Final answer:
The Eysencks proposed a biologically based personality theory with two dimensions: extroversion/introversion and neuroticism/stability. These dimensions explain different personality traits and temperaments, categorized similarly to ancient Greek temperaments, and relate to the sympathetic and parasympathetic nervous system activities.
Step-by-step explanation:
Hans Eysenck's Reticular Activation System Theory (RAS)
Hans and Sybil Eysenck were influential figures in the field of personality psychology. They proposed that personality is primarily governed by biology rather than by experiences. In particular, their theory suggested that there are two main dimensions of personality: extroversion/introversion and neuroticism/stability. Individuals who are high in extroversion tend to be sociable and outgoing, while those who are high in introversion prefer solitude and less social engagement.
On the other hand, the neuroticism/stability dimension refers to emotional stability. Those high in neuroticism are more likely to experience anxiety and have an overactive sympathetic nervous system, making them more susceptible to stress responses. Conversely, people high in stability require more significant stimulation to experience a fight-or-flight reaction and are generally more emotionally steady.
Their model explains how individuals may fall into one of four temperamental categories that are akin to the ancient Greek temperaments: melancholic, choleric, phlegmatic, and sanguine. This categorization links physiological responses to psychological stimuli and general sympathetic and parasympathetic activation.