What is Proximodistal trend of body growth?

Explain what is meant by the cephalocaudal trend in physical development and provide an example that illustrates this trend. The cephalocaudal trend is the pattern of physical development slowly beginning at the head and moving quicker toward the tail. An example that illustrates this trend is the changes in body proportion relative to the head. In infancy, the head is equally as large as the rest of the body, however, as one ages, the hips eventually become the halfway mark. 2. Explain what is meant by the proximodistal trend in physical development and provide an example that illustrates this trend. The proximodistal trend is the pattern of physical development slowly beginning with the internal organs and eventually working quickly outwards toward the extremities. An example that illustrates this trend is the awkwardness of teens using their arms and legs. It is at this age that such extremities are in their prime time of development and because they are growing so quickly, teens have yet to adjust to this added growth. 3. Describe the sex differences in skeletal ossification that are present at birth, and compare these to sex differences that are present at age 12. Skeletal ossification is the process whereby soft spots of the skeleton and skull fill with minerals and harden. This skeletal development, however, varies at birth and at age 12 between boys and girls. As a general trend, girls mature faster than boys and thus have an older skeletal age. At birth, girls

The physical bodies of infants and toddlers show common growth trends and these trends relate to motor development. There are two important trends: cephalocaudal and proximodistal. The cephalocaudal trend acknowledges a top-down growth trend. For example, infants may use their upper limbs before their lower limbs. The proximodistal trend, on the other hand, acknowledges growth from the center of the body outwards. For example, infants use their arms before they can use their fingers effectively.

Figure \(\PageIndex{1}\): Infant using both feet to interact with a book. . ([1])

Resources on infant and toddler development sometimes mistakenly reference cephalocaudal and proximodistal trends as principles (i.e., Gonzalez-Mena, 2014). The reason they are trends and not principles is that they only describe what typically happens (a trend) as not all infants show motor development that exactly follows these trends. For example, research has shown that some infants will reach for and interact with objects using their feet before they are able to do so with their hands (Galloway & Thelen, 2004; Heathcock & Galloway, 2009), which does not follow the cephalocaudal trend. Figure# is a picture of an infant using both feet to interact with a book while being read to by a caregiver. [2]

[1] Image by Todd LaMarr is licensed under CC by NC 4.0.

[2] “Cephalocaudal trend” from Wikipedia is licensed under CC by SA 4.0.

Psychology 213: unit 4 -- Physical Development in Infancy and Toddlerhood
(9-13-10)

Changes in body size and muscle-fat makeup

Physical growth is very rapid during the first 24 months of postnatal live

"baby fat" rises with a peak at about 9 months; this helps the infant maintain a constant body temperature

Toddlers begin to be more slender; this trend continues into middle childhood

Individual and group differences

Girls, in infancy, tend to be shorter and lighter, with a higher fat to muscle ratio than boys

There are significant individual and group differences in size and rate of physical growth

A good estimate of a child's physical maturity is the skeletal age, a measure of bone development; girls tend to be ahead of boys during the developmental years and reach their fully body size several years earlier

Developmental treads

cephalocaudal trend -- a pattern of growth occurs from the head downward through the body, the head grows more rapidly than the lower part of the body

proximodistal trend -- a pattern of growth occurs from the center of the body outwards, for instance the arms and legs grow faster than the hands and feet

The central nervous system

The brain at birth has billions of neurons -- nerve cells that store and transmit information

Between the neurons are tiny gaps called synapses

Neurons influence each other through the release of chemicals called neurotransmitters that cross the synapse and stimulate receptor sites on the next cell.

Active neurons establish more synapses with other cells; inactive neurons lose their connections, a process called synaptic pruning

About half of the volume of our brain is made up of glial cells which support the neurons and provide myelination, the coating of neural fibers with myelin, an insulating fatty sheath that improves the speed and efficiency of the neuron's signaling of other cells

Cerebral Cortex

largest, most complex, structure in human brain, and last brain structure to stop growing

different regions of the cerebral cortex has associated functions

anatomy of behavior

the Frontal Lobes are the region with the most extended period of development and is responsible for thought, inhibition of impulses, sustained attention, integration of information, planning and analysis of actions, and the functional use of memory

Sensitive periods in brain development

stimulation of the brain is vital during periods of rapid growth

Changing state of arousal

the organization of sleep and wakefulness changes between birth and age 2

Influences on Early Physical Growth

biological: heredity, nutrition, malnutrition

emotional: parental/caretaker love is critical for human growth and development

nonorganic failure to thrive

modification of response to stimuli with repeated presentations

habituation & sensitization

Classical (or respondent or Pavlovian) conditioning

unconditioned stimuli (innate)

unconditioned responses (reflexes)

conditioned stimuli (learned)

conditioned responses (learned)

Operant (or instrumental or reward) conditioning (or learning)

reinforcement

extinction

discrimination

shaping (successive approximations)

Imitation (or modeling or observational learning) as a form of learning

mirror neurons