Here is my definition of influence on the individual:

Any conscious or unconscious modification, of an individual's, perception, thought, belief system, communication, emotions, and actions by the verbal or nonverbal communication, product, or action of another individual or group, whether intentional or not.

(I have deliberately chosen, in order to improve perception, to formulate it precisely instead of using generic terms such as "process" or "interaction").

It is inevitable.

It is partly surmountable as soon as the individual reaches a certain autonomy of thought and is aware of its existence.

The "a priori" quality and effects of an influence are impossible to evaluate and demonstrate.

The sum of experiences that is our life influence us and build us psychically.

 

Please do not plagiarize this definition and cite the source if you wish to use it.