Language and Evolution

Define language

a set of arbitrary symbols (lexicon) & rules (grammar) used to combine them for expressing thought

Hockett’s design features of language

List of 13-16 features of language that only humans have

Name some of Hockett’s design features of language

Vocal-auditory channel – Broadcast transmission & directional reception – Rapid fading – Interchangeability – Total feedback – Specialization – Semanticity – Arbitrariness – Discreteness – Displacement – Productivity – Traditional transmission – Duality of patterning – (Prevarication) – (Reflexiveness) – (Learnability)

Vocal-auditory channel

Sounds emitted from the mouth and perceived by the auditory system.

• Sign languages use the tactile-visual channel

• Primates excel in tactile-visual channels

Broadcast transmission & directional reception

Message must have an intended target, and the target can identify the broadcaster

Rapid fading (transitoriness)

Message does not linger in time or space after production

• Unlike olfactory communication or body changes

Interchangeability

Individuals with language can both send and receive any licit message within that system.

• Compare to some birds: only males sing.

Total feedback

Users of a language can perceive what they are transmitting and can make corrections if they make errors (you can hear what you say/see what you sign).

• Stickleback fish communicate through changing the color of their bellies but cannot see their own belly (Counterexample)

• But some animals (like primates) can increase their call loudness as ambient noise gets louder

Specialization

The signal produced is specialized for communication and not the side effect of other behavior.

• Compare to dogs panting — it’s communicative, but the primary function is to cool down

Semanticity/reference

There is a fixed relationship between a signal and a meaning.

• The calls of vervet monkeys demonstrate semanticity: Three distinct calls for different predators! – leopard ‘get up!’ – eagle ‘get down!’ – snake ‘look around!’

Arbitrariness

There is no direct, logical, or inherent relationship between a linguistic symbol and its meaning.

• There is nothing ‘Tuesday’ about [ˈtuzˌdeɪ]

• Primates have arbitrary “attention-getters”: (e.g., slap-ground, poke, throw-stuff)

Discreteness

Language is made of discrete units (e.g., phonemes, morphemes, words)

• cat and rat: changing [k] for [r] gives a completely different meaning; there is no gradient between.

Displacement

Linguistic messages may refer to things remote in time and space (or both) from the site of communication

Productivity

Language users can create and understand completely novel messages or words (e.g., golfoholic). We can produce an infinite number of different messages by combining the elements differently.

Cultural/traditional transmission

The conventions of a language are learned by interacting with more experienced users; it is not innate

Duality of patterning

Meaningful messages are made up of distinct smaller units (sounds) that have no meaning.

• Meaningless units: a, t, r

• Meaningful combinations: rat, art, tar

Prevarication

Linguistic messages can be false, deceptive, or meaningless.

Reflexiveness

We are aware of our own intentions to use language to communicate, and we can even communicate about communication.

Learnability

Given enough time and energy, a user of one language can learn any other language to a fairly high degree of complexity

Charles Darwin

1800s naturalist that proposed that:

– Every individual of a species is unique with differing traits.

– Competition for limited resources favors the “fittest” individuals (natural selection).

– Modern humans are most similar to African great apes

Gregor Mendel

1800s biologist who proposed that:

– Individuals inherit the traits of their ancestors.

– Monogenic, discontinuous traits are passed down predictably.

– Traits may be “dominant” or “recessive”, predictably determining their expression in various combinations.

Watson & Crick (1953)

Discovered DNA

Punnett squares

Method for predicting the genotypes and phenotypes of offspring of two parents with known genotypes

Mutation

mechanism of evolution (and therefore natural selection) in which a single base pair gene is changed.

• Leads to variation in traits

Selection

mutation (of genes) ⇒ variation (of traits) ⇒ selection (of individuals)

∘ Natural selection does not choose genes or traits, only individuals.

∘ Natural selection also depends on environmental factors and is not necessarily optimizing.

