PSYC 304 Lecture Notes - Fall 2024 PDF

Ryan Stainsby Fall 2024 PSYC 304 LECTURE NOTES Lecture 1a - Introduction and What is Childhood - September 9 Course Outline - OH: mondays, 12-1 pm or by appointment - Email fo...

Ryan Stainsby Fall 2024 PSYC 304 LECTURE NOTES Lecture 1a - Introduction and What is Childhood - September 9 Course Outline - OH: mondays, 12-1 pm or by appointment - Email for other times (since class during that hour) - Midterms are MC, final exam too (final exam is cumulative) What is Childhood? - Childhood - Legal: Human beings below the age of 18 - Biological: humans that are physically immature - Psychological definition: ? - Sense that there is a difference between adults and children psychologically What it Means to be a Child - Dependent on Adult Caregivers - Longer childhood compared to other species - Makes children very vulnerable, thus caring for them is very time consuming - Long childhood - Many primates have quite lengthy childhoods - Humans still have longest childhoods amongst primates - Due to a large brain, narrow hips trade-off - Large Brain, Narrow Hips Trade-Off - Our brain are large for our size and more complicated/neuron dense than any other animal - Larger brain necessitate larger heads - At the same time, evolution of ability to stand upright (bipedalism) favored narrow hips - Necessitate smaller heads to pass through birth canal - Conflict between large head and narrow hips - To solve conflict, babies evolved to be born earlier - Brain continues to develop once born - Fundamentally about Learning - Born not fully formed also allows for more learning - Adaptive for actually maximizing learning - Many aspects of childhood demonstrate that children are adapted to focus on learning  - Highly curious - Highly suggestible, not critical thinkers - Readily imitate others - Overestimate own abilities - Brains are malleable - Focus on learning is only possible if taken care of by adults - Child Development - Process of learning of perceptual, cognitive, emotional, and social capabilities that allow an individual to grow from dependence of infancy to independence of adulthood Topics - Early development - Visual and motor - Cognitive development - Learning about world, social cognition, language - Social development - Emotional, attachment, family and peer relationships, moral - What develops and when - ***will be lots of age memorization Why Study Child Development? - Raising children - Helps answer question as to how to raise children - Ranges from small questions to large, life changing questions - Choosing social policies - Helps inform these policies that impact children - Eg: should children be allowed to play violent video games? - Studies found very small impact on aggression - Or: screen time/social media’s impact on children? - How much, what kind, school policies - Understanding human nature and individuals - Child development research vital to understand how nurture and nature shape human psychology - Can help explain individual differences - Understand people and build empathy skills  Lecture 1b - Visual Development - September 9 - What do babies see? - Historically assumed that infants’ vision was almost non-existent and barely functional - This is incorrect - From birth, they visually scan environment and pause to look at stuff - Can’t ask babies what they see, so have to get creative Methods in Infant Research - Two main paradigms - Preferential looking paradigm - Habituation paradigm - Preferential Looking Paradigm - Assess infants’ preference for one stimuli over another - Present baby with 2 stimuli beside each other at the same time - If they look at one more than the other, it means… - They can distinguish between the two - Have a preference for one over the other - What is Interesting to Infants - Prefer to look at stimuli that are more complex - Or more saturated in color - Also prefer things that are familiar - Habituation Paradigm - Paradigm takes advantage of babies’ natural preference for novelty - Assess infants’ ability to discriminate between stimuli - Habituation phase: repeatedly present infant with a stimulus until habituate - Reduced or stopped response, when infant is bored - Test phase: present habituated (old) stimulus with a new stimulus - Dishabituation: baby shows greater interest from preferential looking at the new stimulus - Indicates they can tell the difference - If look equally, can’t say much (assume can’t tell the difference) - Familiarity vs Novelty - In general, infants show a preference for familiar stimuli - What we see in preferential looking - Prolonged exposure to a stimulus will cause infants to shift their preference to a novel stimulus - Summary - Preferential looking  - Two stimuli side by side - Assess preference for one - Prefer familiar and/or complex stimuli - Habituation - Habituate to one stimulus, then present it with a new stimulus - Assess ability to distinguish - Prefer novel stimulus Visual Acuity and Color Perception - Visual Acuity - Sharpness of visual discrimination - Assessed in infants by using preferential looking paradigm - Present series of paddles with increasingly narrow stripes - Alongside a gray paddle - Infants should prefer the striped paddle - Start with largest stripes, then move down to assess limit of acuity - At birth, infants have poor visual acuity - Prefer to look at patterns with high visual contrast - Don’t discriminate between lower contrast stimuli - Babies can see in some detail for a distance of about 8-10 inches - Close to distance to mother’s face when breastfeeding - Why? - Due to immaturity of cone cells in infants’ retinas - Cone cells: light sensitive neurons involved in seeing fine details and colors - By 8 months they have adult like visual acuity - Visual ability is the least developed sense at birth! - Color Perception - Birth: infants see in gray scale - 2 months: color vision appears (usually see red first) - 5 months: adult-like color perception - Due to maturity of cones as well as visual cortex - Can discriminate between color categories and hues of the same color - How they tested hue discrimination - Use habituation - habituate red color - Test phase - either use green (different category) or a different hue - Visual Scanning - From birth: infants scan visual environment and pause to look at things - But trouble tracking moving stimuli - eye movements are jerky  - 4 months: able to track moving objects smoothly, as long as slow motion - 8 months: adult like visual scanning - Can smoothly follow object - Improved visual scanning due to brain maturation - Ability to visually scan is important - One of the few ways infants have control over what they observe and learn Face Perception - Why are babies so drawn to faces? - Newborns how a preference for faces or face-like stimuli (compared to non) - So do adults! - Think about learning a new language - Hypothesis 1: Is there a special innate face perception mechanism? - The fusiform face area (FFA) near the lateral occipital complex - Hypothesis 2: infants have a general bias for stimuli that are more “top heavy” versus “bottom heavy” - Top heavy - more interesting, complex action in top half - Testing Hypothesis 2: - Preferential looking paradigm - Showed babies: - Regular faces - Upside down faces - Scrambled, top-heavy faces - Scrambled, bottom-heavy faces - If faces special, babies should always prefer upright face - If general bias for top-heavy stimuli, should prefer BOTH upright face and scrambled top-heavy faces - Results: found that they prefer upright face AND top-heavy face - THEN they presented the upright face and top-heavy face - Found that infants showed no preference between - Seeing Mom’s Face - Infants very quickly learn to recognize and prefer their own mother’s face - Just a few days after birth, babies prefer their mother’s face compared to another woman’s face - Vision is not the only way they sense their mother’s smell - Smell is much more developed - strongly attuned to mothers smell - Most strong indicator of mom - Also use hearing - mom’s voice is heard when in utero - Becoming a Face Specialist - Over first year of life, infants become face specialists - Better at distinguishing between faces that are frequently experienced in environment - Worse at distinguishing between faces they encounter less - One way to show this is via the other race effect - Other-Race-Effect in Infants - Other-race-effect: people find it easier to distinguish between faces of individuals from their own racial group (than between those of other groups) - Also evident in infant, via study - Researchers recruiter Causcasian, Black, and Chinese infants - Habituated infants to face from own race OR face from another race - Then presented habituated face with new face from the same race - Measured ability to distinguish between the two faces - Results: - 3 month olds: easily distinguish between faces of all races - 9 month olds: better at distinguishing between faces of own race - Not innate, but rather exposure effect - During first few months of life, 96% of faces babies are exposed to tend to be females from own race - If infant is equally exposed to faces of different races, will not show other-race-effect - Also holds true for gender - Perceptual Narrowing - Tuning of perceptual mechanisms to the specific sensory inputs that infants encounter in their daily life - Improves perception of stimuli encountered often - Decline in ability to distinguish stimuli not present in environment - Present for several perceptual domains - Result of synaptic pruning - Synaptic Pruning - Synaptic pruning: elimination of synapses to increase efficiency of neural communication - “Use it or lose it” - Synaptogenesis: formation of synapses between neurons - Rapid synaptogenesis right after birth - Results in hyper-connectivity in the brain - Pruning across domains  - Pruning is different for different domains - Synaptic pruning occurs earlier for parts of the brain that develop faster - Sensory pathways prune the earliest - within a few months after birth - Language prunes