Difficulty: Introductory to Intermediate | Prerequisites: PSY 3215 introductory lectures on infant cognition and early social development.
This topic sits at the intersection of developmental psychology and psycholinguistics. It covers how infants and young children acquire language, how they communicate before and during early word use, and how the social context (parents, peers, situational factors) shapes that development. You should already be comfortable with basic developmental milestones in infancy. If terms like "prenatal" and "postnatal" or concepts like motor development timelines are unfamiliar, revisit your Chapter 1 and 2 notes first.
Language development in infancy involves far more than first words. Children communicate through joint attention, conventional actions and intersubjectivity well before they speak. Key properties of language (displacement, productivity, semanticity) explain why human communication is uniquely powerful, and contextual factors, from caregiver responsiveness to peer familiarity, shape how and when these abilities emerge.
Conventional actions
Actions that represent another action or an object using a ritualised manner of expression, such as waving or saying "bye-bye."
In simple terms, these are the gestures and routines babies learn by imitating adults, like clapping or waving goodbye.
Displacement
The property of language that allows speakers to express concrete and abstract ideas and describe objects not physically present.
Think of it as the ability to talk about things that are not right in front of you, like yesterday's breakfast or a faraway country.
Intersubjectivity
Acting cooperatively and deliberately involving others as meaningful agents in one's actions.
In simple terms, this is the moment a baby treats you as a partner in what they are doing, not just background scenery.
Joint attention
When communicating partners direct their attention to the same object or topic.
Think of it as a baby and a parent both looking at the same toy and knowing they are both focused on it.
Metacommunicative events
Communicative acts that refer to the relationship between partners rather than to the world outside the relationship.
In simple terms, communication about the communication itself, or about the bond between people (e.g., a smile that says "we're playing together").
Overextension
Applying a single word to refer to more objects and situations than it normally refers to in adult speech.
Think of it as a toddler calling every four-legged animal "doggy."
Pragmatics
The study of the functional uses of language, as opposed to its structural (grammatical) properties.
In simple terms, pragmatics asks "what are you doing with your words?" rather than "is your grammar correct?"
Productivity
The ability of language to express multiple meanings using a small number of words simply by rearranging word order in novel ways.
Think of it as the reason "dog bites man" and "man bites dog" mean completely different things with the same three words.
Semanticity
The ability of language to carry meaning for both speaker and listener.
In simple terms, words have shared meaning: when you say "apple," other people picture roughly the same thing you do.
Situational constraints
Elements of the context of a stimulus or event that determine a child's response to that event. Examples include a peer's age, sex, and familiarity to the infant, the infant's prior experience with other children, and the caregiver's location.
Think of it as all the background variables (who's there, where the parent is sitting, how familiar the other child is) that shape how a baby behaves in a social situation.
Infants with special needs
Infants who suffer from prenatal and postnatal deficits, deformities, and developmental delays that create additional challenges for them and their families.
In simple terms, babies whose development is complicated by medical or developmental conditions present from before or just after birth.
Human language is set apart from other communication systems by several core properties:
Semanticity: words carry shared meaning between speaker and listener.
Productivity: a finite set of words can be rearranged to produce an infinite number of meanings.
Displacement: speakers can refer to things not physically present, including past events, future plans, and abstract concepts.
These three properties together explain why language is so much more powerful than, say, an animal alarm call.
Conventional actions (waving, saying "bye-bye") appear before true words. They show that infants understand symbolic representation.
Joint attention emerges when a baby and caregiver focus on the same object and are aware of the shared focus. It is considered a foundation for later language learning.
Intersubjectivity goes a step further: the child treats others as intentional partners, not just objects in the environment.
Metacommunicative events are moments where the communication is about the relationship itself ("we are playing together") rather than about external objects or events.
When children begin using words, they often overextend them. A child might call all round objects "ball" or all men "daddy." This reflects the child's attempt to use a limited vocabulary to cover a wide range of referents. It is not a sign of confusion; it is a rational strategy given limited word knowledge.
Children across cultures begin talking about emotions and thoughts at roughly the same age, but the sophistication of their language shows a clear developmental sequence:
Early stage: labelling one's own emotion ("I sad").
Middle stage: labelling someone else's emotion ("Karen scared," "Daddy happy").
