{"id":245,"date":"2014-09-25T21:35:05","date_gmt":"2014-09-25T21:35:05","guid":{"rendered":"https:\/\/courses.candelalearning.com\/lifespandevelopment1x1\/?post_type=chapter&p=245"},"modified":"2016-03-16T18:27:30","modified_gmt":"2016-03-16T18:27:30","slug":"physical-development","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/suny-lifespandevelopment2\/chapter\/physical-development\/","title":{"raw":"Physical Development","rendered":"Physical Development"},"content":{"raw":"

Overall Physical Growth<\/h2>\r\nThe average newborn in the United States weighs about 7.5 pounds and is about 20 inches in length.\u00a0For the first few days of life, infants typically lose about 5 percent of their body weight as they eliminate waste and get used to feeding.\u00a0This often goes unnoticed by most parents, but can be cause for concern for those who have a smaller infant.\u00a0This weight loss is temporary, however, and is followed by a rapid period of growth.\u00a0By the time an infant is 4 months old, it usually doubles in weight and by one year has tripled it birth weight.\u00a0By age 2, the weight has quadrupled.\u00a0The average length at one year is about 26-32 inches.\r\n

Body Proportions<\/strong><\/h3>\r\nAnother dramatic physical change that takes place in the first several years of life is the change in body proportions.\u00a0The head initially makes up about 50 percent of our entire length when we are developing in the womb.\u00a0At birth, the head makes up about 25 percent of our length (think about how much of your length would be head if the proportions were still the same!).\u00a0By age 25 it comprises about 20 percent our length.\u00a0Imagine now how difficult it must be to raise one\u2019s head during the first year of life!\u00a0And indeed, if you have ever seen a 2 to 4 month old infant lying on the stomach trying to raise the head, you know how much of a challenge this is.\r\n

The Brain in the First Two Years<\/h2>\r\nSome of the most dramatic physical change that occurs during this period is in the brain.\u00a0At birth, the brain is about 25 percent its adult weight and this is not true for any other part of the body.\u00a0By age 2, it is at 75 percent its adult weight, at 95 percent by age 6 and at 100 percent by age 7 years.\r\n\r\nWhile most of the brain\u2019s 100 to 200 billion neurons are present at birth, they are not fully mature and during the next several years dendrites or connections between neurons will undergo a period of transient exuberance or temporary dramatic growth.\u00a0There is a proliferation of these dendrites during the first two years so that by age 2, a single neuron might have thousands of dendrites.\u00a0After this dramatic increase, the neural pathways that are not used will be eliminated thereby making those that are used much stronger.\u00a0This activity is occurring primarily in the cortex or the thin outer covering of the brain involved in voluntary activity and thinking.\u00a0The prefrontal cortex that is located behind our forehead continues to grow and mature throughout childhood and experiences an addition growth spurt during adolescence.\u00a0It is the last part of the brain to mature and will eventually comprise 85 percent of the brain\u2019s weight.\u00a0Experience will shape which of these connections are maintained and which of these are lost.\u00a0Ultimately, about 40 percent of these connections will be lost (Webb, Monk, and Nelson, 2001).\u00a0As the prefrontal cortex matures, the child is increasingly able to regulate or control emotions, to plan activity,\u00a0strategize, and have better judgment.\u00a0Of course, this is not fully accomplished in infancy and toddlerhood, but continues throughout childhood and adolescence.\r\n\r\nAnother major change occurring in the central nervous system is the development of myelin, a coating of fatty tissues around the axon of the neuron.\u00a0Myelin helps insulate the nerve cell and speed the rate of transmission of impulses from one cell to another.\u00a0This enhances the building of neural pathways and improves coordination and control of movement and thought processes.\u00a0The development of myelin continues into adolescence but is most dramatic during the first several years of life.\r\n

From Reflexes to Voluntary Movements<\/h2>\r\nInfants are equipped with a number of reflexes which are involuntary movements in response to stimulation.\u00a0These include the sucking reflex (infants suck on objects that touch their lips automatically), the rooting reflex, which involves turning toward any object that touches the cheek, the palmar grasp (the infant will tightly grasp any object placed in its palm), and the dancing reflex evidence when the infant is held in a standing position and moves its feet up and down alternately as if dancing.\u00a0These movements occur automatically and are signals that the infant is functioning well neurologically. Within the first several weeks of life these reflexes are replaced with voluntary movements or motor skills.\r\n

