psyc 302 quiz 3

reasons 2 study infancy

○ 1. Rapid change occurs in perception, action, learning, + cognition in 1st two years of life ○ 2. Infant development - intertwined b/t 4 domains (ie. improvements in visual abilities occur in 1st few months, enable infants to see more ppl + objects -> greatly increasing opp to learn new info!) ○ 3. Majority of research recent on perceptual + motor development on infancy/childhood ○ 4. Methods using to investigate infancy in 4 domains diff from older child

intermodal matching: is it all learning

some intermodal matching may be present even without learning -gave babies two diff types of teething toys (nubby vs plain pacifier) -counterbalanced 1/2 received nubby and then 1/2 plain -infants matched their looking time with the toys in their mouth -most perceptual learning via experience

motor milestones

- Prone,lifes head = 0-0.5 mos ● Prone, chest up, uses arm for support +rolls over - 2-4 1⁄2 mos ● Supports some weight w/ legs 3-6mos ● Sits iwthout support - 4-7 1⁄2 mos ● Stands w/ support 5-10 mos ● Pulls self to stand - 6-10mos ● Walks using furniture to support 7mos - 13 mos ● Stands alone easily 10-14 mos ● Walks alone easily 11 mos - 14 mos

auditory narrowing

- infants very sensitive to musical patterns and to differences in human speech -more sensitive to these differences than are adults -study: presented salish, hindi words, when they tasted salish babies at 6 most able to tell these sounds apart, but at 10-12 most, they can't tell them apart but at 11-12 most ppl can still tell them apart if they had exposure to it

auditory localization

- ​perception of location in space of a sound source ○ NB bad at determining spatial location of sound bc they need to rely on diff in sounds that arrive at both ears ○ Heads are small - timing + loudness in info are smaller for infants; development of auditory spatial map (mental representation of how sounds are organized in physical space) requires multimodal experiences , through which infants become able to integrate info from what htey hear with info they see and touch ● Infants adept at perceiving patterns in streams of sound they hear (subtle difff in sounds of human speech)

human learning

-how do humans learn -social learning -episodic learning (learning from one event, is enough) -rational learning (extend logic to new situations) -classic & operant conditioning -memorization (rote learning)

infant learning

-how is infant learning diff than adult learning -poverty of experience, changes the way they learn -infants use many learning mechanisms throughout development

statistical learning

-detecting statistically predictable pattern in stimuli -ie. when mom puts her hat and miss on, it's time to go outside -but learning can be much more powerful than that -speech -music -visual perception -brain is filing in gaps of lack of visual perception -more powerful in infants > adults -word segmentation -there are no consistent pause: how do infants learn what individual words are? -recall werker & tees: younger infants are sensitive to non-native speech distinctions; older infants are not -when older infants are familiarzed to unimodal distribution, they fail to discriminate hindi phonemes -they are familiarized to a bimodal distribution ● Goldilocks effect - avoiding patterns either too easy or too hard suggests infants allocate attention diff to diff learning problem, preferentially attending to those patterns that are most informative

sticky mittens

-giving prewriting infants ability to grasp objects changes their interest in the objects -this manipulation affects infants even a year later -two diff groups of babies: those w/ active training (where had sticky mittens and allowed to explore toys) and passive training (had mittens but no velcro) -those w/ sticky mittens explored manual manipulation of the toy 15 months later -3 month old infants who were actively trained (with sticky mittens) wee more manually engage w/ the toy at 16 months

intermodal perception

-infants and adults to match what they perceive in one sensory domain into another domain -ability to match stimuli from diff sensory modalities ie. silent speech/ lip reading, you're able to guess what is that auditory correlate -these abilities appear to be present form the earliest ages tested -as early as 2 mo, infants shown to match sound of what they're hearing with appropriate visual display -some of most influential evidence of intermodal matching comes from infants abilities to match heard and seen sppech -moreover infants appear to detect mismatches between heard and seen speech, even from languages which they are unfamiliar -played for infants speech sounds from hindi that either congruent or incongruent w/ videos

