A.   Skeletal Growth: Children of the same age differ in the rate of physical growth, and current body size is not an accurate indication of physical maturity; the best way to estimate a child’s physical maturity is to use skeletal age, by x-raying the bones and seeing how far the epiphyses (growth plates) have developed. (African-American children tend to be slightly ahead of Caucasian-American children at all ages, and girls are considerably ahead of boys in skeletal age.)

B.   Growth of the Skull especially rapid during the first 2 years; gaps called fontanels or 'soft spots' and sutures close over and harden as brain growth slows.

C.     Teeth first appear between 4 to 6 months of age. By age 2, the average child has 20 teeth. However, a great deal of variability in this area of development.

D.  FACTORS AFFECTING EARLY PHYSICAL GROWTH 

• Heredity affects height when environmental conditions are adequate. Weight is also affected by genetic make-up. However, the environment— especially nutrition—does play an important role.

• Environmental factors such as illness or poor nutrition.vCatch-up growth is physical growth that returns to its genetically determined path after being delayed by environmental factors.

• A baby’s energy needs are twice as great as those of an adult, and Twenty-five percent of an infant’s caloric intake is devoted to growth. If a baby’s diet is deficient in either quantity or quality of nutrients for a long period of this time,, growth can be permanently stunted.

• Breast-feeding offers many nutritional and health advantages over bottle-feeding. Breast-fed babies in impoverished regions of the world are less likely to be malnourished and more likely to survive the first year of life. Infants benefit from the antibodies and easy digestibility of breast milk.  However, because breast milk is easily digestible, breast-fed babies become hungry more often than bottle-fed infants, making breast-feeding inconvenient for many employed mothers, and some mothers cannot nurse because of physiological or medical reasons. Breast- and bottle-fed children in industrialized nations do not differ in psychological adjustment.

• Obesity: Infant and toddlers can eat nutritious foods freely, without risk of becoming too fat. The typical 'chubbiness' of the infant provides insulation that maintains the body temperature, and serves as a store of energy for the burst of activity of a newly crawling and walking baby.  Only a slight correlation exists between fatness in infancy and obesity at older ages and pediatricians only recommend restricting calories fro grossly obese infants.

• Malnutrition: 40 to 60 percent of the world’s children do not get enough to eat. Marasmus, a wasted condition of the body usually appearing in the first year of life, is caused by a diet low in all essential nutrients. Kwashiorkor is a disease usually appearing between I and 3 years of age that is caused by a diet low in protein. ron-deficiency anemia, a condition common among poverty-stricken infants and children, interferes with many central nervous system processes. Children who survive these severe forms of malnutrition grow to be smaller in all body dimensions and their brains can be seriously affected.  Early nutritional intervention is important, before the effects of early malnutrition are allowed to run their own course.

• Emotional Well-Being: Nonorganic failure to thrive, a growth disorder that shows up by around 18 months of age, is caused by lack of parental love. If the disorder is not corrected in infancy, some children remain small and have lasting cognitive and emotional problems.

E.  MOTOR DEVELOPMENT 

• The Sequence of Motor Development:  Although the sequence of motor development is fairly uniform across children, there are large individual differences in rate of motor progress. Motor control of the head precedes control of the arms and trunk which precedes control of the legs (cephalocaudal trend). Head, trunk, and arm control appear before coordination of the hands and fingers (proximodistal trend). Gross motor development refers to control over actions that help an infant move around in the environment, such as crawling, standing, and walking. Fine motor development involves smaller movements such as reaching and grasping.

• According to dynamic systems theory of motor development, mastery of motor skills involves acquiring increasingly complex systems of action. Each new skill is a joint product of central nervous system development, the movement
  possibilities of the body, the goal the child has in mind, and environmental supports and encouragements for the skill.
  When a skill is initially acquired, it is tentative and uncertain. The infant must practice and refine it so that the skill becomes smooth and accurate.   Each skill is acquired by revising and combining earlier accomplishments into a more
  complex system that allows the child to reach a desired goal. Studies show that infants are active problem-solvers in acquiring motor skills. They experiment and revise motor actions to fit changing task conditions.

