Perceptual Development PDF

SECTION II Perceptual development ❖ Methods for studying infants What they can do Display physiological responses Look Preferential looking: children tend to look more at face-resembling images than random one...

SECTION II Perceptual development ❖ Methods for studying infants What they can do Display physiological responses Look Preferential looking: children tend to look more at face-resembling images than random ones Head turn preference: listen to sound from speakers, know if they orient themselves towards it then they choose which one they prefer to orient themselves towards more often Habituation: present same stimulus until infant stops looking Violation of expectation Suck High amplitude sucking: two different speakers and examine difference in amplitude of sucking when comparing sounds What perceptual abilities are innate? What’s the role of experience? Basic story Prenatal development Postnatal tuning (tuned in for the things the organisms need to do) Some perceptual abilities, preference presence at birth Some are biologically based, specified Some due to prenatal learning Development involves changes in body, brain, and behavior Perceptual narrowing in early development Newborn sensory capabilities Vision is least well-developed sense ◆ Sensitive to brightness; can discriminate patterns, some colors; track motion ◆ Acuity poor, improves rapidly in first ½ year  Hearing relatively well-developed ◆ Turn to sounds, can discriminate loudness, direction, frequency ◆ Responsive to speech, phonemic contrasts ❖ Development of visual perception Changes in body – in the eye Changes in brain Changes in behavior: how to look at faces and what to look at Movement is critical! Visual scanning patterns Motor development, including locomotion Different types of cues Monocular Binocular Motion-based ❖ Depth perception: some forms present at birth, other later Monocular (1 eye) cues to depth: motion-based cues early, pictorial cues later Binocular (2 eyes) cues to depth: 4mos ❖ Tuning of visual perception Becomes more selective over first year, as a function of experience Face perception: experiences with faces of different species, races, ages  Perceptual narrowing with experience: 6 mo can discriminate novel monkey faces, 9 mo cannot Infants habituated to target face Then presented with novel & familiar faces Recognition: looking preference for novel face over two 5s intervals 4 racial groups Results: White 3mo showed a preference for the novel face for all 4 racial groups White 9-mos showed preference for the novel face only for white faces Perceptual narrowing: experience is needed to maintain perceptual discrimination abilities ❖ Auditory perception development Relatively well developed at birth Auditory learning in fetuses: at birth Preference for… Mom’s voice Native language Familiar story Familiar music Auditory localization: present at birth (knowing where a sound is coming from U shaped developmental trajectory (birth-5mo) Subcortical vs cortical processing Control of head movements, strength of neck Changes in head size Paper - dis/cont - Mechanisms of change - Valuing motor skills (look at slides) - Textbook: in chapter ___ - Lectures: in lecture ___ - Cite readings Perceptual and language development ❖ Categorical perception Tuning of auditory perception for speech  Tuning of auditory perception All in all, we agree when to separate sounds to categorize them High amplitude sucking paradigm: dishabituated → also agree when it’s a different letter Social context: infant directed speech (IDS) Higher pitch, wider range of pitch, exaggerated intonation, etc. Infants prefer IDS over Adult Directed Speech Could it help infants learn to perceive speech Exaggerates difference between vowels → better speech perception Tuning of auditory perception: categorical perception of speech sounds Social context may play a role (IDS) Narrows with experience Early on, infants sensitive to many distinctions not used in the languages they hear With time, infants lose ability to distinguish contrasts not used in their languages Music Discrimination of sounds of different pitches Measure: detect mis-tunings in scale Infants trains with operant conditioning paradigm Visual reinforcer appeared above speaker when there was a mis-tuned note Measured head turns Adults raised hand to indicate mis-tuned notes Results: ability to detect mis-tuning narrows with experience ❖ Intersensory integration: integration of information from 2+ sensory systems  Opposing views: integrated from start vs initially separate, gradually integrated Basic story Simple forms present at birth ❖ Visual-tactile integration 1-mos suck for 90 sec Preferential looking test: orange styrofoam shapes 72% of fixation time to matching shape ❖ Intersensory redundancy hypothesis (bahrick & lickliter) Infants’ attention attracted to information that is redundant across senses, synchronous Attentional focus leads to better learning of amodal properties from multimodal stimuli Ex: rhythm Better learning with audio-visual input ❖ Redundancy matters Attention drawn to multi-modal information Temporal synchrony matters Consider Faces and voices Speech & gestures Action & sound ❖ Perception and action Perception guides action Exploratory movements (actions) generate perceptual information Motor skill development has consequences for perceptual development Visual cliff Why are crawlers afraid of cliff? Key is self-produced locomotion Self-produced locomotion generates synchronous, multi-modal experience (vision + proprioception) ◆ Intersensory redundancy hypothesis Action allows for perceptual experience How do infants learn to perceive the backs of objects?  