learning through motor development

-infants' increasing motor skills change their cognitive and perceptual abilities -think dynamic systems theory

associative learning

-learning that stimulus co-occurs with another stimulus

cultural variation in motor development

-motor development is highly variable across cultures -figure on previous slide consists of north american norms -ie china, indigenous, pals of Paraguay - delays motor development -indigenous pals of kenya - positive -Diapers (naked vs cloth diapers vs disposable diapers)

motor development

-newborns' motor skills consist predominantly of reflexes 1. grasping 2. rooting (opens mouth and turns face over hand) 3. sucking 4. swallowing 5. tonic neck reflex - whenever infant turns her head to side, the arm on side of head move out, and the arms/leg other side of head goes closer ..some of which last for entire lifespan such as coughing, sneezing, blinking, withdrawal from pain

perceptual learning

-not exclusive from other types of learning -infants ability to pick out regularities in their environment and associate -association b/t two events is learned over time -intermodal matching (ie visual correlates of auditory stimuli; gustatory correlates of visual stimuli) -infants learn to associate sight of dog with sound of barking ● Infants actively search for order + regularity in world around them; learn great deal from simply paying close attention to objects and events they perceive ● Differentiation: ​extraction from constantly changing stimulation in enviro of those elements that are invariant or stable ○ Discovery in ​affordances: ​possibilities for action offered or afforded by objects and situation ○ Ie. small objects (not large) have possibility to be picked up ○ Discover them by figuring out relations b/t their own bodies + abilities + things around them ● Underlies some intermodal perception- have yet to learn to relate unique sight of face w/ unique sound of her voice (3 1⁄2 mos) , need ot learn which particular sights and sounds go together

habituation

-type of non-associate learning (one stimulus at a time) -with repeated exposure to same stimulus, response declines -why is this an important tendency? -measuring looking time -dishabituation

infant face scanning

-we know from previous research that infants prefer to look at the eye region of face (except for a short period between 8-12 most) -but infants look more to mouth when watching mismatching speech (we do this too as adults) -dubs SUCK -english learning babies listening to hindi sounds; congruent = eyes; incongruent - switch -6 most old can tell apart even tho they don't have experience -infants have expectations what auditory speech should look on a face -6 m english learning infants looked more to mouth region when watching incongruent hindi videos ● And more to the eyes when watching congruent videos (just as they and adults usually do) ● Evidence that infants detect content mismatches even in unfamiliar languages

scale errors

-​attempt by young child to perform action on miniature object that is impossible due to large discrepancy in relative sizes of child and object (ie sit in doll sized chair or small toy car) -> fails to take acct relation b/t own body from +size of target object from a failure to integrate visual info represented in two diff areas of brain -> action

taste and smell

NB prefer smell of natural food source for human infants - breast milk, sweet scents, also can recognize their mothers

sensation vs perception

Sensation = sensory organs' detection of physical signals in enviro: auditory system; ear detecting sound waves Perception = organization and interpretation of sensory info into coherent understanding of objects, individuals, events

reaching

one of most obvious ways that motor developing affects cognition and perception is through reaching 1. Pre-reaching (prior 3-4 mos) 2. Jerky/undercontrolled reaching (4-7 mos) 3. Successful reaching (7 mos)

proposed mechanisms of perceptual narrowing

● 1) NB can discriminate static images of its mother's face from stranger if it has been exposed to its mother's voice + face in combo (not when there is no combo) ○ Face + speech perception linked from early age ○ PET - radioactively labelled substances which introduced bloodstream to visualize neural activity - reported adultlike brain activation when 2 mos presented w/ face+ faces also activated areas devoted to language in adults ● 2) discriminatory learning occurring at subordinate or individual lvl ○ Infants learned faces using both pic of face + name - increase ability to discriminate faces later + led to better discrimination of new monkey faces

