fei75766_ch14_435-462.indd 449  02/06/20 01:10 PM
Chapter 14    Eysenck’s Biologically Based Factor Theory449
stress. According toEysenck (1994a, 1994b), thehigher thepsychoticism score, the
lower thelevelofstress necessary toprecipitate apsychotic reaction.
Psychoticism/superego (P)isindependent ofbothEandN.Figure 14.5shows 
eachofthethree factors atrightangles withtheother two.(Because three-dimensional 
space cannot befaithfully produced onatwo-dimensional plane, thereader isasked 
tolookatFigure 14.5asifthesolid linesrepresent thecorner ofaroom where two
walls meet thefloor. Each linecanthenbeseenasperpendicular totheother two.) 
Eysenck’s viewofpersonality, therefore, allows eachperson tobemeasured onthree 
independent factors andresultant scores tobeplotted inspace having three coordi -
nates. Person FinFigure 14.5, forexample, isquite highonsuperego, somewhat high
onextraversion, andnearthemidpoint ontheneuroticism/stability scale. Insimilar 
fashion, scores ofeachperson canbeplotted inthree-dimensional space.
Measuring Personality
Eysenck evolved fourpersonality inventories thatmeasure hissuperfactors. The
first,theMaudsley Personality Inventory, orMPI(Eysenck, 1959), assessed only
EandNandyielded some correlation between these twofactors. Forthisreason, 
Eysenck developed another test,theEysenck Personality Inventory, orEPI.TheEPI
contains alie(L)scale todetect faking, butmore importantly, itmeasures extraver -
sionandneuroticism independently, withanear-zerocorrelation between EandN
(H.J.Eysenck &B.G.Eysenck, 1964, 1968). TheEysenck Personality Inventory 
wasextended tochildren 7–16 years ofagebySybil B.G.Eysenck (1965), who
developed theJunior EPI.Neuroticism
StabilityExtraversionSuperego
PsychoticismIntroversion
F
FIGURE 14.5  Three-Dimensional Scheme Depicting One Individual ’s Scores on Each of 
Eysenck ’s Major Dimensions of Personality.Final PDF to printer