Later stage: expressing cognitive states and mental verbs ("I know!").
A child who says "I know" is demonstrating awareness of their own mental state, which is more developmentally advanced than simply labelling an observable emotion.
Research shows that fathers are just as responsive to infants as mothers. They use similar amounts of stimulation and are equally effective as caregivers. This finding challenges older assumptions that mothers are inherently more attuned to infant needs.
Most children develop a hand preference by age 3, though some do not settle on a dominant hand until age 5. This is a normal range of variation, not a cause for concern.
How an infant responds in a social situation depends on context. Relevant factors include:
The peer's age, sex, and familiarity.
The infant's own prior experience with other children.
The caregiver's physical location during the interaction.
These situational constraints can either support or hinder the quality of infant peer interactions.
Students often think overextension means a child is confused about word meanings. It does not. Overextension is a perfectly rational strategy for a child working with a limited vocabulary.
Students sometimes assume that fathers are less responsive to infants than mothers. Research does not support this: fathers are equally responsive and effective.
Students often believe that if a child has not developed a hand preference by age 3, something is wrong. In fact, some children do not settle on a dominant hand until age 5, and this is within normal range.
Students may confuse pragmatics with grammar. Pragmatics is about the functional use of language (what you are doing with your words), while grammar is about structural rules.
The distinction between semanticity, productivity, and displacement is a common exam target. Know each property and be able to give an example.
The developmental sequence of emotional language (labelling own emotion, then others' emotions, then mental states like "I know") is frequently tested as a multiple-choice ordering question.
Joint attention vs. intersubjectivity: know the difference. Joint attention is shared focus on an object; intersubjectivity is treating the other person as an intentional partner.
Father responsiveness is a reliable true/false item. The answer is always: fathers are just as responsive and effective as mothers.
Overextension is a favourite definition question. Be able to define it and give an example.
True or False: Displacement refers to a child applying a word too broadly. (False. That is overextension. Displacement is the ability to talk about things not physically present.)
True or False: Fathers are just as responsive to infants as mothers. (True.)
Fill in the blank: When a baby and caregiver both look at the same toy and are aware of the shared focus, this is called ________. (Joint attention.)
True or False: Most children develop a hand preference by age 3, but some do not until age 5. (True.)
Fill in the blank: The study of the functional uses of language, rather than its grammatical structure, is called ________. (Pragmatics.)
Q: Which property of language allows a speaker to describe an object that is not physically present?
A: Displacement.
Q: A toddler calls every man "daddy." What term describes this behaviour?
A: Overextension.
Q: Across cultures, children talk about emotions and thoughts at roughly the same time but show a developmental sequence. Which of the following children is likely the oldest: one who says "I sad," one who says "Karen scared," one who says "Daddy happy," or one who says "I know"?
A: The child who says "I know," because expressing a cognitive or mental state ("knowing") is more developmentally advanced than labelling observable emotions.
Q: What is the difference between joint attention and intersubjectivity?
A: Joint attention is when two communicating partners direct their attention to the same object or topic. Intersubjectivity goes further: it involves acting cooperatively and treating others as intentional agents in one's own actions.
Q: Name three situational constraints that can affect the quality of peer interaction between infants.
A: The peer's age, sex, and familiarity to the infant; the infant's own prior experience interacting with other children; and the caregiver's physical location during the interaction.
Q: True or False: Fathers use less stimulation with infants than mothers do.
A: False. Fathers use similar amounts of stimulation and are just as effective.
This material connects directly to cognitive development (Piaget's sensorimotor stage), where early symbolic thinking underpins conventional actions and language use. It also ties into attachment theory: the quality of caregiver responsiveness (including father involvement) shapes the social context in which language develops. If you cover theory of mind later in the course, the developmental progression from labelling emotions to expressing mental states ("I know") is an early precursor to understanding that other people have different beliefs and knowledge.
Language development, infant communication, PSY 3215, developmental psychology, joint attention, intersubjectivity, overextension, displacement, productivity, semanticity, pragmatics, metacommunicative events, conventional actions, situational constraints, peer interaction, father responsiveness, hand preference, hand dominance, laterality, emotional language development, cognitive states in children, theory of mind precursors, pre-linguistic communication, infant special needs, Florida International University, Psychology II