article 2 experiment 2

● 2nd experiment: whether 8 mo could perform more difficult statistical computations required to distinguish words (recurrent syllable sequences) from syllable strings spanning word boundaries (syllable sequences occurring more rarely) ○ See if they can distinguish word internal syllable pair like pretty, from word external syllable pair liky ty#ba ○ 8 mo familiarized w/ 2 min of continuous speech stream etc , test items for each infant consisted of two words and two part words (joining final syllable of word to first two syllables of another word) ■ Judged as novel if infants had learned word with sufficient specificity + completeness that sequences crossing a word boundary were relatively unfamiliar ● RESULTS: infants showed significant test-trial discrimination between word + part word stimuli with longer listening time for part words ○ 2min sufficient infants to extract info abt sequential statistics of syllables ○ Novel preference can't be attributed to total lack of experience w/ three syllable sequence -> infants succeeded in learning and remembering particular groups of three syllable strings these strings containing higher transitional probabilities surrounded by lower transitional probabilities ● Usually infants in more natural settings presumably benefit from other types of cues correlated w/ statistical info ● CONCLUSION: infants possess experience dependent mechanisms that may be powerful enough to support word segmentation but also acquisition of other aspects of language

pattern perception

● 7 mo perceive subjective square -> integrate separate elements to perceive whole ● Even NB can do so if motion cues were added ● Infants able to perceive coherence among moving elements ● NB show preference for moving-lights depiction of biological motion over one of non-biological motion ● Despite limited acuity + lack of visual experience - NB are attentive to configuration of elements in own visual world

self locomotion

● 8 mos self locomotion: ​ability to move oneself around in enviro ● Usually crawling - belly crawling or inchworm belly flop -> hands and knees crawling (less effort+ faster) ● 11-12 mos, walking independently: keep feet wide apart, increasing base of support, ○ 60% feet on ground ○ Practice is vital to work weak muscles + precarious balance ● Infants adjust their mode of locomotion according to their perception of properties of surface they want to traverse

touch

● Active touch - oral exploration = 1st few months , infants mouth and suck their own fingers + toes / every other objects ● 4mo - infants gain greater control over hands and arm movements, manual epxloration increases + gradually takes precedence overo ral xploration ; actively rub, finger, probe, and bang objects and hteir actions become increasingly specific to properties of actions (rub textured, bang rigid ones)

rational learning

● Adults use rational learning extensively ● Infants are surprised when expectations are violated ● Violation of expectancy procedure: ​procedure used to study infant cognition in which infants are shown an event that could evoke surprise or interest if it violates something infant knows or assumes to be true ○ Study: habituate young infants to sight of screen rotating 180 degrees, then box was placed in path of screen; in possible event, screen rotated up, occluding the box and stop when it reach top; in impossible - screen rtoated up and continued through 180 degrees appearing to pass through the space where box was and infants looked longer at that! ○ We see whether or not infant looks longer demonstrating expectations are violated ● study : 50 red pingpong balls and 4 whites ball ○ Infants lookedl onger when experimenter removed white balls from the bx than when she removed red balls

perceptual narrowing

● At birth infants have broad perceptual abilities ○ Differentiation between individual faces of their own and diff ethnicities 9 mo and between individual faces of other species) ○ Differentiation b/t sounds in their own and other languages ○ Differentiation b/t musical rhythms form their own and other culture ● These differentiation abilities decline in first yr of life, as infants begin only to pay attention to differences in stimuli that are relevant for them ○ What mechanism of neural development - SYNAPTIC PRUNING!! ■ Causes behavioural phenomenon of perceptual narrowing

