Final answer:
Psychologist Erik Erikson developed the psychosocial theory of development, which includes eight stages from infancy to late adulthood. The theory emphasizes the resolution of conflicts and mastery of tasks at each stage in influencing personality development, highlighting the role of social relationships and interactions.
Step-by-step explanation:
The theory that identified each stage in development as having a crisis and posited that successful or unsuccessful completion affects progression to the next stage was developed by psychologist Erik Erikson. Erikson proposed that personality development is influenced by the resolution of psychosocial crises that occur throughout a person's life. He outlined eight distinct stages in his psychosocial theory of development, which span from infancy to late adulthood.
Erikson's theory emphasized the social nature of our development rather than the sexual nature, as suggested by Freud. His approach was distinctive because he believed that personality continues to change over time and is heavily influenced by social interactions and the successful completion of social tasks, which shape our sense of self or ego identity.
Erikson's Eight Stages of Psychosocial Development
In contrast to Freud's psychosexual stages, Erikson focused on the evolving social relationships that are significant at each stage of personality development. A healthy personality and a sense of competence are developed through the successful completion of the tasks associated with each stage. Erikson's psychosocial theory is a critical framework studied by developmental psychologists who recognize development as a lifelong process impacted by both individual and social factors.