afterwards - starting around 8 months - Higher cognitive functions after first few years of life - Face Perception in Children with ASD - People with autism spectrum disorders (ASD) often have difficulty with face perceptions - One hallmark of ASD is social disabilities - Toddlers with ASD preferred looking at geometric shapes over pictures of people - Opposite for neurotypical developing kids - Infants preference for non-faces could be an early indicator that the infant will later be diagnosed with ASD - Summary - Preference for faces from birth - Especially mother - From general bias for top-heavy stimuli - By 9 months, infants become face-specialists - Result of perceptual narrowing - Other-race-effect is present in infants Object Perception - Perceptual Constancy - Perception of objects as being constant in size, shape, color…etc - Despite physical differences in the retinal images of the object - Is perceptual constancy present from birth? - Perceptual Constancy in Infants - Study - Habituation paradigm with newborns - Habituation: repeatedly showed infant a small black and white cube - Cube showed at various distances on each trial - So created different retinal images between trials - Question: do infants perceive these as the same object or as different objects? - Test: show infants the original, small cube, and a larger, identical cube - Large cube was presented further away so that they could create the same size retinal image projected on retinas - Results - Infants looked longer at the larger but further away cube  - Indicates this is a novel stimulus - So this indicates that they saw the new cube as different in size from the original, smaller cube - Also means infant saw repeated presentations of original cube as constant in size - Suggests perceptual constancy is present from birth - Object Segregation - Ability to identify objects that are separate from each other - Determine borders between distinct objects - Movement is an important cue - Separate objects move independently of each other - Color is also an important cue - Different color indicates different objects - Object Segregation in Infants - Habituation paradigm with newborns and 4 month olds - Habituation: repeatedly watched video of a rod moving side to side behind a box - Question: do infants see the rod as a single rod or as two separate short rods? - Test: shown two rod stimuli moving side to side - The complete rod and the broken rod - If they see it as a continuous rod, should look at broken rod - Results - 4 month olds: preferred to look at broken rod - Indicates they understood rod behind box is one object - Newborns: looked the same amount of time at both rods - Indicates do not understand the nature of object behind box - Suggests that object segregation is not innate - Has to be learned with experience - Also relies on improvements in visual scanning (appears at ~4 months) - Depth Perception - Binocular disparity: difference between retinal image of an object in each eye - Results in two slightly different signals being sent to brain - Visual cortex combines differing neural signals caused by binocular disparity - Depth perception relying on binocular disparity is present at 4 months old - Sensitive Period for Binocular Vision - Sensitive period: a biological period during with certain kinds of experiences are necessary for an ability to develop normally - Sensitive period for binocular vision: from birth to age 3  - Depth perception from cue of binocular disparity is a natural result of brain maturation - So long as receive normal visual input from both eyes - If infants do not receive normal binocular visual input until age 3 they may fail to develop normal binocular vision - Will have life long difficulties with depth perception - Monocular depth cues: depth cues perceived with one eye - Eg: relative size or overlap - Perceived by 6 months old - Assessed using visual cliff - 6 month olds will not crawl over visual cliff - Younger infants will crawl over it - Suggests this aspect of depth perception needs to be developed through experience - Also relies on improvements in visual acuity Visual Development Timeline - Birth - Rudimentary visual scanning, poor acuity, preference for high contrast, gray scale, preference for faces vs non faces, perceptual constancy - 2 months - Color vision appears - 4 months - Object segregation, binocular depth perception appears - Sensitive period for binocular depth perception is 0 to age 3 - 5 months - Adult-like color perception - 6 months - Face generalists, monocular depth perception appears - 8 months - Adult like visual scanning, adult like visual acuity - 9 months - Face specialists - through perceptual learning Nature vs Nurture of Visual Development - Innate: perceptual constancy, preference for top heavy stimuli - Improve with brain maturation - visual acuity, color perception, visual scanning - Experience dependent - object segregation, face perception, depth perception  Lecture 2a - Making Sense of Visual Input - September 16 Review of Visual