The Life Span Perspective (LSP) assumes:
1. Development is life-long: Development is a continuous process that occurs throughout an individual's life, from birth to death.
2. Biological, cognitive, and socio-emotional processes are interwoven in development: Development involves the integration of biological, cognitive, and socio-emotional processes.
3. Skills and abilities can be improved throughout the life span: Individuals can continue to develop and improve their skills and abilities throughout their lives.
The assumption that "Development is unidirectional" is not a core assumption of the Life Span Perspective. Instead, LSP recognizes that development can involve both gains and losses, and that individuals may experience periods of growth and decline throughout their lives.