• Fine Motor Development: Voluntary Reaching and GraspingMotor skills start out as gross activities and move toward mastery of fine movements. Voluntary reaching plays a vital role in infant cognitive development, since it opens up a whole new way of exploring the environment. . Early reaching is controlled by proprioception, our sense of movement and location in space that arises from stimuli within the body. Prereaching is the uncoordinated, primitive reaching movements of newborns. Voluntary reaching appears at about 3 months and gradually improves in accuracy. The ulnar grasp is the clumsy, reflexive grasp of young infants, in which the fingers close against the palm. The pincer grasp is a well-coordinated grasp that emerges at the end of the first year, involving the oppositional use of the forefinger and thumb.

• As demonstrated by the article on teaching infants with Down Syndrome to walk early, early motor skills are due to complex transactions between nature and nurture. Cross-cultural research shows that early movement opportunities and a stimulating environment contribute to motor development. Cultural beliefs vary concerning the necessity and advisability of deliberately teaching motor skills to babies. However, trying to push infants beyond their current readiness to handle stimulation can undermine the development of important motor skills. As infants’and toddlers’ motor skills develop, their caregivers must also devote more attention to protecting them from harm.

• Toilet training is best delayed, for most toddlers,  until the end of the second or beginning of the third year, when they can correctly identify and respond to signals from a full bladder or rectum and wait until they get to the right place to permit these muscles to open. These are physiological developments that are essential for the child to cooperate with training.

F.  BRAIN DEVELOPMENT  
At birth, the brain is nearer to its adult size than any other physical structure, and it continues to develop. While most neurons preformed before birth, growth of glial cells and myelinization of neural fibers, which make up half the developed brain's volume, far from complete. Neurons that arc stimulated by input from the surrounding environment continue to establish new synapses but neurons seldom stimulated soon lose their synapses, a process called synaptic pruning. 

• The cortex: The cerebral cortex is the largest structure of the human brain and accounts for 85 percent of its weight. It contains the greatest number of neurons and synapses, and it is the last of the brain structures to stop growing.The order in which cortical regions develop corresponds to the order in which various capacities emerge in infancy and childhood. One of the last regions of the cortex to develop and myelinate are the frontal lobes, which are responsible for thought and consciousness. (This area of the brain continues to develop until the mid-20's!)

• Lateralization is the specialization in function of the two hemispheres, or sides, of the cortex, left and right. Lateralization begins early in life and is molded by early experience.Language development plays a role in lateralization. The development of 'handedness' is related to lateralization but does not usually develop until late toddlerhood or early childhood.

• Brain plasticity is the ability of other parts of the brain to take over the functions of a damaged part. During the first few years, the brain is more plastic than at any later time of life, perhaps because many of its synapses are not yet established.

• The existence of sensitive periods in the development of the cerebral cortex has been demonstrated in animal studies, but is less clear in human development.  The brain grows in spurts, much like the infant's bodily growth, in which there are gains in brain weight and skull size, as well as changes in neural activity. Massive production of synapses may underlie brain growth spurts in the first 2 years; development of more complex and efficient neural networks may account for later ones. 

• The infant's brain is especially vulnerable to stimulation and deprivation. Learning new skills is rapid and children deprived of rich and varied experiences available in caring family environments may suffer permanent imcognitive impairment. The more extreme and longer lasting the early deprivation, the harder it is to overcome with later enrichment. However, overstimulation can also be a problem, as seen in the video on pre-term infant care.

• Changing States of Arousal:  During the first 2 years, the organization of sleep and wakefulness changes, and fussiness and crying decline, and infants remain awake for longer daytime periods and need fewer naps. Although brain maturation is largely responsible for changes in sleep and wakefulness, the social environment also contributes. By the middle of the first year, melatonin secretion in the brain is greater at night. The text discussed the practice of isolating infants to promote sleep, which is rare outside of the developed Western nations.

