Personality is a set of characteristics that tends to influence a person's behavior. If you have a friend who you think is aggressive, then you expect them to be confrontational or argumentative. Of course, he won't be argumentative in every situation. He may be rather passive when being given by a lecture by his boss, even though he is prone to argue with the umpire at a softball game.
This observation that people's behavior depends both on their personality characteristics and the situation they are in has created a tension within research on personality. Are your actions determined mostly by your personality? Are situations more important?
This issue was explored in an interesting paper by Ryne Sherman, Christopher Nave, and David Funder in the August, 2010 issue of the Journal of Personality and Social Psychology. There has been a lot of work examining how personality affects behavior, and also how situations influence the way people act. The authors of this paper, though, had people provide information about four different situations they encountered and had them describe the situation and their actions within that situation.
The basic results were probably not that surprising given all of the previous research. The situations that people encounter influence their behavior, but personality characteristics also matter. That is, an aggressive person will tend to act aggressively, but he will be most likely to display this aggression in situations where it is appropriate to be aggressive.
Perhaps the most interesting finding in the study, though, comes from the interaction between personality and situations. People with particular personality characteristics seem to seek out situations in which they can display core aspects of their personality. That is, your aggressive friend will tend to put himself in situations in which he can be aggressive. A friend who is very open to experiences will tend to find new situations in which she can explore new things.
How did the authors reach this conclusion?
The participants in the study were given particular days in which they had to describe their activities at a specific time of day. So, the participants were not free to choose which situation they described. Nonetheless, there was a high degree of similarity in the types of situations that a given person would be in across days and times of day. Different people participated in different situations, though, so it wasn't just that everyone had a similar set of experiences. Furthermore, the situations that people encountered tended to be ones that were compatible with their personality characteristics.
These results suggest that people generally seek out situations that fit within a comfort zone that is defined by their personality characteristics. So, even though your aggressive friend knows that there are situations in which he can't display aggression, he will find those situations in which he can be aggressive.
Finally, this study also demonstrated that not everyone is consistent in the way they display their personality. That is, we all know some people whose behavior is very consistent from day-to-day and situation-to-situation. We know others where we wonder which version of that person will show up on any given day. The data from this study suggest that, people who are low in emotional stability tend to exhibit a variety of behaviors that are not all consistent with what measures of personality would predict. In contrast, people who favor conservative values tend to be more consistent in their behavior across situations.
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