Eysenck is German-born British psychologist who developed a trait theory of personality that identifies the three basic dimensions of personality as neuroticism, extraversion, and psychoticism. His theory of personality focused on two dimensions of higher-order traits, extraversion vs. introversion and emotional stability vs. neuroticism, or emotional instability. Extraverts are commonly known as being loud and outgoing while introverts are often thought of as quiet and reserved.