G.   PERCEPTUAL DEVELOPMENT

      1.   Hearing       During the first year, babies start to organize sounds into complex patterns. While habituation studies show that young infants can distinguish all the sounds of every spoken language, they lose this ability; by 6 months of age, babies “screen out” sounds that are not used in their own language. In the second half of the first year, infants focus on the larger speech units crucial for figuring out meaning. Older infants can also detect clauses and phrases in sentences.Between 7 and 9 months, infants have begun to analyze the internal structure of sentences and words

2.    Vision    Infants' vision changes rapidly in the time after birth. By 2 months, infants can discriminate colors across the entire spectrum. By 3 months, infants can focus on objects and discriminate colors about as well as adults can, although thier acuity afor distant sights is not fully developed. By 6 months, their visual acuity is about 20/100.  By 11 months, visual acuity reaches a near-adult level.

• Depth perception is the ability to judge the distance of objects from one another and from ourselves. Research indicates that around the time that infants crawl, most can distinguish deep and shallow surfaces and avoid dangerous-looking drop-offs.    Motion is the first type of depth cue to which infants are sensitive. Binocular depth cues arise because our two eyes have slightly different views of the visual field. Binocular sensitivity emerges between 2 and 3 months. Pictorial depth perception, involving such cues as changes in texture and overlapping objects, develops around the middle of the first year.
  The visual cljff was used in the earliest studies of infants' depth perception.  Investigators have concluded that apprehension of heights is made possible by independent locomotion. Researchers believe that crawling is so important in structuring the infants’ experience of the world, it may promote a new level of brain organization by strengthening certain synaptic connections in the cortex.

• Pattern Perception:  Even newborns prefer to look at patterned as opposed to plain stimuli. They are attracted to look at contrasts in light and dark and if babies can detect a difference in contrast between two patterns, they will prefer the one with more contrast. Once babies can detect all aspects of a pattern, they combine pattern elements and integrate them into a unified whole. By 4 months, infants can perceive subjective boundaries that are not really present, such as  the picture in a book of an apple half hidden by a cup. By the end of the first year, a suggestive image is all that is needed for babies to recognize a familiar form.

• Object Perception  To accurately perceive objects, we must translate changing retinal images into a single representation. Size constancy and shape constancy are the perceptions that an object’s size and shape stay the same, despite the changes in retinal images' size and shape. Both of these perceptual capacities appear to be innate and assist babies in detecting a coherent world of objects.

• Perception of Object Unity ('Figure' as opposed to 'background') At first, babies rely heavily on motion and spatial arrangement to identify objects. Then, as babies visually track moving objects, they pick up additional information about an object’s boundaries, such as its distance from their eye, shape, and color. As infants become familiar with many types of objects they rely more on shape, color, and texture and less on motion to identify objects as separate figures or units.

• Perception of the Human Face: A baby’s tendency to search for structure in a patterned stimulus is quickly applied to face perception.By 3 months, infants can discriminate between the photos of two moderately similar strangers. They can also recognize their mother’s face in a photo. Perception of the human face supports infants’ earliest social relationships.

• Intermodal Perception:  Intermodal perception combines information from more than one modality, or sensory system. Recent evidence indicates that babies perceive the world in an intermodal fashion from the beginning. For example, newborn behaviors suggest that they expect sight, sound, and touch to go together.

 H.  LEARNING CAPACITIES   Learning refers to changes in behavior as the result of experience. Learning is seen as the result of a number of processes:

• Classical Conditioning: Innate reflexes allow classical conditioning in young infants. First, an unconditioned stimulus (UCS) produces a reflexive, or unconditioned response (UCR).  A neutral stimulus, which does not lead to the reflexive response, is presented at the same time as or just before the UCS.  The neutral stimulus, now called a conditioned stimulus (CS), produces the reflex, now called a conditioned response (CR).
  Extinction is a decline in the CR as a result of presenting the CS enough times without the UCS. For a baby to learn easily, the association between a UCS and a CS must have survival value, such as associating the sound or smell of the mother with the comfort and nutrition of being fed.