Gross Motor Skills<\/strong><\/h3>\r\nThese voluntary movements involve the use of large muscle groups and are typically large movements of the arms, legs, head, and torso.\u00a0These skills begin to develop first.\u00a0Examples include moving to bring the chin up when lying on the stomach, moving the chest up, rocking back and forth on hands and knees.\u00a0But it also includes exploring an object with one\u2019s feet as many babies do as early as 8 weeks of age if seated in a carrier or other devise that frees the hips.\u00a0This may be easier than reaching for an object with the hands, which requires much more practice (Berk, 2007).\u00a0And sometimes an infant will try to move toward an object while crawling and surprisingly move backward because of the greater amount of strength in the arms than in the legs!\r\n

Fine Motor Skills<\/strong><\/h3>\r\nFine motor skills are more exact movements of the hands and fingers and include the ability to reach and grasp an object.\u00a0Newborns cannot grasp objects voluntarily but do wave their arms toward objects of interest.\u00a0At about 4 months of age, the infant is able to reach for an object, first with both arms and within a few weeks, with only one arm.\u00a0Grasping an object involves the use of the fingers and palm, but no thumbs.\u00a0Stop reading for a moment and try to grasp an object using these fingers and the palm.\u00a0How does that feel?\u00a0How much control do you have over the object?\u00a0If it is a pen or pencil, are you able to write with it?\u00a0Can you draw a picture?\u00a0The answer is probably not.\u00a0Use of the thumb comes at about 9 months of age when the infant is able to grasp an object using the forefinger and thumb.\u00a0This ability greatly enhances the ability to control and manipulate an object and infants take great delight in this newfound ability.\u00a0They may spend hours picking up small objects from the floor and placing them in\u00a0containers.\u00a0By 9 months, an infant can also watch a moving object, reach for it as it approaches and grab it.\u00a0This is quite a complicated set of actions if we remember how difficult this would have been just a few months earlier.\r\n

Sensory Development<\/h2>\r\n

Vision<\/strong><\/h3>\r\nThe womb is a dark environment void of visual stimulation.\u00a0Consequently, vision is the most poorly developed sense at birth.\u00a0Newborns typically cannot see further than 8 to 16 inches away from their faces, have difficulty keeping a moving object within their gaze, and can detect contrast more than color differences. If you have ever seen a newborn struggle to see, you can appreciate the cognitive efforts being made to take in visual stimulation and build those neural pathways between the eye and the brain.\u00a0When you glance at a person, where do you look?\u00a0Chances are you look into their eyes.\u00a0If so why?\u00a0It is probably because there is more information there than in other parts of the face.\u00a0Newborns do not scan objects this way; rather, they tend to look at the chin another less detailed part of the face.\u00a0However, by 2 or 3 months, they will seek more detail when exploring an object visually and begin showing preferences for unusual images over familiar ones and for patterns over solids and faces over patterns and three-dimensional objects over flat images.\u00a0Newborns have difficulty distinguishing between colors, but within a few months are able to discrimination between colors as well as do adults.\u00a0Infants can also sense depth as binocular vision develops at about 2 months of age.\u00a0By 6 months, the infant can perceive depth perception in pictures as well (Sen, Yonas, and Knill, 2001).\u00a0Infants who have experience crawling and exploring will pay greater attention to visual cues of depth and modify their actions accordingly (Berk, 2007).\r\n

Hearing<\/strong><\/h3>\r\nThe infant\u2019s sense of hearing is very keen at birth.\u00a0If you remember, this ability to hear is evidenced as soon as the 5th\u00a0month of prenatal development.\u00a0In fact, an infant can distinguish between very similar sounds as early as one month after birth and can distinguish between a familiar and non-familiar voice even earlier.\u00a0Some of this ability will be lost by 7 or 8 months as a child becomes familiar with the sounds of a particular language and less sensitive to sounds that are part of an unfamiliar language.\r\n