Sitting experience associated with looking preference ◆ Infants with different motor abilities made different inferences about the backs of objects → more interested in novel display (display C) Sitters manipulate objects while looking at them Manipulating-while-looking associated with looking preference Sticky mittens study Motors skills allow interactions with objects (couldn’t do it otherwise because no ability to grab things yet) ◆ Cascading consequence ❖ Main points Narrowing of perceptual abilities with experience (shaped by social, cultural, linguistic context) Redundant, synchronous information attracts attention, promotes learning Exploratory movements generate perceptual information Motor skill development has important consequences for perceptual development ❖ Language development Phonology The sound you make to say the word Meaning Morphology Semantics lexicon Grammar syntax Communication Pragmatics Gestures Lecture 12 Language development ❖ Phonology: producing sounds ❖ Meaning: learning words ❖ Grammar: putting words together ❖ Nurture: empiricist views Children reinforced for linguistic behaviors (Skinner) Social learning, imitation HOWEVER, evidence for strict empiricist views is weak Large variations in experience lead to highly similar outcomes  Language is generative ❖ Nature: nativist views (chomsky) Universal grammar Exposure sets “parameters” Language acquisition device Poverty of stimulus argument Specialized perceptual and cognitive abilities ❖ Nativist views: evidence Linguistic universals: true of all languages Brain specialization for language Broca’s area and wernicke’s area Home sign systems Critical or sensitive period for language acquisition Period during an organism’s life when it is more sensitive to environmental influence or stimulation than other times ❖ Sensitive period hypothesis Language acquired most easily before puberty Evidence: Childhood aphasia Case studies of linguistic deprivation ◆ E.g. genie Isolated from 20 mos to 13 ys, 7 mos Acquired some, but not all aspects of language Second language learning Late learners of sign language as 1ST LANGUAGE ◆ Not as good as native or early learners Children who learn sign from late learners ◆ Parents not as well as adult native signers ❖ Interactionist perspective  Interplay of biological and environmental factors Linguistic universals derive from common experiences Language used in social context Child-directed speech Adult responses to child errors Scaffolding ❖ Nature AND nurture Biological preparedness for learning Learning happens in rich social context ❖ Sequence of language acquisition Newborn: prefers speech, discriminates phonemas, cries 1-4mo: sensitive to prosodic features of speech 4-6 mo: babbles 9-12 mo: reduplicated babbling, first gestures 12-18mo: one-word utterances 18-24 mo: vocab growth (spurt) About 2yrs: two-word utterances Preschool years (2.5-5): increasingly complex utterances, humor & metaphor, vocab & communication skills grow ❖ How nature & nurture come together in… perceiving, producing sounds identifying larger units linking sound and meaning putting units together Coos: vowels more like Babbling: has consonants and vowels ❖ Babbling Combining consonants and vowels (CV) Assumed to be motor practice May be functionally important for language development ❖ Active child - responsive environment Different vocalizations, different maternal responses Infants produce more developmentally advanced vocalizations → mothers provide more advanced responses Baby more language-like → caregiver more interactive Vowel-like vocalizations Play responses: sound effects “vroom vroom” Consonant-vowel vocalization Imitations and expansions “Yes dada is at work”  Interactions Eye contact/visual contact Caregivers are responsive to babble 8 mo infants Moms responded with interactive vocalizations when infants produced more advanced sounds Social interaction shapes babble Contingent condition: moms asked to respond to babble by smiling, touching, moving closer Yoked control: moms instructed to respond in same way–not contingent on baby’s babble Same timing and vocal form 2 types of input: Resonant vowels Consonant-vowel alternation Results: Babies matched moms – increased the kinds of sounds moms made Social contingency matters – increases with contingent interaction, but not in control condition ❖ Segmenting speech: into units and then giving meaning to those units to give sound meaning How do we know where breaks are Pauses (between words) Prosody (changes in pitch) Correlations (statistical regularities) ❖ Statistical learning: segmenting helps babies learn the meaning of words Statistical learning experience