• Operant Conditioning: Operant conditioning is a form of learning in which a spontaneous behavior is followed by a consequent stimulus that changes the probability that the behavior will occur again. A reinforcer is a stimulus that increases the occurrence of a response. The removal of a desirable stimulus or the presenting of an unpleasant one to decrease the occurrence of a response is called punishment. Operant conditioning soon modifies parents’ and babies’ reactions to each other, as the infant learns how to signal the parents and the parents learn how to respond. Operant conditioning allows researchers to determine what stimuli babies perceive and which ones they prefer. When infants’ environments are so disorganized that their behavior does not lead to predictable outcomes, serious developmental difficulties can result.

• Habituation and Dishabituation: Habituation refers to a gradual reduction in the strength of a response due to repetitive stimulation. Dishabituation is an increase in responsiveness after a new stimulus appears. Habituation and dishabituation enable us to focus on those aspects of the environment we know least about, making learning more efficient. The habituation—dishabituation sequence provides researchers with a marvelous window into early mental development.

• Imitation is  learning by copying the behavior of another person. Research indicates newborns can imitate adult facial expressions and get to know people by matching behavioral states with them. some investigators regard the capacity for imitation as little more than an automatic response; however, newborns imitate diverse facial expressions and head movements with effort and determination. In addition, imitation does not decline as reflexes do. However limited at birth, imitation is a powerful means of learning.

Chapter 6: Cognitive Development 

Piaget's Theory of cognitive development:
Review Piaget's concept of schemes ( organized ways of making sense of experience): adaptation, in which schemes are constructed through direct interaction with the world,  assimilation, in which new material is interpreted by existing schemes, accommodation, in which existing schemes have to be changed or new ones created to account for new experiences that do not fit previous schemes. He proposed that in time of gradual change, equilibrium exists in which assimilation is used more than accommodation, but during times of rapid change, disequilibrium pushes the infant or child to use accommodation until equilibrium is reestablished.  At higher levels of development, schemes are organized into interconnected cognitive systems that can be applied to the environment.

Piaget noted that infants learn with their whole bodies, through movement and sensation, in the first part of their lives. He called this the 'sensorimotor' stage, and broke it down into six substages.  KNOW THEM and be able to give examples of each..

Recent research and newly developed techniques show that infants actually know more than Piaget was able to observe, as their ability to demonstrate what they know is limited by their level of physical skills and development. Some researchers even believe that infants' cognitive skills are based on innate knowledge (the nativist point of view). 

We did an exercise demonstrating the substages of Piaget's Sensorimotor stage of development

Information Processing Theory has a very different theory of infant learning, one which is not based on a theory of stages of development, but rather, that infant learning and adult learning are similar processes, although adults are much better at it. They see infants and adults as having 1) sensory memories, 2) short term memories and 3) long term memories, and that the difference between infant and adult cognition besides the increase in capacity of each of these kinds of memory, is the sophistication and control the adult can bring to bear in using these levels of memory. Some of the techniques include controlling attention, categorizing similar memories, earning mnemonic tricks and techniques, and learning to evaluate techniques that work best and those that are not as efficient.

Vygotsky, a Russian researcher in the first half of the last century, felt that the social and cultural context of learning was critical in the cognitive development of children. He felt that infants and toddlers learned new cognitive skills in the context of interaction with 'experts' whose behavior and language led them to more complex levels of understanding and skill. He saw language as one of the critical tool in this process. He argued that, unlike Piaget's theory tha children learned best by interacting with objects in their environment, adult guidance, teaching, and support were necessary for the child in tackling skills that were in his 'Zone of Proximal Development' (ZPD), things he could not quite yet do on his own, and that in sensitive interactions with needed support, children not only developed faster and better but also acquired the knowledge of their particular cultural norms, values, and beliefs.