Other senses<\/strong><\/h3>\r\nNewborns can distinguish between sour, bitter, sweet, and salty flavors and show a preference for sweet flavors. They are sensitive to touch and can distinguish between their mother's scent and that of others.","rendered":"

Overall Physical Growth<\/h2>\n

The average newborn in the United States weighs about 7.5 pounds and is about 20 inches in length.\u00a0For the first few days of life, infants typically lose about 5 percent of their body weight as they eliminate waste and get used to feeding.\u00a0This often goes unnoticed by most parents, but can be cause for concern for those who have a smaller infant.\u00a0This weight loss is temporary, however, and is followed by a rapid period of growth.\u00a0By the time an infant is 4 months old, it usually doubles in weight and by one year has tripled it birth weight.\u00a0By age 2, the weight has quadrupled.\u00a0The average length at one year is about 26-32 inches.<\/p>\n

Body Proportions<\/strong><\/h3>\n

Another dramatic physical change that takes place in the first several years of life is the change in body proportions.\u00a0The head initially makes up about 50 percent of our entire length when we are developing in the womb.\u00a0At birth, the head makes up about 25 percent of our length (think about how much of your length would be head if the proportions were still the same!).\u00a0By age 25 it comprises about 20 percent our length.\u00a0Imagine now how difficult it must be to raise one\u2019s head during the first year of life!\u00a0And indeed, if you have ever seen a 2 to 4 month old infant lying on the stomach trying to raise the head, you know how much of a challenge this is.<\/p>\n

The Brain in the First Two Years<\/h2>\n

Some of the most dramatic physical change that occurs during this period is in the brain.\u00a0At birth, the brain is about 25 percent its adult weight and this is not true for any other part of the body.\u00a0By age 2, it is at 75 percent its adult weight, at 95 percent by age 6 and at 100 percent by age 7 years.<\/p>\n

While most of the brain\u2019s 100 to 200 billion neurons are present at birth, they are not fully mature and during the next several years dendrites or connections between neurons will undergo a period of transient exuberance or temporary dramatic growth.\u00a0There is a proliferation of these dendrites during the first two years so that by age 2, a single neuron might have thousands of dendrites.\u00a0After this dramatic increase, the neural pathways that are not used will be eliminated thereby making those that are used much stronger.\u00a0This activity is occurring primarily in the cortex or the thin outer covering of the brain involved in voluntary activity and thinking.\u00a0The prefrontal cortex that is located behind our forehead continues to grow and mature throughout childhood and experiences an addition growth spurt during adolescence.\u00a0It is the last part of the brain to mature and will eventually comprise 85 percent of the brain\u2019s weight.\u00a0Experience will shape which of these connections are maintained and which of these are lost.\u00a0Ultimately, about 40 percent of these connections will be lost (Webb, Monk, and Nelson, 2001).\u00a0As the prefrontal cortex matures, the child is increasingly able to regulate or control emotions, to plan activity,\u00a0strategize, and have better judgment.\u00a0Of course, this is not fully accomplished in infancy and toddlerhood, but continues throughout childhood and adolescence.<\/p>\n

Another major change occurring in the central nervous system is the development of myelin, a coating of fatty tissues around the axon of the neuron.\u00a0Myelin helps insulate the nerve cell and speed the rate of transmission of impulses from one cell to another.\u00a0This enhances the building of neural pathways and improves coordination and control of movement and thought processes.\u00a0The development of myelin continues into adolescence but is most dramatic during the first several years of life.<\/p>\n

From Reflexes to Voluntary Movements<\/h2>\n

Infants are equipped with a number of reflexes which are involuntary movements in response to stimulation.\u00a0These include the sucking reflex (infants suck on objects that touch their lips automatically), the rooting reflex, which involves turning toward any object that touches the cheek, the palmar grasp (the infant will tightly grasp any object placed in its palm), and the dancing reflex evidence when the infant is held in a standing position and moves its feet up and down alternately as if dancing.\u00a0These movements occur automatically and are signals that the infant is functioning well neurologically. Within the first several weeks of life these reflexes are replaced with voluntary movements or motor skills.<\/p>\n

