Physical Development Flashcards
A newborn’s brain is about ___ of its adult weight at birth, but it grows rapidly and is about of its adult weight by the time a child is two years old.
25%
80%
Most neurons are present at birth and the increase in size is due to _______ (the creation of new synapses), the growth of new dendrites, and myelination, in which the axons become covered in a fatty substance _____ that acts as an insulator and speeds up the transmission of nerve impulses.
synaptogenesis
(myelin)
two to three
synaptic pruning
Synaptogenesis peaks at ______years of age, and synapses that are used most often are subsequently strengthened and become more efficient while those that are unused atrophy and disappear. This loss of synapses is referred to as _________, and it continues through adolescence.
two to three
synaptic pruning
two to three
synaptic pruning
The cerebral cortex is the _______developed area of the brain at birth, and it continues to develop following birth, with the _____(which controls executive cognitive functions) not reaching maturity until the ____________.
Least
prefrontal cortex
late teens or early to mid-20s
Brain weight and volume begin to gradually decrease at around _____years of age as the result of the loss of _____, and this process accelerates after about age ___. With regard to the cortex, the studies indicate that the decrease in size is greatest for the frontal lobes (especially the prefrontal cortex) and the ___________(e.g., Resnick et al., 2003). Research has also found that the brain compensates for some neuron loss by developing new connections between the remaining neurons and +++++++ (the production of new neurons) in _________the and possibly other areas of the brain.
30
Neurons
60
parietal lobes
neurogenesis
hippocampus
Vision is the ______sense at birth but it improves rapidly. At birth, newborns have limited visual acuity and see at about 20 feet what normal adults see at 400 to 600 feet; but, by about _____months of age, their visual acuity is similar to that of normal adults.
least developed
7 or 8
Despite their limited vision, newborns prefer to look at ______stimuli rather than non-patterned stimuli and prefer facial to non-facial images. By _____months of age, they prefer to look at the faces of their mothers and other caregivers to the faces of strangers.
Patterned
one to two
Depth perception relies on three types of depth information:
Kinetic (motion cues)
Binoculur (stereoscopic cues)
Pictorial (static-monocular cues)
Beginning as early as ________of age, infants rely on _____(motion) cues, which are based on the movement of objects. Between two and three months of age, they begin using ________(stereoscopic) cues, which are derived from the integration of images received by each eye. Then, by about _______months of age, babies begin using ______(static-monocular) cues, which can be perceived with only ___ eye, create the impression of depth, and include size, texture gradients, shadows, and linear perspective.
3 or 4 weeks
kinetic
binocular
5-6
Pictorial (static-monocular)
one
______________are the first senses to show age-related declines in adulthood. By about ___ years of age, many adults begin to experience _______, which is due to a hardening of the lens of the eye, which makes it difficult to focus on nearby objects. Other changes that occur in middle adulthood or later include decreased sensitivity to low levels of illumination, slower dark adaptation, increased sensitivity to glare, reduced ability to discriminate between colors, and decreased depth perception.
Vision and hearing
40
presbyopia
Immediately after birth, newborns are somewhat ___sensitive than adults to sound, especially high-frequency sounds, but their sensitivity to high-frequency sounds develops quickly and comes close to adult levels by _______of age. Within a few days after birth, infants prefer the voice of their _____to the voice of a stranger and other sounds. They also exhibit auditory (sound) localization and _______turn their heads toward the source of sounds, but this ability decreases when infants are between two and four months of age. It then re-emerges and becomes more deliberate and precise and ______to nearly adult levels by about 12 months of age (Clifton, 1992).
Less
six months
mothers
reflexively
improves
Hearing starts to decline for most adults at about ___years of age, beginning with decreased sensitivity to __________(presbycusis) that makes it difficult to understand women’s and young children’s voices as well as fricative consonants (e.g., f, s, t) , which are ________than vowels and other consonants, and ____________such as the beeping of a microwave, the buzzing of a clothes dryer, and the chirping of birds.
40
high-frequency sounds
softer and higher-pitched
non-human sounds
The effects of presbycusis are exacerbated in the presence of background noise. There’s evidence that the _________of age-related hearing loss is related to the risk for developing Alzheimer’s disease and other neurocognitive disorders (Thomson et al., 2017)
severity
Touch is the first sense to develop in utero, and newborns have a __________sense of touch at birth. For example, they respond to a touch to their cheeks by turning their heads in the direction of the touch. They’re also sensitive to____, and the research has shown that newborn male infants cry intensely during circumcision at three days of age when they’re not given an anesthetic (Gunnar, Malone, & Fisch, 1987).
well-developed
pain
There’s also evidence that early exposure to painful experiences affects future responses to pain. Taddio, Katz, Ilersich, and Koren (1997) found that newborns who were not given topical anesthesia during circumcision responded more intensely than those who were given an anesthetic when they received routine vaccinations four to six months later. Note, however, that subsequent research found that the later response to pain differs for full-term and preterm infants: In summary, Early exposure to pain _______later responsivity for full-term infants but ______later responsivity for preterm infants (Taddio & Katz, 2005).
Heightens
dampens