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Individual differences in infants' and toddlers' development............

(hmmm, I'VE BEEN WORKING ON THESE NOTES IN BITS AND PIECES, AND  CAN'T FINISH THIS PART BEFORE THE WEEKEND. I WILL TRY TO GET BACK TO IT IF I CAN ...

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 Language development: 

• Language acquisition is 'overdetermined'; so many factors contribute to the development of the ability to speak that, unless something is severely wrong with the child or the environment, all children eventually learn to speak.  Some theorist even go so far as to propose that the infant's brain is genetically and physiologically structured for language acquisition.  
• From before birth, infant becomes familiar with the sound of the mother's voice, the rhythms of her speech. All infants can perceive all the sounds (the phonemes, the units of sound that make up spoken language) of every language ever spoken and, when vocalizing begins, can make all the sounds spoken in the world, but over the course of the first year, loses this early sensitivity and vocal fluidity and becomes a specialist in his/her native language. This specialization allows the infant to ignore non-meaningful variations in his/her native language.
• Language development mirrors, in some ways, the processes of other cognitive development. The infant goes through a predictable sequence of stages in learning to understand language and to talk.

  The infant's initial sounds , cries, convey three basic meanings; hunger, pain and discomfort. They are attracted to the sound of  human speech and recognize their mother's voice. After the first few months, they begin to express more sounds other than cries; coos, gurgles, squeaks and other non-linguistic sounds. At around 20 weeks, they begin to 'babble' a wide variety of phonemes, producing all the sounds from which languages are constructed, This is not goal-directed, but sounds for the sake of making sounds, repeating the same phonemes over and over, much like the physical primary circular behaviors that Piaget described. (Even deaf babies babble, but at a later time in their development; without the auditory feed-back, babbling has no built-in 'consequences' or reinforcement.) By 6 months, they are producing more elaborate 'schemas' of phonemes, including all the vowel sounds and many if not most of the consonants. Receptive language comes before spoken words; voluntary speech involves sophisticated control/coordination over the vocal cords, breathing and  motions of the mouth. At 12 months, infants have the rhythm and intonations of their native language down, and specific sounds begin to be associated with emotions, events, actions and things. They indicate their understanding of many aspects of language (words, tone, rhythm, etc) and deaf infants with parents who speak sign can already 'say' their first words or meaningful gestures. The first spoken 'words', or meaningful combinations of phonemes, appear. These first words may not be exact replicas of the adult words, but they are specific sounds,  understandable approximations, that have semantic meanings; that is, they are clearly associated with concrete events and things. (Names of things and expressions of emotions usually come before verbs, and always before prepositions and adjectives, pronouns, etc.) Words then begin to appear in combinations (sentences ) that have a specific order (syntax) that indicates their meaning. (Consider the sentence of a 16 month-old boy confronting his first McDonald's hamburger: "Pickle hiding under meat!",  said with a squeal of delight.  (Syntax: The sentence would take on a completely different meaning if it was said "Hamburger hiding under pickle!", and would have no meaning at all if it was said "Hiding pickle hamburger under!" ) By age 2 most children no longer babble and are able to express fairly complex ideas in at least simple sentences.

Although overdetermined, language doesn't develop in a vacuum; obviously, a responsive and interactive social environment has important effects on this aspect of development. Infant-directed speech simplifies and exaggerates the patterns and sounds of language for the learning infant, facilitating and reinforcing the infants vocalizations and first verbalizations. Ongoing commentary about repeated events, emphasizing the words associated with these events is one aspect of parent speech that enhances the infants' understanding, and the parent's contingent responses to the infant's vocal or verbal attempts reinforces and expands the infants' efforts.