Infants in the context of "Psychological development"

Developmental psychology is the scientific study of how and why humans grow, change, and adapt across the course of their lives. Originally concerned with infants and children, the field has expanded to include adolescence, adult development, aging, and the entire lifespan. Developmental psychologists aim to explain how thinking, feeling, and behaviors change throughout life. This field examines change across three major dimensions, which are physical development, cognitive development, and social emotional development. Within these three dimensions are a broad range of topics including motor skills, executive functions, moral understanding, language acquisition, social change, personality, emotional development, self-concept, and identity formation.

Developmental psychology explores the influence of both nature and nurture on human development, as well as the processes of change that occur across different contexts over time. Many researchers are interested in the interactions among personal characteristics, the individual's behavior, and environmental factors, including the social context and the built environment. Ongoing debates in regards to developmental psychology include biological essentialism vs. neuroplasticity and stages of development vs. dynamic systems of development. While research in developmental psychology has certain limitations, ongoing studies aim to understand how life stage transitions and biological factors influence human behavior and development.

Haptic communication is nonverbal communication and interaction via the sense of touch. Touch can come in many different forms, some can promote physical and psychological well-being. A warm, loving touch can lead to positive outcomes while a violent touch can ultimately lead to a negative outcome. The sense of touch allows one to experience different sensations such as pleasure, pain, heat, or cold. One of the most significant aspects of touch is the ability to convey and enhance physical intimacy. The sense of touch is the fundamental component of haptic communication for interpersonal relationships. Touch can be categorized in many terms such as positive, playful, control, ritualistic, task-related or unintentional. It can be both sexual (kissing is one example that some perceive as sexual), and platonic (such as hugging or a handshake). Striking, pushing, pulling, pinching, kicking, strangling and hand-to-hand fighting are forms of touch in the context of physical abuse.

Touch is the most sophisticated and intimate of the five senses. Touch or haptics, from the ancient Greek word haptikos, is vital for survival.Touch is the first sense to develop in the fetus. The development of an infant's haptic senses and how it relates to the development of the other senses, such as vision, has been the target of much research. Human babies have been observed to have enormous difficulty surviving if they do not possess a sense of touch, even if they retain sight and hearing. Infants who can perceive through touch, even without sight and hearing, tend to fare much better.

Digestion is the breakdown of large insoluble food compounds into small water-soluble components so that they can be absorbed into the blood plasma. In certain organisms, these smaller substances are absorbed through the small intestine into the blood stream. Digestion is a form of catabolism that is often divided into two processes based on how food is broken down: mechanical and chemical digestion. The term mechanical digestion refers to the physical breakdown of large pieces of food into smaller pieces which can subsequently be accessed by digestive enzymes. Mechanical digestion takes place in the mouth through mastication and in the small intestine through segmentation contractions. In chemical digestion, enzymes break down food into the small compounds that the body can use.

In the human digestive system, food enters the mouth and mechanical digestion of the food starts by the action of mastication (chewing), a form of mechanical digestion, and the wetting contact of saliva. Saliva, a liquid secreted by the salivary glands, contains salivary amylase, an enzyme which starts the digestion of starch in the food. The saliva also contains mucus, which lubricates the food; the electrolyte hydrogencarbonate (HCO₃), which provides the ideal conditions of pH for amylase to work; and other electrolytes (Na, K, Cl). About 30% of starch is hydrolyzed into disaccharide in the oral cavity (mouth). After undergoing mastication and starch digestion, the food will be in the form of a small, round slurry mass called a bolus. It will then travel down the esophagus and into the stomach by the action of peristalsis. Gastric juice in the stomach starts protein digestion. Gastric juice mainly contains hydrochloric acid and pepsin. In infants and toddlers, gastric juice also contains rennin to digest milk proteins. As the first two chemicals may damage the stomach wall, mucus and bicarbonates are secreted by the stomach. They provide a slimy layer that acts as a shield against the damaging effects of chemicals like concentrated hydrochloric acid while also aiding lubrication. Hydrochloric acid provides acidic pH for pepsin. At the same time protein digestion is occurring, mechanical mixing occurs by peristalsis, which is waves of muscular contractions that move along the stomach wall. This allows the mass of food to further mix with the digestive enzymes. Pepsin breaks down proteins into peptides or proteoses, which are further broken down into dipeptides and amino acids by enzymes in the small intestine. Studies suggest that increasing the number of chews per bite increases relevant gut hormones and may decrease self-reported hunger and food intake.

Breast milk (sometimes spelled as breastmilk) or mother's milk is milk produced by the mammary glands in the breasts of women. Breast milk is the primary source of nutrition for newborn infants, comprising fats, proteins, carbohydrates, and a varying composition of minerals and vitamins. Breast milk also contains substances that help protect an infant against infection and inflammation, such as symbiotic bacteria and other microorganisms and immunoglobulin A, whilst also contributing to the healthy development of the infant's immune system and gut microbiome.

Infant formula, also called baby formula, simply formula (American English), formula milk, baby milk, or infant milk (British English), is a manufactured food designed and marketed for feeding babies and infants under 12 months of age, usually prepared for bottle-feeding or cup-feeding from powder (mixed with water) or liquid (with or without additional water). The U.S. Federal Food, Drug, and Cosmetic Act (FFDCA) defines infant formula as "a food which purports to be or is represented for special dietary use solely as a food for infants because it simulates human milk or its suitability as a complete or partial substitute for human milk".

A 2001 World Health Organization (WHO) report found that infant formula prepared per applicable Codex Alimentarius standards was a safe complementary food and a suitable breast milk substitute. In 2003, the WHO and UNICEF published their Global Strategy for Infant and Young Child Feeding, which restated that "processed-food products for ... young children should, when sold or otherwise distributed, meet applicable standards recommended by the Codex Alimentarius Commission", and also warned that "lack of breastfeeding—and especially lack of exclusive breastfeeding during the first half-year of life—are important risk factors for infant and childhood morbidity and mortality".