Article - development of phonemic perception

● Development of phonemic perception characterized by decline in discrimination of pseech sounds not present in one's native language ● Native language experience functions to tune, maintain, and facilitate perception of phonemes ● Substantial evidence suggesting specialization occurs 6-12 mo + dependent on perceptual exposure to native (opposed to nonnative) phonemic contrasts ● Ie. decline in ability of english speaking infants to distinguish hindi phonemic contrasts Ta and ta from 6-12 mos ● There is also environmentally facilitation of contrasts infants have experienced

article: neural correlates of perceptual learning

● ERPs - reflect electrical activity of simultaneously active populations of neurons in response to presentation of image/sounds ● Study: electrophysiological response discriminates both native and non native speech contrasts at 7 mo, but at 11 mo, infants could be clearly divded into two groups ○ Despite decline in ability to discriminate nonative contrasts, neural differentiation of ability is maintained at 11 months ● Adult like neural activity not present until 12 mos ● Neural differentiation of familiar vs unfamiliar monkey faces at 9 mos ○ Amplitude of ERP components to index face processing in infants differentiated among familiar + unfamiliar front and profile human faces whereas response to monkey faces only differentiated between familiar v nfamiliar -> response to human was more specific

development of perception of musical rhythm

● NA - simple duration ratios; bulgarian - metrical structures ● Adults can identify violations in music that is simple but not complex metrical structures ○ Bulgarian can identify complex ● 6mo NA can discriminate violations in both complex + simple rhythm until 12 mos of age where it becomes adult like however if they are briefly exposed to music containing complex metrical structure, they are able to later perceive violations later

social knowledge

● Emerges relatively early - behaviour of others is purposive + goal directed ● Only for humans ● Older infnats predict what human hand would do next, moving eyes to goal object before hand actually moved ● Infants understanding of goal directed of another is related to their own experience achieving a goal; ● Study: infants were habituated to hand reaching for ball on one side of display repeatedly; infants hwo saw hand reach foro ther objectl ooked longer than those who saw it reach for ball (regardless of position of ball) 0 babies interpreted orginal reaching as object directed ● Older infants even attribute intentions and goals to inanimate entities if objects seem to behave like humans ● Blob object responds contingently to infants; they tend to attribute intention from it ● Younge infants seem to attribute intention w/ respect simple displays involving small objects ○ Study: viewers of climber event - infants readily interpret in terms of inentional action; 1st see ball ast trying to move up hill, but then rolling back thereby failing to achieve goal abt reaching top; on some trials after ball starts to roll back, triangle appears below ball and seems to push it upward helping it get to top, on other trials cupe appears to front of ball and hinders it by seeming to push down hill ■ Babies looked longer when climber approached hindered indicating by their surprise understanding response but what climbers response might be ● Infants exhibit preferences for particular individs and objects based on their actions

article - development of face perception

● Hypothesized: faces not consistently present in infaint's early enviro decline b/t 6-9 mos ○ VPC - participats are first familiar to single stimulus and then is paired w/ novel stimulus ○ 6 mo old exhibited novelty preferences for monkey faces; but 9 mos didn't ○ Younger infants exhibit more broadly tuned face processing sys that can discriminate among exemplars w/in multiple categories of faces , and sys becomes more specific and less flexible w/ age ○ 3-6 mos exhibit differentiation of faces from other ethinic groups, whereas 9 mos only show differientation within own ethnic group ● 9mos old maintained ability to discriminate monkey faces if they had picture book of monkeys ○ Face processing abilities develop on basis of specific type of faces present in visual enviro

other aspects of infants' vision

● In addition to their low visual acuity and poor colour differentiation, young infants' vision differs from that of adults in other ways ○ Visual scanning ■ Irregular saccades (stop motion films) ○ Internal detail ■ 1 mo olds typically scan perimeters of shapes ■ 2 mo have begun examine internal details of shapes 2-3 mo, infants able to track moving objects smoothly (only if it's moving slwoly) ● Visual scanning is restricted - for complex shapes, stare at outer edges

article: development of intersensory perception

● Infants 4,6,8,10 mo viewed two side b side images of vocalizing monkey faces while listening to one of two vocalizations ○ Younger infants were able to correctly match vocalization they heard w/ monkey face making vocalization thru looking preference for sound-face match ○ 8-10 no sound face match made ○ Perceptual narrowing operates in development of intersensory perception as well as unimodal visual and auditory perception

