The 'general to specific' principle in child development describes how infants initially exhibit broad, undifferentiated, and reflexive movements. Over time, these movements become more refined, purposeful, and localized. For example, an infant might initially wave their entire arm to reach for an object, but as they develop, they learn to use their fingers and wrists with precision. This progression is a hallmark of motor development, reflecting the maturation of the nervous system and the acquisition of fine motor control.

Motor development follows a predictable sequence. By age two, toddlers typically achieve independent locomotion (walking) and improved fine motor control, allowing them to manipulate objects. More complex gross motor skills, such as hopping or catching, require greater coordination and balance, which typically develop between ages three and six, rather than at age eight.

At the moment of conception, the fusion of a male sperm and a female egg creates a single, diploid cell known as a zygote. This cell contains the complete set of genetic information required to develop into a new organism. It is the earliest stage of prenatal development, preceding the embryonic and fetal stages.

Maturation refers to the biologically programmed sequence of physical and behavioral changes that occur as an organism grows. While environmental factors and learning play significant roles in development, maturation is primarily driven by genetic blueprints. It ensures that developmental milestones, such as walking or reaching puberty, occur in a predictable order and timeframe, reflecting the continuous influence of heredity throughout the lifespan.

This level of moral development is characterized by obedience to authority and avoidance of punishment. Children at this stage prioritize consequences over personal moral principles. They view rules as fixed and absolute, and their behavior is driven by the desire to avoid negative outcomes or physical pain associated with breaking those rules, rather than internalizing societal values.

The term 'developmental' is used in psychology to describe the ongoing, dynamic process of change that occurs throughout the lifespan, particularly during youth. It encompasses physical, cognitive, and socio-emotional maturation. Viewing a young person as 'developmental' acknowledges their inherent capacity for learning, adaptation, and the acquisition of new skills, emphasizing that their current state is not fixed but rather a phase in a continuous journey of growth.

In standard developmental psychology, the stage that follows infancy is childhood. This period is characterized by significant physical, cognitive, and social growth, laying the essential foundation for later stages such as adolescence. Childhood is a broad developmental phase that encompasses the transition from the dependency of infancy to the increased autonomy and complex social interactions of the school-age years.

A child's intellectual development and their walking age are not directly related. Walking milestones are primarily physical and motor-based, while intellectual development encompasses cognitive abilities, language, and abstract learning. While both are developmental milestones, they progress through different biological and environmental mechanisms, meaning that early or late walking is not a reliable predictor of future cognitive intelligence or mental capacity.

The first trimester is the period of organogenesis, where the major organ systems of the fetus are formed. Because this is a time of rapid cell division and differentiation, the fetus is highly vulnerable to external substances, including medications, which can disrupt normal development and lead to congenital malformations.

Diana Baumrind is widely recognized for her research in the 1960s and 1970s, where she identified three main parenting styles: authoritative, authoritarian, and permissive. Her work significantly influenced developmental psychology by linking these styles to specific child outcomes in social and emotional development.