European Americans are more likely than Asian-Americans to judge an individual's personality based on behaviors, such as presuming someone who, say, won't touch a door handle is neurotic, a new study suggests.

The key is cultural, according to the researchers. European American culture emphasizes individual independence; meanwhile, Asian culture is more interdependent and more sensitive to social contexts. This difference means European Americans are inclined to account for someone's behavior by making assumptions about their personality, while Asians are not (at least not without some context), according to the researchers.

"Culture can be very important in shaping some fundamental aspects of the human mind," said study researcher Shinobu Kitayama, a professor of psychology at the University of Michigan. "This study is one example of a demonstration that culture can influence what appears to be a very deep part the human mind, something that happens automatically and continuously."

Personality testing

To test for this particular cultural difference, the researchers recruited European American and Asian- American students at the University of Michigan. The Asian-Americans were born in Asia and had spent at least several years in their home country before moving to the United States. [Face Recognition Varies by Culture]

In the first part of the study, the participants were given what they believed was a memory test, and asked to learn faces paired with behavior — for instance, when shown an image of a woman called Julie, they were told she checks the fire alarm every night. The faces were the same race as that of the participants.

"Some people make the immediate inference about what kind of person Julie is based on this behavior: Julie is very neurotic or Julie is very cautious," Kitayama said. "That is the effect we wanted to capture."

The participants were then shown the face followed by a series of single words, either similar to the implied trait or irrelevant to it. In Julie's case, these could be "cautious" or "outgoing," respectively. They were also shown random groups of letters. Kitayama and fellow researcher Jinkyung Na, also of the University of Michigan, asked them to identify what they saw was an English word or not, and they also measured the participants' reaction time.

This experiment was based on the idea that the image would make the participants more responsive to words relating to personality traits associated with the person. They saw that European Americans reacted more quickly to the relevant words and more slowly to the irrelevant words; meanwhile, there was no difference in reaction time for Asian-Americans.   

A second study confirmed this difference by looking at brain activity. The researchers once again showed the participants’ faces paired with behavior and followed this by showing them the faces again followed by similar or contradictory words or random letters.

Among the European Americans, they saw a spike in electrical activity in the brain, an indication of surprise, when the contradictory words appeared.

"The effect size is very huge for European Americans, but there is none for Asian-Americans," Kitayama said. "There is a very pronounced difference."

In fact, European Americans even registered some surprise at traits that were consistent with the person's behavior. Kitayama attributes this to variations in the traits the participants inferred — someone might label Julie as "cautious," while someone else might think she is "absolutely neurotic," he said.

Cultural influences

Other research has shown that Asians pay more attention to context than European Americans. In a study published in 2003, Kitayama and colleagues found that when shown a box with a line it, then shown an empty box and asked to draw a line the same absolute length as the previous line — regardless of the size of the box — North Americans outperformed Japanese. However, when the task was altered so that the participants had to draw a line of the same proportion relative to the box as the line they had seen earlier, the Japanese had the advantage.

There is also evidence that Latin Americans have an interdependent mindset, perceiving people and behaviors as part of a larger picture, similar to that of Asians, and that Western European culture falls between Asians and North Americans in terms of interdependence and independence. American history of settlement in low-density, harsh environments may account for Americans' stronger culture of independence, according to Kitayama.

And some parts of the United States show more of an independent mindset than others. In a previous study, Kitayama and Michael Varnum of the University of Michigan found residents in newer states give their babies more unique names.

The most recent study, which will be published in an upcoming issue of the journal Psychological Science, adds to other work being done in cultural neuroscience, a field that has begun to investigate brain processes as a function of culture, Kitayama said.

"One interesting question is, 'To what extent is this coming from experience and to what extent from some genetic predisposition,' because right now we don’t know," he said.

You can follow LiveScience writer Wynne Parry on Twitter @Wynne_Parry.