face preference

● Infants are more attracted to faces than to non-face objects, such as bullseyes ○ This preference appears to extend from their preference for objects w/ more info on top than on bottom ○ Like rightside up face > upside down (bc amt of detail) ● Infants face preferences quickly develop, and infants prefer looking at their own mothers' faces over unfamiliar females faces within days of birth (even if it's ethnicity matched, aged matched, etc) ● INFANTS WHEN PREFER LOOKING AT FACES WHEN ADULTS HAVE RATED THOSE FACES AS MORE ATTRACTIVE ○ What causes adults to find some faces more attractive than others ■ Symmetry ■ Averageness (average of all the faces throughout development; more familiar to us; the average of us to be more attractive)

music perception

● Infants sensitive to music, when adults sing to infants they do in a characterisic fashion which tends to be slower, higher pitched, to suggest more positive affect than does singing toward adults ● Infants prefer infant directed singing over adult directed singing (more attentive to moms singing than speaking) ● Infants are able to remember what they hear ,recognizing musical excerpts several weeks after first being exposed to them ○ Tone, timbre, pitch, tempo ● Similar to adult music perception - preference for consonant intervals over dissonant intervals ○ Consonant more pleasing ● Infants pay more attention to consonant version of piece of music, not due to musical experience bc its demonstrated across species and NB ● Diverge from adult: infants can make perceptual discrimination that adults cannot with melodies ○ Study: both infants + adults noticed changes that violated key of melody, but infants noticed changes that stayed within key of melody ○ Heightened musical sensitivity bc lack of implicit knowledge

preferential looking

● Infants, like adults, choose to spend more of their time looking at objects and events that are interesting stimulating, or familiar

Classical conditioning

● Learning to associate a neurtral stimulus with a stimulus that evokes a certain response ● Pavlov and his dogs ● Unconditioned stimulus (food) ● Unconditioned response (salivation) ● Conditioned stimulus (bell) ● Condiioned response (salivation) ● Conditioned citrus scent can be conditioned to elicit head turns in 30 days olds ● Paired scent of lemon to a massage to baby's neck or face (pleasurable and elicits the)

operant (instrumental conditioning)

● Learning to associate one's own behaviour with an elicited response ● Positive reinforcement - mobile moves more when foot is moved more ● Operant condition can be observed in neonates as well as older infants ● High amplitude sucking procedure can be used to demonstrate operant condition ● More they suck, they perceive positive stimulus

review SAFFAN, ASLIN &NEWPORT

● Measured infants' use of statistical cues to word boundaries ● Using transitional probabilities to figure out what is a word or not a word in a language ● Familiarized infants to stream of nonsense speech (bidakopitakala) ● No spaces between syllables, or intonation cues ● Tested infants w/ ○ Real words from that nonsense speech ○ Non words comprised of same syllables but in wrong orders ● Infants look significantly longer when non-words (novel) were played than when real words (familiar) were played ○ Non words - composed in wrong order of familiar sounds ○ So they infants paid attention to order

motor development-> visual development

● Motor development has clear effect on visual development ○ Stick mittnes -> improved visual understanding of 3D objects ○ Walking -> more visual info than crawling

Core knowledge

● Not all ifnants knowledge is product of leanring ● Infants appear to have knowledge abt core set of principles ○ 1. Objects ○ 2. Agents- individuals can do actions ○ 3. Numbers ○ 4. Geometry ○ 5. Social (us vs them) ○ 6. Moral ● Objects: Infant's knowledge about the physical world is not limited to what they know and are learning about objects. Even in the first year, infants can understand that objects do not float in midair. ● Infants are surprised by block in mid air bc it's physically impossible (3 mos) so they know that OVERALL: Not all infant knowledge is based on learning, it can be innate