Habituated to label-object pairing Switch object label pairing Looking time only increases for “words” ❖ Meaning Quine’s problem: how can we figure out what words mean? Some answers: Biases or constraints Grammatical cues Statistical cues Social context ❖ Constraints on learning Biases about what words might mean Mutual exclusivity constraint  Ex: show me the gug ◆ “Not the spoon” → assume the other is the “gug” Whole object constraint Shape bias Whole object assumption: what makes something a particular kind of object? Material Color Shape ❖ Where constraints come from Biologically based? Not specific to language Learned from experience? At least the specifics Samuelson & smith connectionist model about the shape bias ❖ Statistical cues: cross situational word learning How frequently you hear the same word for the same item ❖ Grammatical cues Ex: the duck is “gorping” the bunny (to the other) The duck and the bunny are “gorping” (both are doing this) Syntactic bootstrapping ❖ Social context Parents scaffold word learning Direct kids’ attention Point Vocal emphasis Use routines Follow kids’ attention Joint attention ❖ Successful learning and attention  → attention directed to object will help learning AND timing matters (right as object is presented) ❖ Explicit teaching 4yo: mom, mud is when it rains on the dirt and it gets ick, and dirt is when it’s dry right? 11yo: is this a parody of __ song? ❖ Word learning Inductive problem Multiple answers “Biases” or constraints Grammatical cues Statistical cues Social context ❖ Words do not = language Early on: single words represent complex meanings “Holophrastic” period Vocab growth initially slow, then speeds up (18-24mo) “Naming explosion” or vocab spurt Over- and under- extensions common ❖ Combining ideas Later: combining ideas Word + gestures Word + word Two-word combinations: approx 2yrs Simple sentences, mainly nouns & verbs Few modifiers, connectors, etc. Basic semantic relations ❖ Parents’ role in grammar learning Modeling correct performance  Expansions Child: juice Mom: would you like some more juice? Error correction Infrequent for grammatical errors (more for factual errors) Not so effective! Overregularization Child: I used to wear diapers. When I growed up… Father: when you grew up Child: when I grewed up, I wore underpants Ex: wug vs wugS ❖ Communication Turn-taking, politeness conventions Indirect requests It’s hot in here “Repair” when communication goes away Taking listener knowledge into account ❖ Referential communication 3yrs fail 4yos succeed w/familiar but not novel shapes (ex: triangle) Try to put blocks in same order as partner ❖ Nature and nurture in language development Biological preparedness for learning Learning by taking in info from the environment Statistical patterns Learning happens in rich social context Learning continuous throughout childhood ❖ Basic processes in memory Encoding Storage Retrieval  (rehearsal) ❖ Memory systems Time Sensory vs short term vs long term Types Declarative vs procedural Explicit vs implicit Explicit: recall, reportable Implicit: recognition, non-reportable Evidence for implicit memory ◆ Physiological ◆ Recognition of degraded stimuli ◆ Reaction times (priming) ◆ Looking time looked at side with more changes Semantic vs episodic ❖ Encoding and implicit memory 5yos vs adults Study phase, recognition tests 3 conditions Baseline (study picture Induction (does it have beta cells? Only cats) Blocked categorization (is it young or mature) Tested with old items and lures Coded “hits” and “false alarms” Adults remembered less and less than the kids in the induction condition  People just needed to get the category, kids looked at details of individual cats as well ❖ Explicit memory Gets better as kids get older Testing in kids that can’t talk Gong test Hit gong, waited a while later, older kids remembered how to use gong for longer time ❖ Memory strategies demo ❖ Infantile childhood amnesia Inability to remember things before 2 or 3 Neurological development As brain changes, memories can be lost through pruning Incompatibilities between young children’s encoding and older children’s/adults’ retrieval Differences in knowledge structures Memories encoded nonverbally, retrieved verbally Caregivers’ social scaffolding of memories increases as toddlers grow ◆ elicit/tell stories about past ◆ Elaborate, provide detail Poor memory for things in early childhood (10yrs) More traumatic for our class ❖ Accounts of memory development Neurological Information processing Strategies Metacognition Content knowledge Sociocultural Language as a tool Learned strategies Memory discussions ❖ Social scaffolding of memory  Parent leads child to correct memory Superbowl bumping head incident ❖ Caregiver style High elaborative Provide rich information about past events Often confirm, extend children’s contributions Low elaborative Little narrative structure Few details about content Rarely expand on children’s contributions Elaborative style matters Children of HE mothers report more about past events than children of LE mother At the time when parental style is assessed Later in development Elaborative style affects encoding AND