Development - Review - Preferential looking paradigm - Prefer more interesting, complex visual stimuli - Habituation paradigm - Prefer novel stimuli after habituation - - Back to Familiarity vs Novelty - Infants prefer to look at stimuli that are - More complex and saturated - Familiar objects - Can think about familiarity in multiple ways - “Natural” familiarity - stimuli infants experience often in their lives - “Lab-induced” familiarity - familiarize infant to new stimulus by first exposing it to them for brief time - Showing baby stimulus, just enough time to be familiar, don’t want to be bored by it - In this case, there is a preference for this stimulus - In the lab, length of exposure of initial stimulus determines preference - Short exposure = familiarity preference - Long / repeated exposure = novelty preference Intermodal Perception - Overview - Coordinated perception of a single object or event through two or more sensory systems - Often vision and at least one other sensory modality - We rely on vision a lot - Present very early on  - Combining Vision and Touch - Study done on newborns - Familiarized infants on pacifier they couldn’t see - Test pacifier was bumpy/spiky (not harmful) - Then presented images of both pacifier - Results - Newborn showed preferential looking for familiar stimuli - the spiky pacifier in this case - Shows ability to combine visual information with touch present from birth - Combining Vision and Auditory Info - Study done on infants - Preferential looking procedure - 4 month olds simultaneously watched two videos side by side - One video had someone play peekaboo - Other video had someone playing the drums - At the same time, they are hearing someone say peekaboo - No drum noises - Results - Looked longer at person playing peekaboo - Shows infants can integrate visual and auditory information - Important for language development because children need to understand speech sounds are linked with moving mouth Categorization - Categorization in Infancy - Categorization is present from infancy - as young as 3 months old - Study using habituation - Would habituate babies to cats - Test was a photo of a dog - Result was infants looked longer at the dog - Infants also seem to be able to form more general categories - Study on 6 month olds - Habituate them on photos of mammals - Test showed a non mammal - Infants looked longer at the non-mammal, indicating ability to discriminate between mammals/non - Perceptual Categorization - Infants group things together that are similar in appearance - Especially things that have similar shapes  - Study on 6-12 month olds - Showed them target object and shows that it rattles - Then infants playing with other objects were more likely to assume objects with a similar shape also rattles (fun/unexpected) - Also can determine based on texture and color, but more on shape than anything - Limitations - Difficulties understanding exceptions - Eg: animals that don’t have legs - Mistakenly categorizing objects together - Eg: planes are birds - Conceptual Categorization - Around 9 months old - Children begin categorizing objects based on shared function or behavior - Still mostly categorize based on perceptual similarities - 9 month olds have 3 general categories - People - Animals - Inanimate objects - Indexed by different reactions to members of each of these categories - Smile most/interested most in people > animals > objects - Importance of Categorization - Helps makes sense of the world by simplifying it - Interesting to know how young it starts - Allows children to make inferences and predictions about objects of the same category - Can influence what questions they will ask about objects - Beyond Infancy - By 2-3 years old, children start to form category hierarchies - Category hierarchies - organize object categories by set-subset relations - Allow for finer distinction among objects within each level - From highest to lowest: - Superordinate level - animals, plants, furniture…etc - Basic level - chairs, tables, cats, dogs…etc - Subordinate level - lions, lynxes…etc - Category Hierarchies - Basic level first - Objects at this level have the most obvious similarities  - Similarities at superordinate level are too large to understand, and similarities at subordinate level are too fine to understand - Thus basic level is the logical starting point Lecture 2b - Motor Development - September 16 Motor Milestones - Reflexes - Innate involuntary actions that occur in response to particular stimulation - Reflexes are adaptive - Some examples - Grasping - something near palm, close hand around it - Rooting and sucking - put object on side of face, will turn to it and suck it - Stepping - if hold arms up, will try to step on ground - Function of some is unclear - Tonic neck reflex - when head turned, that side extends and other side flexes - Not sure why this exists - Most reflexes disappear by 2 months of age - Some of them don’t - Coughing, sneezing, blinking, withdrawing from pain - Absent reflexes or ones that persist for