Personality can not be determined by IQ testing. IQ tests are developed for testing of intelligence, or to be more precise, for measuring the so-called Intelligence Quotient.
The term “Personality” is used to describe typical patterns of behavior, thinking and emotions that remain relatively stable throughout person’s life. Personality trait is a tendency to act in a certain way, for example to be outgoing, extrovert or withdrawn and introvert. Other commonly recognised personality traits include openness, neuroticism and conscientiousness, another one is sapiosexual that is popular on internet. The concept of personality is among the most wooly and complex in psychology, and it often overlaps with the concept of temperament. Although widely disputed, and with many theories and approaches, personality theories don’t tend to include intelligence among personality traits.
Asking whether personality can be determined by IQ testing really makes very little sense: it neither can, nor is supposed to be.
It’s possible to ask whether IQ tests can measure the actual intelligence. It’s possible to ask whether personality tests can measure personality.
Both of these questions are rather vast and probably exceed the scope of this article. Many psychologists, only half-facetiously, simply assume that intelligence is the thing that is measured by IQ tests, and personality is what is measured by the personality tests.
There are certainly correlations between intelligence as established by IQ testing and performance. The strongest and most confirmed is the correlation between IQ scores and academic performance: it’s quite clear that the factor measured by IQ test is something that helps students perform well. There is also (more limited) evidence that IQ is correlated with income (although only to some extent, i.e. after reaching certain IQ, the relationship becomes weaker – it’s important to have a certain amount of intelligence, but having more and more doesn’t make much difference) and creativity (the relationship is similar to the one with income: up to the IQ of about 120, creativity is strongly correlated with intelligence, but not above that value).
IQ tests are by no means culture free, and are thus pretty useless in establishing differences between distinct groups of people, social classes, ethnic groups, nationalities or races. They are much better at comparing like-with-like, or people that come from similar social backgrounds and educational processes.
In addition to asking whether IQ testing is able to measure the “real” intelligence, it’s also possible to ask, and this is perhaps the most interesting avenue of thought emerging from the unfortunate formulation of this title, whether there is a correlation between intelligence, as measured by IQ tests and any personality traits (as measured by personality tests).
There are some documented (though not particularly strong) relationships between IQ and personality traits.
Perhaps the best known is the negative relationship observed between the trait of conscientiousness (a tendency to show self-discipline, act dutifully, and aim for achievement) and intelligence. Conscientiousness appears to be negatively related to fluid intelligence (the part of intelligence independent, or less dependent on acquired knowledge), but not to crystallized intelligence (ability to use acquired knowledge). Not all studies confirm this result, though.
One fascinating study reported that personality correlates of intelligence changed with age. In younger adults, openness and extroversion were good correlates of cognitive ability, while in older adults, agreeability was inversely correlated to intelligence – disagreeable nature was connected to higher cognitive functioning.
All these studies were of correlative nature: there is no way to establish whether intelligence causes those personality traits, whether those personality traits help people increase intelligence, or whether some other factor influences both variables.
Sources and references:
http://www.era.lib.ed.ac.uk/handle/1842/2373
http://en.wikipedia.org/wiki/Big_Five_personality_traits#Conscientiousness
Intelligence Change From Younger To Older Adulthood. ScienceDaily. Retrieved January 25, 2010, from
http://www.sciencedaily.com /releases/2006/08/060811092500.htm