object segregation & common motion

● Object segregation: ​identification of separate objects in visual array; perception of boundaries between objects ● Kellman + spelke - 4 mo presented with two pieceso f rod moving on each end of block of wood or as single rod moving back and forth behind block ○ After habituatining to display, infants look longer at two rod segments than at single rod b) indicating that they find single rod familiar but two segmenets novels - if they first see a display with no movement, they look equally long at two test displays (long rod, and rod broken in two pieces ○ Common motion: ​two segments always moved together in same direction + at same speed ■ Leads infants to perceive disparate elements moving together as parts of a unitary object; dosn't matter if two parts of objectm oving behind block differ in colour, texture, and shape, nor does it make much diff how they move ■ Draws their attention to relevant aspects of scene- moving pieces rather than block ■ 2 mo of age show any evidence they use common motion to interpret occluded rod as single option

face discrimination

● Once their visual systems have more fully developed, infants in some ways have better visual discrimination than do adults ○ This is true for faces ■ Individual human faces vs individual monkey faces ■ Individual human faces from diff ethnicities

imitation

● One of the most powerful ways that infants learn is by imitating others ● Perhaps as early as immediately after birth ● Tongue protusion; bbs stuck out their tongues too; but also exists in non human primates ○ Emerges early across species ○ Is it reflex or imitation ● Not NB don't always imitate ● Replications of NB imitation studies have fialed ● Mirror neurons which can respond in kind ● Infants can be picky abt whom they imitate ● We tend to imitate individs who look like us or more familiar with or have been accurate in past, whom we're attracted to ○ Most likely to imitate parents ○ Ingroup, ○ Accurate - giving them info that is true ● 14 mo old infants more faithfully imitate members of their ingroup ○ Faithful imitation = imitation that corresponds both in form and goal to what individual does ● Randomly assigned to ingroup or out group condition ○ Had a guy read a story in their language(englisH ) ○ Outgroup: person read story in their foreign language ○ And watched experimenter push lamp with head or hands ○ And bbs to do what the man did afterwards ○ Bbs who watched ingroup speech, faithfully imitated adults ○ Outgroup: bbs would more likely use their hands ● Neural underpinnings of imitative learning - ​mirror neuron sys - ​ventral premotor cortex in non humans - ○ See patterns of neural firing when infants observing an aciton that is similar to those they display when they are performing same action

depth perception

● Optical expansion: a depth cue in which an object occludes increasingly more of bg, indicating object is approaching - visual image of object increases in size as object comes toward us ● When image approaching object expands symmetrically, we know object is headed right for us -> duck ● Infants as young as 1 mo blink defensively at an expanding image that appears to be an object heading toward them ○ Preterms had delayed this - maturation crucial + postnatal visual for mental achievement 1. Binocular disparity: ​difference between retinal image of object in each eye that results in two slightly diff signals to display ○ Closer object we r looking at, greater disparity between two images; farther away object, les disparity 2. Stereopsis: ​process by which visual cortex combines differing neural signals caused by binocular disparity, resulting in perception of depth ○ 4 mos age - complete w/in few weeks due to maturation of visual cortex 3. Monocular depth cues: ​perceptual cues of depth (relative size and interposition) that can be perceived by one eye alone (6-7 mos) ; pictorial cues bc used to portray dept in pic ● Infants will reach toward whichever tow objects i nearer ○ 7 mos would reach toward longer side, indicating that they perceived it as being nearer (rather than 5 mos), providing htey use relative size as cue to depth

object perception

● Perceptual constancy : ​perception of objects as being constant size, shape, colour, and so on, in spite of physical differences in retinal image of object ● Empiricists - perception of constant size + shape of objects as function of spatially experiencing our enviro; nativists - perceptual regularity stems from inherent properties of nervous system ● Nativist supported by research of perceptual constancy in NB + young infants ○ Infants looked longer at new cube which was twice as big as old but twice father aware ○ perceived multiple presentations of original cube as single object of constant size, even tho retinal size varied thereofre visual experience is not necessary for size constancy