Gross Motor Skills<\/strong><\/h3>\n

These voluntary movements involve the use of large muscle groups and are typically large movements of the arms, legs, head, and torso.\u00a0These skills begin to develop first.\u00a0Examples include moving to bring the chin up when lying on the stomach, moving the chest up, rocking back and forth on hands and knees.\u00a0But it also includes exploring an object with one\u2019s feet as many babies do as early as 8 weeks of age if seated in a carrier or other devise that frees the hips.\u00a0This may be easier than reaching for an object with the hands, which requires much more practice (Berk, 2007).\u00a0And sometimes an infant will try to move toward an object while crawling and surprisingly move backward because of the greater amount of strength in the arms than in the legs!<\/p>\n

Fine Motor Skills<\/strong><\/h3>\n

Fine motor skills are more exact movements of the hands and fingers and include the ability to reach and grasp an object.\u00a0Newborns cannot grasp objects voluntarily but do wave their arms toward objects of interest.\u00a0At about 4 months of age, the infant is able to reach for an object, first with both arms and within a few weeks, with only one arm.\u00a0Grasping an object involves the use of the fingers and palm, but no thumbs.\u00a0Stop reading for a moment and try to grasp an object using these fingers and the palm.\u00a0How does that feel?\u00a0How much control do you have over the object?\u00a0If it is a pen or pencil, are you able to write with it?\u00a0Can you draw a picture?\u00a0The answer is probably not.\u00a0Use of the thumb comes at about 9 months of age when the infant is able to grasp an object using the forefinger and thumb.\u00a0This ability greatly enhances the ability to control and manipulate an object and infants take great delight in this newfound ability.\u00a0They may spend hours picking up small objects from the floor and placing them in\u00a0containers.\u00a0By 9 months, an infant can also watch a moving object, reach for it as it approaches and grab it.\u00a0This is quite a complicated set of actions if we remember how difficult this would have been just a few months earlier.<\/p>\n

Sensory Development<\/h2>\n

Vision<\/strong><\/h3>\n

The womb is a dark environment void of visual stimulation.\u00a0Consequently, vision is the most poorly developed sense at birth.\u00a0Newborns typically cannot see further than 8 to 16 inches away from their faces, have difficulty keeping a moving object within their gaze, and can detect contrast more than color differences. If you have ever seen a newborn struggle to see, you can appreciate the cognitive efforts being made to take in visual stimulation and build those neural pathways between the eye and the brain.\u00a0When you glance at a person, where do you look?\u00a0Chances are you look into their eyes.\u00a0If so why?\u00a0It is probably because there is more information there than in other parts of the face.\u00a0Newborns do not scan objects this way; rather, they tend to look at the chin another less detailed part of the face.\u00a0However, by 2 or 3 months, they will seek more detail when exploring an object visually and begin showing preferences for unusual images over familiar ones and for patterns over solids and faces over patterns and three-dimensional objects over flat images.\u00a0Newborns have difficulty distinguishing between colors, but within a few months are able to discrimination between colors as well as do adults.\u00a0Infants can also sense depth as binocular vision develops at about 2 months of age.\u00a0By 6 months, the infant can perceive depth perception in pictures as well (Sen, Yonas, and Knill, 2001).\u00a0Infants who have experience crawling and exploring will pay greater attention to visual cues of depth and modify their actions accordingly (Berk, 2007).<\/p>\n

Hearing<\/strong><\/h3>\n

The infant\u2019s sense of hearing is very keen at birth.\u00a0If you remember, this ability to hear is evidenced as soon as the 5th\u00a0month of prenatal development.\u00a0In fact, an infant can distinguish between very similar sounds as early as one month after birth and can distinguish between a familiar and non-familiar voice even earlier.\u00a0Some of this ability will be lost by 7 or 8 months as a child becomes familiar with the sounds of a particular language and less sensitive to sounds that are part of an unfamiliar language.<\/p>\n

Other senses<\/strong><\/h3>\n

Newborns can distinguish between sour, bitter, sweet, and salty flavors and show a preference for sweet flavors. They are sensitive to touch and can distinguish between their mother’s scent and that of others.<\/p>\n\n\t\t\t

\n\t\t\t

Candela Citations<\/h3>\n\t\t\t\t\t
\n\t\t\t\t\t\t
\n\t\t\t\t\t\t\t
CC licensed content, Shared previously<\/div>