Personality psychologists are interested in what differentiates one person from another and why we behave the way that we do. Personality research, like any science, relies on quantifiable concrete data which can be used to examine what people are like. This is where the Big Five plays an important role.
The Big Five was originally derived in the 1970's by two independent research teams -- Paul Costa and Robert McCrae (at the National Institutes of Health), and Warren Norman (at the University of Michigan)/Lewis Goldberg (at the University of Oregon) -- who took slightly different routes at arriving at the same results: most human personality traits can be boiled down to five broad dimensions of personality, regardless of language or culture. These five dimensions were derived by asking thousands of people hundreds of questions and then analyzing the data with a statistical procedure known as factor analysis. It is important to realize that the researchers did not set out to find five dimensions, but that five dimensions emerged from their analyses of the data. In scientific circles, the Big Five is now the most widely accepted and used model of personality (though of course many other systems are used in pop psychology and work contexts; e.g., the MBTI).
For the past several years, we have been using the Big Five to study personality in terms of how it changes over time and how it relates to other variables (such as self-esteem and music preferences). During this period of time, we have collected personality data from literally millions of people from around the world.
Analyses of the data have revealed a number of interesting findings about personality, and have allowed us to identify some major patterns in our personalities. For example, contrary to the then prevailing view, our findings suggest that personality is not “set like plaster” at age 30; instead it continues to change, with the exact pattern of change depending on the trait.
We want to emphasize that we are talking about generalizations here, and these generalizations don't apply to all people. To illustrate, consider the generalization that men are generally taller than women. This does not mean that every man is taller than every woman. Instead, it means that, on average, men are taller than women. This same logic applies to the feedback that is given on this site. Even though, on average, people tend to become more conscientious as they get older, not everyone follows this pattern.
1. What is the feedback based on?
All the feedback you see here is based on statistical analyses of personality data collected from over 10,000 people. None of the feedback is based on our intuitions or theories about personality. In short, the feedback is entirely driven by the data we have collected.
2. Why is the feedback sometimes very different from how I see myself?
The feedback is not meant to suggest that that everyone who scores high on Extraversion (or another trait) will be exactly as we describe them. As noted above, the feedback is based on generalizations derived from our research and from the work of other researchers in the field. It is inevitable that some people will not fit in with these generalizations. If you feel the feedback did not match you very well, this could be one reason why.
3. Where do the personality questions come from?
The questions come from our research and research by others on personality, lifestyles, values, and attitudes. The Big Five questions used in this site are from an instrument known as the Big Five Inventory (developed by Oliver John at UC Berkeley). Most of the other questions are written by current academic researchers investigating various hypotheses about personality.
4. Why does the feedback sometimes give contradictory information?
Sometimes the feedback will give respondents apparently contradictory feedback. This is an unfortunate consequence of making generalizations. Quite often, individuals cannot be captured by the general trends derived from analyses of large numbers of people. Of course, while our generalizations do get it wrong sometimes they tend to get it right more often than not.
5. Why were there questions about location?
As part of our research we're interested in regional differences in personality. Some of our analyses suggest that people living in different regions of the U.S. have different personalities. To develop an understanding of the nature of those differences, we've examined the links between a region's personality and various features of its environment. For example, we find that a state's personality is related to precipitation (places with higher precipitation have higher rates of Neuroticism), population density (dense areas are associated with higher Openness and lower Agreeableness), ethnic diversity (diversity is related to higher Openness), and a host of other findings ranging from voting behavior to health and mortality. One question that arises from this is whether the environment shapes personality, or whether people select environments that reinforce their personalities, or whether some other variable affects both personality and the other factors. It could be that people high in Openness move to places that are densely populated and culturally diverse. Alternatively, living in densely populated and culturally diverse place may cause people to become more open. The reason why we currently ask about birthplace, place of residence, and how long participants lived in each is so that we can examine this issue of the causal direction between personality and environment.
We ask people how much they like/liked living in a certain place because we're interested in whether people prefer living in regions where their personalities “match” the personality of the region. If, for example, a person is open and disagreeable, would he or she prefer living in a place where the average person is also open and disagreeable, or in a place where the average person is narrow minded and agreeable? This idea draws from research on person-environment fit, which indicates that people seek and create environments that reflect and reinforce their dispositions and self-views. Fit between persons and their environments has been linked to a wide range of physical and mental health consequences.
6. Where can I learn more about the Big Five?
http://www.personalitylab.org/: This site has a number of Big Five-based studies from Dr. Oliver John's group at UC Berkeley.
http://www.personalityresearch.org/: This provides an accessible overview of the academic field of personality.
http://www.rap.ucr.edu/: Home page of lab of very well respected researcher - will give you an idea what it is personality researchers do!
http://webspace.ship.edu/cgboer/perscontents.html: An online textbook that will give the reader a basic background on personality psychology.
https://gosling.psy.utexas.edu/: One of this site's researcher's homepage, which contains more information and results from studies using data from this site
Finally, The following citation may be of use to those interested in understanding more about the Big Five: John, O. P., & Srivastava, S. (1999). The Big Five trait taxonomy: History, measurement, and theoretical perspectives. In L. A. Pervin, & O. P. John (Eds.), Handbook of personality: Theory and research (pp. 102-138). New York: Guilford Press.