Speciation

When a new species is formed

Epigenetics

how DNA expression is controlled & regulated

Homo ergaster

Where: Africa
Tools: Mode II (Acheulian)
Other: Small brain, long limbs

Homo erectus

Where: Widely distributed
Tools: Mode II (Acheulian
Other: Small brain, shelf-brow

Homo heidelbergensis

Where: Europe, more?
Tools: Mode II (Acheulian), fire
Other: Modern brain size, unknown other size

Homo neanderthalensis

Where: Europe, Middle East, Asia
Tools: Mode III (Mouseterian), fire, clothes, boats, tar, splints
Other: Most similar to sapiens, interbreeding evidence

Homo sapiens

Where: Earth
Tools: yk
Other: Evolved in Africa, from mtDNA evidence

Put in order from oldest to youngest: Homo ergaster – Homo erectus – Homo heidelbergensis – Homo neanderthalensis – Homo sapiens

erectus, ergaster, heidelbergensis, neanderthalensis, sapiens

Name Clark’s Modes of Tools/Technology

1 Oldowan
2 Acheulian
3 Mousterian
4 Aurignacian, etc
5 Various

What does tool use tell us about the age of language?

Some have proposed that the difficulty of creating Acheulean (Mode II) tools must imply the existence of language.

• Erectus and heidelbergensis had Mode II (Acheulian) tools

Mitochondrial Eve

The name given to the XX individual which all mitochondrial DNA (no selectional pressure) originated from.

• More of a time estimate, 200 KYA

Y-Chromosome Adam

21 of 27 Y-chomosomes originated in Africa

Name the theories for human dispersal

1) Multiregional Hypothesis
2) Recent Out of Africa Hypothesis
3) Diffusion Wave Hypothesis/ Out of Africa Over and Over

Multiregional Hypothesis

Homo sapiens evolved as a continuous species globally from other hominin populations.

Recent Out of Africa Hypothesis

Homo sapiens migrated out of Africa and replaced the other hominin populations.

• Weak vs strong

Diffusion Wave Hypothesis/ Out of Africa Over and Over

A modification of ROAH where Homo sapiens traits spread through hominin populations.

What is the difference between a ritualized display and a signal (w/ examples)?

A ritualized display has become innate, unconscious.
Examples: dog bearing teeth, primate initiate play movements

Hyoid development

Tongue bone which anchors the tongue and opens pharynx and larynx

• “physical machinery”

• erectus and neanderthalensis

Cranium size

Generally, cranial size has increased as hominins have developed

• “mental machinery”

• doesn’t take into account body size, encephilization quotient would

Jaw bones

Blasi et al. (2019) has claimed that the advent of agriculture and grain diets has allowed the production of “labiodental” consonants [f, v].

• Issues: introduces connections between diet & language, assumes that modern distribution implies change

Larynx height

Fire

Provides advantages (light, heath, food & material processing) that allow more calories to be devoted to language processing and development

What are three theories of language development?

– The Tower of Babel/Babylonian confusion

– Goropism

– Gestures-first theory

The Tower of Babel/Babylonian confusion

Referenced in Genesis in the bible, references when all humans spoke one language (Adamic)

Gestures-first theory

Goropism

Hypothesis that one language is the ancestor of all others

Uniformitarian Hypothesis

Introduced by Lyell’s Principles of Geology, it was the notion that the same natural laws apply in the past and present

Neogrammarian Hypothesis

Sound change is regular (effects ALL targets in a given environment) and phonetically conditioned

Grimm’s Law

PIE*t changed to PGmc *p
BUT there were exceptions

Verner’s Law

Development is conditioned / Exceptions to Grimm’s Law are because sound change is dependent on where accent / emphasis is

Dichotic listening

Experiments that showed that information from the R ear is reported more often than information from the L ear

• because ears are connected to the brain hemispheres ipsilaterally, this means the L hemisphere is more central to language processing

• opposite for music

Split-brain patients

When the corpus callosum is severed, the hemispheres cannot communicate, resulting in infor from R eye being able to be articulated (because processed in L hemisphere), but not vice versa

Wada tests

When the L brain hemisphere is put to sleep, the subject is unable to produce language

Ultrasounds

Broca’s aphasia

OK word selection / semantics
POOR combination of words (especially connecting, closed-class, function words) / syntax

Wernicke’s aphasia

POOR word selection / semantics
OK combination of words / syntax

Specific Language Impairement (SLI)

Similar to Broca’s aphasia, this is a disability in children in which they omit “function” words (of, the, is)

• children normally fall in typical IQ range

William’s syndrome

• limited spatial and motor skills

• High vocab and grammar, “off” semantics

FOXP_2

Double dissociation

Demonstration that two mental faculties are independent from one another

• Broca’s and Wenicke’s aphasias show that syntax and semantics are handled separately

• SPI and William’s syndrome show that language and intelligence are not identical