One word for green and blue: do its speakers see colour differently?

Which comes first, thought or language?

• Piaget: language depends on thought. Thinking develops first; language comes later to express it.
• Representational thinking: before they can talk, babies form mental pictures of objects, e.g. searching for a hidden toy.
• Children who could not yet conserve were taught words like "longer" and "fatter". The words alone did not help them conserve: the concept must come first.
• Weakness: babies can't tell us their thoughts, so it's hard to test.

Vygotsky: two separate paths

• Vygotsky said language and thought start separately, then join.
• Pre-linguistic thought: thinking without words, e.g. a baby working out how to reach a toy.
• Pre-intellectual language: sounds and words without thought behind them, e.g. babbling, crying, copying a word.
• Around age 2–3 they join: thought becomes verbal and speech rational. Later, self-talk becomes silent inner speech.
• Strength: children talk themselves through hard tasks. Weakness: harder to test than Piaget.

Can your language shape your thinking?

• The Sapir-Whorf hypothesis: thinking depends on language. It comes in two strengths.
• Linguistic determinism (strong version): language limits thought. With no word for something, you can't think about it.
• Linguistic relativism (weak version): language influences thought. Words make some things easier to notice, sort and remember.
• So two people whose languages divide the world differently may see it a little differently.

Evidence from colour and memory

A bee dances and the hive finds new flowers. Is that language?

Why animals communicate

• Animal communication is passing information between animals of the same species.
• It serves a small set of functions:

How the bee dance works

• A bee that finds food dances on the comb in the hive. Others follow it, then fly to the food.
• Round dance: circling, when food is near.
• Waggle dance: a figure of eight with a straight "waggle run", when food is further away.
• Direction: the waggle run's angle from straight up matches the angle between the food and the sun.
• Distance: the longer the waggle run, the further the food.

What human language can do

• Humans communicate about anything, not only survival, mating, territory and food.
• Displacement: talking about things not present, in the past or the future. You can plan ahead and discuss next week's party.
• Creativity (productivity): making endless new sentences nobody has said before.
• Animal signals are a fixed set about the here and now. A bee can't tell the hive about yesterday's flowers.

Aitchison's criteria of language

• Aitchison (1983) set out ten criteria that a full language meets. Animals show some of them, e.g. turn-taking, or a vocal-auditory channel in birdsong.
• Four key ones, which only human language shows fully:
• Semanticity: words and symbols carry shared meanings.
• Displacement: talking about things not here and now.
• Structure dependence: grammar; word order changes meaning ("dog bites man").
• Creativity: making endless new messages.

Stand too close to a stranger and they step back. Who set the gap?

Saying it without words

• Verbal communication uses words, spoken or written.
• Non-verbal communication (NVC) sends messages without words.
• Main types: facial expressions, eye contact, body language (posture, gestures, touch) and personal space.
• NVC often says more about feelings than words do, e.g. a "fine" said with a frown.
• Facial expressions show emotions such as happiness, sadness, anger and fear.

What eye contact does

• Regulating the flow of conversation: speakers look away as they start talking, then look back at the listener as they finish, signalling "your turn".
• Signalling attraction: we look more at people we like, and our pupils widen.
• Expressing emotion: a long stare can show anger; avoiding eye contact can show embarrassment or sadness.

Body language

• Open posture: arms and legs uncrossed, relaxed; signals friendliness and acceptance.
• Closed posture: arms folded or legs crossed; can signal disagreement or defensiveness.
• Gestures: hand and arm movements such as a wave or thumbs up. Their meaning varies between cultures: a gesture that is friendly in one country can be rude in another.

Personal space

• Personal space is the area around you that feels like yours; uninvited entry feels uncomfortable.
• Proxemics is the study of how people use space.
• Hall's approximate zones: intimate (up to 45 cm), personal (45 cm to 1.2 m), social (1.2 m to about 3.6 m) and public (beyond that).
• Culture: comfortable distances differ. In many Latin American cultures, friends stand closer than is usual in the UK or Northern Europe.

Babies born blind smile. Why do cultures read one face differently?

Darwin: expressions evolved

• Darwin (1872) said facial expressions and other non-verbal signals evolved because they were adaptive: they helped our ancestors survive and reproduce.
• Genes for useful signals were passed on, so the signals became innate (inborn) and universal.
• Example: baring the teeth began as getting ready to bite. It became a signal of anger that can warn off an attacker without a fight.
• A baby's smile and cry win carers' attention.

Evidence that NVC is innate

• Neonates (newborn babies) smile, cry and pull a disgust face within days of birth, before they could have learned them.
• Sensory deprived: children born blind smile, frown and cry like sighted children, though they have never seen a face.
• Athletes blind from birth made the same expressions as sighted athletes when they won or lost.
• Some expressions (e.g. happiness, sadness, anger, fear, disgust, surprise) are recognised across many cultures.

Evidence that NVC is learned

• Gestures differ between cultures. A thumbs up or "OK" sign can be friendly in one country and rude in another.
• Cultures have display rules: learned rules about when to show or hide feelings, e.g. hiding disappointment in front of a teacher.
• How people interpret faces also varies with culture. If it were all innate, everyone would read faces the same way.

Big ideas

• Piaget: thought comes first and language expresses it. Vygotsky: they develop separately (pre-linguistic thought, pre-intellectual language) and join around age 2–3.
• Linguistic determinism (language limits thought) is not supported; linguistic relativism (language influences what we notice and remember) has support from colour studies and Boroditsky's study of time.
• Key question: how do you communicate with others? Partly through words that shape how you think.
• Animal communication serves a few functions: survival, reproduction, territory and food. The bee dance carries direction and distance, but only about food.
• Human language has properties animal communication lacks, such as displacement (planning ahead, discussing the future) and creativity, which are among Aitchison's (1983) criteria with semanticity and structure dependence.
• Key question: how do you communicate with others? With a language that can talk about anything, anywhere, any time.
• Verbal communication uses words; non-verbal communication sends messages without them, through facial expressions, eye contact, body language (postures and gestures) and personal space.
• Eye contact regulates conversation, signals attraction and expresses emotion; open and closed postures signal different attitudes.
• Personal space (proxemics) varies with culture.
• Darwin: non-verbal signals evolved because they were adaptive, so many are innate and universal.
• Newborns and people born blind show basic expressions without learning them; but gestures, display rules and how faces are read are learned in a culture (Yuki et al., 2007).
• Key question: how do you communicate with others? With signals that are partly inborn and partly learned from your culture.