Development is the pattern of progressive, orderly, and predictable changes that begin at conception and continue throughout life. It involves both growth (gains) and decline (decay/loss), as observed in old age.
The study of human development is guided by several core assumptions:
Human development is shaped by the continuous interaction of heredity (nature) and environment (nurture).
According to Sandra Scarr, parents provide environments that match their own genetic predispositions, and children also actively select niches in their environment that correspond to their genotypes (e.g., an athletically inclined child seeking out sports environments).
Development does not occur in a vacuum; it is deeply embedded in socio-cultural environments.
Urie Bronfenbrenner's ecological systems theory views development as influenced by five nested environmental systems:
Durganand Sinha proposed an ecological model for the Indian context, consisting of two concentric layers:
The period from conception to birth, lasting approximately 40 weeks. It is highly vulnerable to environmental hazards called Teratogens (drugs, infections, radiation, and pollution) which can cause developmental abnormalities or death.
The first two years of life, characterized by rapid brain growth, motor development, and sensory maturation.
| Reflex | Description | Developmental Course |
|---|---|---|
| Rooting | Turning head and opening mouth when cheek is touched | Disappears between 3 and 6 months |
| Moro | Arching back and throwing arms out in response to loud noise | Disappears in 6 to 7 months |
| Grasp | Fingers closing around an object pressed into the palm | Disappears in 3 to 4 months; replaced by voluntary grasping |
| Babinski | Toes fanning out and curling when the sole of the foot is stroked | Disappears in 8 to 12 months |
Infants are in the Sensorimotor Stage (0-2 years). They explore the world through sensory experiences and motor actions. A key milestone is Object Permanence—the understanding that objects continue to exist even when they cannot be seen, heard, or touched.
Infants form a deep emotional bond with caregivers, known as Attachment. Erik Erikson emphasized that the first year of life is critical for establishing Trust vs. Mistrust based on sensitive caregiving.
Case/Experiment Title: Harlow and Harlow's Surrogate Mother Study (1962)
Background/Subject: Infant rhesus monkeys separated from their biological mothers at birth.
Method/Procedure: Monkeys were placed in cages with two surrogate mothers: one made of bare wire that provided milk, and another covered in soft cloth that provided no food.
Observations/Results: The infant monkeys spent significantly more time clinging to the cloth mother, running to her for comfort when frightened, and only visiting the wire mother to feed.
Psychological Inference: Tactile contact-comfort is a more critical factor in forming attachment bonds than the simple provision of nourishment.
Childhood is marked by physical growth, motor refinement, and expanding social horizons.
The transitional period between childhood and adulthood, initiated by Puberty.
According to Erikson, the primary developmental task of adolescence is resolving Identity vs. Identity Confusion to establish a coherent sense of self.