REACHING tb

● Pre reaching movements: ​clumsy swiping toward general vicinity of objects they see ● Around 3-4 mos age, begin to successfully reach for objects ;although grabs fail more often than not ● Sticky mittens - > infants increased interest in objects + earlier emergence of ability to reach independently; improved ability to interaction w/ objects give s infants additional opportunities ot learn abt social world (how ppl interact w/ objects) ● 7mos - ability to sit independently, reaching stable + trajectory is consitently smooth + striaght to target ● Increased opportunities for object exploration ramifications for visual perception - infants w/ better siting + manual skills are better at perceiving complete 3d objets from limited view ● Vision not necessary for accurate reaching; infants can nab something that is making a sound ● With age = practice, infants reaching shows signs of anticipation (open fingers + adjust hand to orientation) ● 19 mo - approach to an object is affected by what they intend to do after they get it Reach faster for object they plan to throw than for one they plan to use in more precise faction

auditory development

● Review: what do we know abt developing auditory sys ○ In utero ○ Immediately after birth? - auditory acuity is just as good as adults ● Infant auditory sys is very well developed (auditory acuity is similar to that of adults ● NB turn their heads toward direction of sound ● Infants auditory localization is not well developed beyond side to side discrimination

vision

● Vision is human's dominant sense (in most situations) ○Most daily activities, vision is more important ○ Thermal detection - tactile dominant ○Dogs visual not as good as auditory stuff ○ Exceptions: Difference between how difficult is if the're talking to the phone to you or just lip voicing to you -> auditory would be better ● Myth or truth -Infants cannot see very well -Infants cannot see in colour

colour vision

● We can use preferential looking to determine extent of infants' colour vision and their visual acuity ○ Colour vision Visual acuity ■ 3 month old infants - prefer red/yellow colours over blue/green colours ■ Infants look longer at red (longer wave length) colours) ■ 1 month old infants show no such preference (but they do prefer bold colours)

visual development

● What causes infants' lower visual acuity and colour vision? ● Review: two types of retinal photoreceptors ○ Rods - activated in low light ○ Cones - activated by wavelengths of diff colours ● Infant's cones are less dense and smaller ○ Less light is processed than by adults (2% vs 65% of light that reaches the fovea) ○ Colours are more poorly differentiated ● 2-3 MOs infants colour vision is same to adults, ● 4-5 mos prefer blue + red like adults + perceive boundaries b/t colours + discriminate b/t two shades ● Around 6 yrs, infants w/ be like adults w/ visual acuity

article 2: experiment 1

● hypothesis: asked whether 8 mos infants can extract info abt word boundaries solely on sequential statistics of concatenated speech ○ Infants exposed to auditory material that serves as potential learning experience ○ Two types of stimuli: 1) items contained w/in familiarization material 2_ items that are highly similar but not contain w/in familiarization material ○ Infants control duration of each test by their sustained visual fixation on blinking lights ○ If infants extracted crucial info abt familiarization items, they may show differential durations of fixation (listening) during two types of test trials ● Experiment: 8 mo infants were familiarized w/ 2 min of continuous speech stream consisting of four 3 syllable nonsense words repeated in random order no acoustic info abt word boundaries , no pauses, stress differences, ○ Only cues to word boundaries were transitional probabilities between syllable pair which were higher within words (bida) than between words (kupa) ● Each infant presented w/ repetitions of one/4 three syllable strings on each test trial ○ Two were words from artificial language presented during familiarization + two were three syllable nonwords that contained same syllables heard during familiarization but not in order which they appeared as words ● Results: infants showed significant test trial discrimination between words and nonword stimuli, with longer listening times for nonwords ○ Novelty preference indicates 8 mo recognized diff between novel + familiar orderings of three syllable strings

visual acuity

● likewise - we can use preferential looking to determine infants' visual acuity ○ 1 month would prefer to lookingg at patterned images over grey images ○ However when lines in pattern are close together, infants do not show a preference over patterns vs grey ○ Infants have poor visual acuity, the pattern blurs into solid if it's not as contrasting ● In their first month of life, infants visual acuity is approx 20/120 (1⁄6 of that of a normal adult) ○ 20/120 means that if u view object that is 20 units away, that it looks at you to as 120 metres away ○ This acuity is equivalent to being only able to decipher top line