retrieval Staged “camping” activity Varied style during event (encoding) and at post-event interview (retrieval) ❖ What do caregivers emphasize in memory discussions Individual focus Creating a unique “personal story” Interrelated focus Adhering to social norms, expectations for behavior Cultural differences: US focus more on individual, chinese focus more on interrelatedness Variation in views of self Autonomous self goals - emphasize individuality Bicultural memory (wang, shao, li) → language matters Ethnic chinese children in Hong Kong, proficient speakers of english and chinese Randomly assigned to english or chinese interview 4 past events, self-description Endorsement of chinese cultural values ◆ Interpersonal harmony, group solidarity, social compliance, humility Western independent values ◆ Autonomy, personal sufficiency, pride  Child witnesses Social interactions about events matter Challenges specific to child witnesses, research Typically uncommon, negative events No record of events Unethical to manipulate occurrence of events eyewitness testimony False memory Fabricated (entirely untrue) Distortions (partially true, mixing up details) implanted/misinformation (provided by others) NOT lying Omission Commission: misattribution, distortion How to study suggestibility Stage event, vary prior discussion, questioning “Sam stone” studies (leichtman & ceci) ◆ Tell kids that sam is clumsy guy Stereotypes and suggestions matter Track real event, vary post-event feedback “I hardly cried when I got my shot” How to help eyewitness testimony NICHD protocol Interview children asap Use neutral and open-minded questions Avoid misleading info, language Recall may be inaccurate even if not intentionally lying Ex: car “smashed” vs “hit” vs “bumped” vs “contacted” Lecture 15: concepts ❖ Development of Concepts Concepts and categories Theories of concept structure Mathematical concepts ❖ Concepts and categories Concept: Knowledge or representation used to group similar objects, events, ideas, or people Category: set of entities that are grouped together Why is categorization important? Simplifies the world Reduces memory load Helps store/retrieve information efficiently Helps generalization Reduces need to relearn Supports inferences ❖ Theories of concept structure Defining features Set of criteria define the category All members of category meet all criteria Advantages Intuitive appeal Simplicity Defining vs characteristic features Importance of features changes with age Could this be an island example Defining feature: cold place surrounded by water Characteristics: people with flowers in their hair, palm trees, etc. As you grow older (kindergarten to 4th grade) lean more towards defining features Defining features limitations Need to learn the defining features/rules for each concept Hard to define necessary and sufficient features “Typicality” effects Probabilistic features Concepts represented in terms of likely features Learned through experience, honey by example Ex: flying for birds or having a beak it is likely a bird Key ideas  Cue validity: frequency with which the feature accompanies that concept and on the infrequency with which the feature accompanies other concepts Correlations among features Prototypes: most representative instances of a concept ◆ High feature overlap with other instances of same concept ◆ Low feature overlap with instances of different concepts ◆ Based on experience ◆ Prototype learning (posner & keele) Category training in adults (through feedback) Learned to classify 16 patterns into 3 categories See dot patterns, judge whether each belongs to category A or B, guess at first and get better with feedback Results: participants and infants abstracted the prototype (looked familiar enough to say that it was not new) Limitations to probabilistic features To learn probabilities, need to attend to relevant features for each instance But what’s relevant Ad hoc categories ◆ Ex: what’s the relevant feature that makes things such as backpack items go together in the same category (don’t look similar Theory-based representations: instances of concept cohere because of underlying relations among features Causal connections Background knowledge Best account for ad hoc categories Ex: whale and mouse being a mammal because it gives birth and no eggs Also true of “natural” categories Example: 2 groups given identical descriptions of “wugs” and “gillies” Experiment group told why wugs and gillies had properties Results: Exp > control at categorizing new examples, remembering categories Theory-base representations limitations Causal relations not obvious, often not directly observable Correlated features does NOT equal causal relations What counts as a “theory?” ❖ Different domains… Theory-based representations may be best for Biology Psychology Sociology Defining-features representations best for Physics Mathematics The “best” # for even numbers is 400. Other #s are still even #s ❖ Key mathematical concepts Number Exact vs approximate Natural, integers rational Operations Approximate number system Ratio dependent (weber fraction) 6mos can distinguish 1:2 10mos: 2:3 5yos, 4:5 With age and experience, make