Hans eysenck suggested that two traits are the most important traits of the five-factor model. more recently, jeffrey gray has suggested that these two traits are important because they are related to fundamental reward and avoidance systems in the brain. which two traits of the five-factor model are eysenck and gray referring to, and how do they map onto the reward and avoidance systems?

They refer to extroverts an neurotic individuals.

Extroverts approach rewards while Neurotic individuals avoid punishment

Explanation:

Eysenck's 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.