{"id":920,"date":"2024-02-26T22:29:29","date_gmt":"2024-02-27T03:29:29","guid":{"rendered":"https:\/\/opentextbooks.concordia.ca\/psyc200\/chapter\/ages-stages-and-milestones-of-development\/"},"modified":"2025-09-12T16:41:08","modified_gmt":"2025-09-12T20:41:08","slug":"ages-stages-and-milestones-of-development","status":"publish","type":"chapter","link":"https:\/\/opentextbooks.concordia.ca\/psyc205\/chapter\/ages-stages-and-milestones-of-development\/","title":{"raw":"Ages, Stages, and Milestones of Development","rendered":"Ages, Stages, and Milestones of Development"},"content":{"raw":"

Infancy Through Childhood<\/h1>\r\nThe average newborn weighs approximately 7.5 pounds. \u202fAlthough small, a newborn is not completely helpless because\u202ftheir\u202freflexes and sensory capacities help\u202fthem\u202finteract with the environment from the moment of birth. All healthy babies are born with\u202fnewborn reflexes: inborn automatic responses to\u202fspecific\u202fforms of stimulation. Reflexes help the newborn survive until\u202fthey\u2019re\u202fcapable of more complex \u202fbehaviours; these reflexes are crucial to survival. They are present in babies whose brains are developing normally and usually disappear around 4\u20135 months old.\r\n

Let\u2019s\u202fTake a Look\u202fat Some of These Newborn Reflexes<\/h2>\r\nThe rooting reflex<\/strong> is the newborn\u2019s response to anything that touches their cheek; when you stroke a baby\u2019s cheek, they naturally\u202fturn\u202ftheir head in that direction and begin to suck. The sucking reflex<\/strong> is the automatic, unlearned, sucking motions that infants do with their mouths.\u202fYou can observe the grasping reflex<\/strong>\u202fif you put your finger into a newborn\u2019s hand,\u202fthey\u202fautomatically\u202fgrasp\u202fanything that touches their palms.\r\n\r\nThe Moro reflex<\/strong> is the newborn\u2019s response when a baby feels like they are falling. The baby spreads their arms, pulls them back in, and then (usually) cries. How do you think these reflexes promote survival in the first months of life?\r\n\r\nWatch this video, created by the Inter-Tribal Council of Michigan, describing and showing newborn reflexes, to learn more.\r\n\r\nWatch this video: Newborn Reflexes: The Power of Your Newborn (5 minutes)<\/a>\r\n\r\nhttps:\/\/youtu.be\/0vrdkzOnGgo?si=SY84Ik8dZWIx6IVd\r\n

\u201cNewborn Reflexes: The Power of Your Newborn\u201d video by Inter-Tribal Council of Michigan is licensed under the Standard YouTube Licence.<\/p>\r\n\r\n

What Can Young Infants See, Hear, and Smell?<\/h2>\r\nNewborn infants\u2019 sensory abilities are significant, but their senses are not yet fully developed. Many of a newborn\u2019s innate preferences facilitate interaction with caregivers and other humans. Although vision is their least developed sense, newborns already show a preference for faces. Babies who are just a few days old also prefer human voices; they will listen to voices longer than sounds that do not involve speech (Vouloumanos & Werker, 2004). They seem to prefer the voice of the parent in whose womb the baby developed over a stranger\u2019s voice (Mills & Melhuish, 1974). 3-week-old babies were given pacifiers that played a recording of the pregnant parent\u2019s voice and of a stranger\u2019s voice. When the infants heard their parent\u2019s voice, they sucked more strongly at the pacifier (Mills & Melhuish, 1974).\r\n\r\nNewborns also have a strong sense of smell. Newborn babies can distinguish the smell of the parent who was pregnant from that of others. 1-week-old babies who were being breastfed were placed between two gauze pads. One gauze pad was from the bra of a nursing parent who was a stranger, and the other gauze pad was from the bra of the infant\u2019s own nursing parent. More than two-thirds of the week-old babies turned toward the gauze pad with their own nursing parent\u2019s scent (MacFarlane (1978).\r\n

Physical Development<\/h2>\r\nDuring infancy, toddlerhood, and early childhood, the body\u2019s physical development is rapid.\u202fOn average, newborns weigh between 5 and 10 pounds.\u202fBy the age of 2, this weight will have quadrupled, with most 2-year-olds\u202fweighing between 20 and 40 pounds (WHO\u202fMulticentre\u202fGrowth Reference Study Group, 2006).\u202f Growth slows between 4 and 6 years old. During this time children gain 5\u20137 pounds and grow about 2\u20133 inches per year.\r\n\r\n[caption id=\"attachment_919\" align=\"aligncenter\" width=\"350\" class=\"horiz-picture-small-adjustment\"]\"A Figure LD.10. Physical development.<\/strong> Children experience rapid physical changes through infancy and early childhood. Alt. text:<\/strong> A collage of four photographs depicting babies is shown. From left to right they get progressively older. The far left photograph is a bundled up sleeping newborn. To the right is a picture of a toddler. To the right is a child sitting outside. To the far right is a child on a swing set. Source:<\/strong> Image by T\u00fa Nguy\u1ec5n<\/a> from Pixabay<\/a>,\u00a0Image by b13923790<\/a> from Pixabay,<\/a>\u00a0Image by Alisa Dyson<\/a> from Pixabay<\/a> and\u00a0Image by hansdakfamilyministry<\/a> from Pixabay<\/a> are\u00a0used under the Pixabay Content Licence<\/a>.[\/caption]\r\n\r\nThe\u202fnervous system continues to grow and develop\u202fafter\u202fbirth;\u202feach neural pathway forms thousands of new connections during infancy and toddlerhood. This period of rapid neural growth is called blooming<\/strong>. The blooming period of neural growth is then followed by a period of pruning<\/strong>, where neural connections are reduced. It is thought that pruning\u202fallows\u202fthe brain to function more efficiently, allowing for mastery of more complex skills (Hutchinson, 2011). Blooming occurs during the first few years of life, and pruning continues through childhood and into adolescence in various areas of the brain.\r\n\r\nThe size of our brains increases rapidly.\r\n