finer distinctions Also animals: non-human primates, rates, chickens System has remained similar throughout evolution Preschool ANS predicts math scores at 6 Exact number with small sets Subitizing Range generally up to 4 Lower for younger children Subserved by “object file system,” which allows tracking a small number of items Counting principles One-one: each dot gets a number, no continuing after Stable order: in order, don’t skip or mix up where numbers are Abstraction: counting different items (don’t have to look the same) Order-irrelevance: if there are 7, don’t start at 6, start at 1 Cardinality: last number tag tells us how much there actually is Principles first or procedures first? Kids have principles but can’t implement them? Kids learn principles from doing? Cultural tool: the counting system Lecture 16 (concepts pt 2) ❖ Number system Whole numbers Zero Negative numbers Rational number: fractions, decimals, percentages ❖ Relevant factors Experience Cultural tools Instruction ❖ Understanding fractions 4 > 5? ¼>⅕? How many #’s between 2 and 3? Between ½ and ⅓? When you multiply two numbers, the result is bigger than either number: T or F ❖ Operations Effects of operations hinge on number type At first: small whole #’s Some evidence in early infancy ❖ Infant addition and subtraction ❖ Foundational theories Naive physics: objects and how they interact Naive psychology: people and how they interact Naive biology: living things and how they change ❖ Theoretical frameworks  ❖ Differing views Early bio reasoning not distinct from psychology Truly biological theory only around 6-8yrs Develops from theory of psychology via conceptual change Early bio reasoning is already theoretical Base on cognitive biases, child is the theory builder ❖ Theory-theory Fundamental categories unique to the domain Causal explanations unique to the domain Unobservable explanatory constructs Coherent organization ❖ Biological concepts Key concepts life/living things Reproductions Illness Death Misconceptions are common ❖ “Naive” biology Fundamental categories Living things, animals, plants, etc. Causal explanations Growth, again, death Unobservable explanatory constructs Genes, DNA, germs ❖ Early ability to discriminate animate vs inanimate What features matter? Eyes, faces, goal-directed behavior, biological motion Biological motion Preference for biological motion at 2 days  Baby more interested in point light displays that resemble joints of humans than a ball What is alive? Piaget’s “stages” for what is alive Activity Movement Spontaneous movement Animals and plants ❖ Essentialism & biological thinking: belief that some internal property or “essence” determines the characteristics of the entity Ex: essence of “tiger” leads to sharp teeth, clase, etc. Key feature of bio reasoning Understanding of species Organisms can’t change (very much) Species can’t change (might also underlie stereotypes) ❖ Acceptance of biological change (in the essence perspective) Growth Size Weight Color Metamorphosis Knowledge matters: if you have more experience with certain animals, you are more readily accepting of biological change (ex: seeing caterpillars change to butterflies) ❖ Does culture influence essentialist views? Basic idea: underlying biological “essence” that makes a biological entity a certain “kind” of thing What is essence? Varies with cultures Biological elements: DNA, Blood, Heart? Spiritual elements: soul? Cow vs pig example Those who were native american thought with blood transfusion, cow becomes more like the pig ❖ How does biological knowledge develope? Initial model Arises form cognitive constraints/biases; observation of regularities Synthetic model Initial concepts + info acquired from culture  Scientific model Acquired via formal education ❖ Understanding of death Important from clinical perspective Piaget’s view of death: understanding limited in early childhood Difficulty understanding abstract concept of death Difficulty distinguishing alive/nonliving/dead Children more competent than piaget thought Understand death at an earlier age Understand death in plants before animals, people Understand death in terms of sub-concepts Subconcepts of death Universality: all living things die Irreversibility, finality: death cannot be reversed Non-functionality: body no longer functions after death (cessation of functions) Causality: can be many different causes By 5: death as irreversible, involves cessation of functions Death as inevitable, but not good understanding of causes Death rarely viewed as “purely biological” phenomena Often viewed in religious/spiritual terms Death rarely encountered in the “abstract” Often surrounded by strong emotions Death viewed quite differently in different cultures Ex: día de los muertos is celebrating the dead 82% of children believed dead relatives came back to visit during DDM 79% believed dead relatives ate the food at the ofrenda 56% claimed they saw, smelled, or interacted with dead relatives ❖ Cultural differences European american Shield from death Avoidant, indirect, vague Mexican Embrace death Straightforward Direct Factual Found less likely to endorse universality and non-functionality