Complexity theory psychology definition

What is the key concept of complexity?
A key concept of complexity science is universality, which is the idea that many systems in different domains display phenomena with common underlying features that can be described using the same scientific models.
These concepts warrant a new multidisciplinary mathematical/computational framework..
Cognitive complexity can also help individuals analyze situations more accurately by allowing them to see shades of nuance and meaning more clearly.
The core determining factor in the complexity of an individual's cognition is their life experience and education._{Mar 31, 2022}
Primarily a psychoanalytic term, it is found extensively in the works of Carl Jung and Sigmund Freud.
An example of a complex would be as follows: if you had a leg amputated when you were a child, this would influence your life in profound ways, even if you overcame the physical handicap.

What is the key concept of complexity?