This study investigates the relationship between intelligence test per
formance, a test of visual inspection time (IT) and personality and te
mperament dimensions. Howe's (1990) hypothesis that IT and IQ are empi
rically related because of personality or temperament variables is eva
luated and rejected. IT and performance IQ (PIQ) were significantly re
lated independent of personality or temperament variables. IT and verb
al IQ (VIQ) mere unrelated. Robinson's (1989) hypothesis that ambivert
s (moderate extraversion) perform significantly better on IQ tests was
examined and supported. Ambiverts performed significantly better on v
erbal and performance measures of the Wechsler Adult Intelligence Scal
e-Revised (WAIS-R) and on the Raven's Advance Progressive Matrices (AP
M). Mobility from the Strelau Temperament Inventory (STI) was also rel
ated to performance IQ (PIQ) and Raven's test scores. These results su
ggest an important role for the concepts of arousal and/or arousabilit
y in a biological model of intelligence. Implications for intelligence
assessment are discussed.