420 Part V Biological/Evolutionary Theories
N (Eysenck & Eysenck, 1976). Like extraversion and neuroticism, P is a bipolar factor,
with psychoticism on one pole and superego on the other. High P scorers are often
egocentric, cold, nonconforming, impulsive, hostile, aggressive, suspicious, psycho-
pathic, and antisocial. People low on psychoticism (in the direction of superego func-
tion) tend to be altruistic, highly socialized, empathic, caring, cooperative, conforming,
and conventional (S. Eysenck, 1997).
Earlier, we saw that Eysenck accepted the diathesis-stress model for people
high on the neuroticism scale; that is, stress and high N scores combine to elevate
people’s vulnerability to psychological disorders. This model also suggests that peo-
ple who score high on psychoticism and who are also experiencing levels of stress
have an increased chance of developing a psychotic disorder. Eysenck (1994a)
hypothesized that people high on psychoticism have a high “predisposition to suc-
cumb to stress and develop a psychotic illness” (p. 20). This diathesis-stress model
suggests that high P scorers are genetically more vulnerable to stress than are low P
scorers. During periods of little stress, high P scorers may function normally, but when
high psychoticism interacts with high levels of stress, people become vulnerable to
psychotic disorders. By contrast, people with low P scores are not necessarily vulner-
able to stress-related psychoses and will resist a psychotic break even in periods of
extreme stress. According to Eysenck (1994a, 1994b), the higher the psychoticism
score, the lower the level of stress necessary to precipitate a psychotic reaction.
Psychoticism/superego (P) is independent of both E and N. Figure 14.4
shows each of the three factors at right angles with the other two. (Because three-
dimensional space cannot be faithfully produced on a two-dimensional plane, the
reader is asked to look at Figure 14.4 as if the solid lines represent the corner of
a room where two walls meet the floor. Each line can then be seen as perpendicularNeuroticismStabilityExtraversionSuperegoPsychoticismIntroversionFFIGURE 14.4 Three-dimensional scheme depicting one individual’s scores on each
of Eysenck’s major dimensions of personality.