One of the psychological theories that can be used in literary studies is
human development theory which talks about human lifetime patterns of change.
To be more specific, there is a lifespan of human development by Baltes. It
studies how people grow, change, and stay the same throughout their lives.
According to Baltes, Lindenberger, and Staudinger, the human development can
be described by several principles: multidimensional, multidirectional, plastic,
influenced by multiple contexts, and multidisciplinary (Shakespeare 3-7).
• Multidimensional means that the development entails changes in physical,
cognitive, and socioemotional.
• As the changes are multidimensional, it also happened that the development
study or research is also multidisciplinary, which means that it is across
several studies such as biology, psychology, and sociology.
• Multidirectional means that in the way humans develop, they do not only
gain something but also lose.
• The plastic principle came from plasticity, which means changeable, so
humans can make improvements to support development.
• Furthermore, one of the most important aspects of development is what
influences the development came from where and when the human
development. It contains physical and social environments such as family,
neighbourhood, country, culture, ethnicity, economic issue, etc. (Baltes,
Lindenberger, and Staudinger in Shakespeare 3-7).
As Baltes said above, human development does not escape the social
context, which has been stated by several previous researchers in their theory.