognitive traits including memory for past good and bad deeds, some way of recognizing members of your own group, and mechanisms for detecting and punishing cheaters who take the benefits of group membership without paying their dues by occasional altruism.
• As the expressive power of language evolved, so did its potential strength in forming social groups reaching beyond the bounds of close kin and humans have ruthlessly outcompeted other species with less cohesive group action.