Freud's theory of psychosexual development proposed that personality develops through childhood stages centered around different erogenous zones. Each stage has implications for personality if a child becomes "fixed" or stuck in that stage due to parenting issues. The stages include oral, anal, phallic, latent, and genital stages from birth to adolescence. Bowlby's attachment theory proposed that early relationships with caregivers lead to secure, avoidant, or anxious attachment styles with lasting effects. Piaget's theory of cognitive development described stages from sensorimotor to formal operations where children construct knowledge through schemas and interactions with the environment.