too long can indicate neurological problems - Motor Milestones in Infancy - Major motor developmental tasks of a period - Happen in sequence, rarely out of order - But lots of variation in when in ages they are achieved - General order - Lift head - 1 month - Lie down and prop themselves up - 2-4 months - Rolling over - 2-5 months - Support weight with legs - 3.5-6 months - Sit without support - 4.5-8 months - Stand with support - 5-10 months - Pull self to stand - 6-10 months - Walks using furniture for support - 7-13 months - Stands alone (easily) - 10-14 months - Walks alone (easily) - 11-14 months - What about crawling? - Crawling - 7-8 months old - babies begin crawling - But babies have very different crawling styles - Crawling is not considered a motor milestone - Many healthy babies never crawl and skip right to walking - Motor milestones usually indicate critical for healthy development - Why do babies skip crawling? - Upper body or core weakness - Hypersensitive to texture of floor/carpet - Insufficient opportunity - needs enough time on the floor - Cultural Differences in Motor Development - Average ages of milestones are based on WEIRD samples - Western, educated, industrialized, rich, and democratic - Most people are not from these areas - Only 15% of world’s population - Example 1: Culture and Sitting - Considered normal from chart is 4.5 to 8 months old - Huge cross cultural differences in how long 5-month olds can sit independently - Italian had basically no infants who could sit alone - USA had some that could do a few minutes - Kenya had many that could do over 20 minutes - Why? 4 main kinds of places infants are left - Little postural support - Ground - Adult furniture - These require them to build core and sit alone - Lots of postural support - Child furniture - Being held by adult - Don’t need to overcome gravity - Earlier independent sitting in countries where infants spend more time in places with less postural support - Opposite is true in places with lots of postural support - Example 2: Culture and Encouragement of Motor Skills - Affected by how many opportunities infants have to practice - And how much motor development is actively encouraged - Some countries, infants are actively discouraged from crawling - Usually for safety or health concerns  - Or by motor development encouragement - Such as motor exercises in sub-saharan Africa - Example 3: Culture, Diapers, and Walking - Diapers affect infant walking - Infants show more mature walking when naked vs when wearing a diaper - All infants in study were used to wearing diaper - Cloth diapers had least mature walking ability - Implications of Cultural Differences - Context plays important role in motor development - Differences in course of development reflect environment infants are in Mechanisms Behind Motor Development - Overview - Motor development is governed by complex interplay between numerous factors - Brain maturation (historically only thought this) - Increases in physical strength - Physical abilities - posture control and balance - Perceptual skills - Changes in body proportions and weight - Motivation - All factors contribute to individual differences in motor development - Role of Weight Changes - Infants born with stepping reflex - Disappears at 2 months olds - Starts again between 7-12 months of age when learning to walk (average is 11 months) - Why does it disappear? - Hypothesis - infants gain weight faster than building leg muscles - Thus have insufficient strength to lift legs - Evidence - Infants who had weights added to legs stopped stepping despite having reflex - Infants who stopped showing reflex started stepping again when placed in tank of water - Showed due to weight change and not just cortical maturation - Why heavier babies tend to walk later - Role of Motivation - Infants are highly, intrinsically motivated to explore and learn - They persist despite failing  - Continue to practice new skills even though they posses skills that are sufficient to accomplish the same goal - Eg: learning to walk even if they can crawl - Look delighted when practice new skill - Even if parents don’t show usual excitement - Individual differences in motivation predict when motor milestones are achieved - Study - compared low/high motivation infants on when achieved milestones - Low motivation - moved infrequently, preferred low effort activities, require spur to move - High motivation - move frequently, prefer to do energetic activities, tend to move on their own - Demonstrated that those who tend to achieve some milestones early will achieve most milestones earlier - Mostly due to individual temperament/personality - Implications of Motor Individual Differences - Level of motor skills at 5 months predicted… - Intelligence at 4 and 10 years old - Academic achievement at 14 years old - Findings controlled for parent’s intelligence, supportive caregiving, and quality of home environment - Suggests that motor development influence cognitive development How Motor Development Enables Learning - Motor Development is Critical for Learning - Enables active learning about world - Specifically learning by trial and error - Facilitates development of skills in other domains - Reaching - 7 months old - able to sit independently and reach for objects - Has consequences for visual and social development - Reaching and 3D Object Perception - Reaching enables object exploration - In turn fosters understanding objects are 3D - Study done on 4-7.5 month olds - Assessed sitting and reaching ability - Habituation - presented with rotating object with only 2 sides displayed - Test presented them with two displays - One display showed prism rotated all around - Other was incomplete - just those two faces  - Results - Infants more advanced in sitting/reaching were more likely to look at incomplete display - Suggests motor skills development in sitting/reaching fosters 3D object perception - Reaching and Social Development - Reaching also facilitates social development - Study with placing objects in bucket - Watch video of person placing objects in bucket - 12 month olds showed proactive gaze towards the bucket - Indicates they understand the person’s intention - 6 month olds didn’t do this - Haven’t yet developed the skilled object reaching and manipulation to understand others - Showed infants ability to predict others actions relies on them being able to perform some of these actions - Reaching and Language Development - Skilled object reaching and manipulation enables greater interaction with caregivers - Caregivers then more likely to interact with them - Often will use words in this interaction - Infants are more likely to reach for objects in presence of caregivers - Reaching also enables vocabulary growth through this - Self-Locomotion - 8 months - most infants begin moving around on their own - Usually by crawling - Has consequences for visual and social development - Self Locomotion and Perception - Expansion of visual world - Babies who can walk/stand, their visual field gets much larger - Infants who develop self locomotion learn to integrate perception with action - Study with infants and walkways - Walkways were either shallow or steep - encouraged to crawl across both - Results - Perception of slope depended on crawling experience - Beginning crawlers attempted to crawl down both slopes - Experienced crawlers avoided steep slopes - Babies then made the same mistakes with walking as with crawling  - Failed to transfer learning from crawling to walking - Suggests infants have to learn how to integrate perceptual information with each new motor skill developed - Scale errors - Attempt to perform action on miniature object that is impossible due to huge size difference between object and child - Present until around 2 years old - Due to difficulty integrating visual information with action - Self Locomotion and Language Development - Walking enables… - Infants to carry objects to caregivers - Can get from another room and bring back - Increased interactions with caregivers and more sophisticated interactions - Vocabulary growth - learn new words - Thus early motor skills predict cognitive skill in later childhood  Lecture 3 - Cognitive Development - September 23 Previous Lecture Review - Intermodal perception - Integrating from more than one sense - present from very early on - Visual is most common - Visual and touch from birth, visual and audio by at least 4 months - Categorization - Category hierarchies by 2-3, children learn basic category first - Starts based on perceptual categorization (starts based on shape) - Starts very young, in infancy - Infants are born with various reflexes, most disappear by 2 months - Motor milestones are major motor developmental tasks in infancy - Not all babies learn to crawl - Motor development is based on many factors - Where children are placed (postural support) - Individual motivation - Other parenting practices - diapers, motor exercises - Body weight/proportions - Brain maturation - Individual differences in motor development predict later cognitive skill - New motor developments (such as reaching) foster greater communication with caregivers, which in turn fosters language development - Motor development also shapes social development and perceptual skills Piaget’s Theory - Jean Piaget - Father of field of cognitive development - 1920 - Binet institute on intelligence tests - Intrigued by children’s wrong answers (the kinds of mistakes they made) - Proposed that children’s thinking is qualitatively different from adults - Also proposed cognition grows and develops through series of stages - Overview of Stages - Sensorimotor - birth to 2 - Preoperational - 2 to 7 - Concrete operational - 7 to 11 - Formal operational - 12 and up - Properties of Piaget’s Stage Theory - Children at different stages think in qualitatively different ways - Thinking at each stages influences thinking across many topics  - There is a brief transitional period at the end of each stage - Stages are universal and order is always the same - Sensorimotor Stage (