chapter 4

Chapter 4 Study Guide

Breast Feeding and Infant Growth

• Breastfeeding is important for infant growth because it provides improved nutrition, which is crucial for healthy development. It enhances immunity, offering protection against infections and diseases, and supports overall healthy growth and weight gain in infants.

Neural Development

Neurogenesis

Neurogenesis is the process through which new neurons are formed in the brain. This process primarily occurs during prenatal development but continues to a lesser extent throughout life, particularly in regions such as the hippocampus, which is associated with memory and learning. Factors that influence neurogenesis include genetic programming, environmental factors, and physical exercise.

Synaptogenesis

Synaptogenesis refers to the formation of synapses between neurons, allowing for communication across the nervous system. This process is critical for the development of neural networks and occurs rapidly during early brain development as well as in certain areas of the brain throughout life. The creation of synapses is influenced by experiences, such as learning and sensory stimulation. During synaptogenesis, excess synapses are often initially formed, which are later pruned during development to enhance the efficiency of neural communication.

Myelination

Myelination is the process of forming a myelin sheath around nerve fibers, which acts as an insulating layer. This insulation boosts the speed and efficiency of electrical communication between neurons. Myelination begins in the fetal stage and continues into young adulthood, affecting areas of the brain associated with motor and cognitive functions. The development of myelin is influenced not just by genetic factors, but also by environmental factors such as nutrition and sensory experiences.

Experience-Dependent and Experience-Expectant Brain

Experience-Dependent Brain Development: This refers to the adaptive changes in the brain that occur as a result of individual experiences. Unlike experience-expectant processes, which follow a more universal timeline, experience-dependent development is highly variable and shaped by personal interactions and encounters that an individual has throughout life. This means that the neural pathways and connections formed depend heavily on the unique environment, learning opportunities, and contexts an individual is exposed to. For example, a child who engages in diverse learning activities, such as music, art, or outdoor exploration, will develop different neural pathways compared to a child who has less varied experiences. This type of brain development emphasizes the plasticity of the brain and the significance of personal experiences in shaping cognitive and emotional outcomes.

Experience-Expectant Brain Development: In contrast, experience-expectant development occurs at specific stages of development during which the brain is prepared to be shaped by expected environmental experiences common to all humans, regardless of culture or individual identity. This includes foundational experiences crucial for typical brain development, such as visual input, auditory input, and social interactions during critical periods of growth. For instance, infants have a biologically predisposed readiness to recognize faces and human voices, which are essential for social bonding and communication. These experiences must occur within a certain timeframe, as the brain's organization relies on these universal experiences to form vital neural circuits. Failure to receive such experiences may impair brain development, highlighting the importance of early exposure to these stimuli for cognitive and social skills.

In summary, both experience-dependent and experience-expectant processes play essential roles in the growth and functionality of the brain, yet they operate under different mechanisms and timelines, with one being influenced by individual variation and the other by common, species-wide needs.

Habituation and Dishabituation Paradigm

• Habituation: reduced response to repeated stimuli.

• Dishabituation: renewed response to novel stimuli.

• Visual Preference Technique: assesses infants' stimulus preferences based on looking time.

Reflexes

• Rooting Reflex: This reflex is crucial for newborns as it helps them find food. When an infant's cheek is touched, they will turn their head towards the stimulus, opening their mouth in search of a nipple or bottle. This instinctual behavior supports breastfeeding and is typically observed from birth to about 4 months of age.

• Sucking Reflex: This reflex enables infants to suck on objects placed in their mouths. It's essential for feeding, allowing them to draw milk from the breast or bottle. The sucking reflex instinctively develops as soon as the infant is born and usually persists throughout the first year as they explore different textures and objects.

• Moro Reflex: Also known as the startle reflex, the Moro reflex occurs when an infant feels a sudden loss of support or hears a loud noise. The infant responds by spreading their arms outward and then quickly retracting them, often accompanied by crying. This reflex can be seen from birth up to about 6 months of age and plays a role in the infant's ability to adapt to sudden changes in their environment.

Vision

• Infants exhibit a preference for high-contrast patterns and human faces within the early months of life. This attraction to faces is vital for social development and recognition.

• By 3 months, infants begin developing color perception, being able to distinguish between different colors. Furthermore, visual acuity improves considerably during the first year as the structures of the eye mature and visual processing develops, allowing better clarity and focus on objects.

Audition

• Newborns are born with a heightened sensitivity to phonemes, or distinct sounds, which aids in language acquisition. They can detect phonetic contrasts, allowing them to differentiate between sounds, a key step in understanding speech patterns.

• Infants can categorize speech sounds, which contributes to their ability to learn language by recognizing familiar sounds and syllables, even before they can produce meaningful speech themselves.

Theories of Temperament

• Thomas & Chess: Categorized children into three primary temperament styles:

  • Easy: Generally adaptable, regular in routine, and positive in mood.

  • Difficult: Characterized by intense reactions, irregular routines, and a propensity for negative moods.

  • Slow to Warm Up: These children tend to be more reserved and need time to adjust to new experiences.

• Rothbart: Proposed a model focusing on characteristics that encompass three dimensions:

  • Surgency: Involves the presence of high energy levels, sociability, and positive emotions.

  • Negative Affect: Reflects the extent to which a child displays distress and irritability.

  • Self-Regulation: Refers to the ability to manage one’s emotions and behaviors in response to situations.

Sudden Infant Death Syndrome (SIDS)

• Several factors have been associated with an increased risk of SIDS, including stomach sleeping, being born prematurely, exposure to smoke, and sleeping on soft bedding. Understanding these risks is crucial for the safety and wellbeing of infants.

• To promote safe sleep practices and reduce the risk of SIDS, caregivers are advised to place infants on their backs to sleep, provide a firm sleep surface, and ensure that the sleep environment is free from soft items such as pillows or blankets. Early education on these practices is vital in protecting infants during sleep.