Some claim culture affects our basic visual perception

In new experiments conducted by the UCLA researchers, white, Asian American and recent Asian immigrant college students in the U.S. performed similarly on the test, known as the rod-and-frame task, which measures the influence of surrounding contextual visual information on perception.

The findings, published in PLOS One suggest that the basics of visual perception, such as object orientation, are largely independent of cultural variation and apply broadly across human populations.

What is the rod-and-frame task and what is the debate?

The rod-and-frame task asks participants to view a single line within a square frame and to orient that line straight up and down vertically. The difficulty comes when the surrounding frame is tilted in various ways, which can influence viewers' perception of the vertical orientation of the line.

Historically, much of this type of research had been conducted in Western countries with college students as participants, raising questions about how accurate the data is for people in other cultures and parts of the world.

In some previous, highly publicized work produced since 2000, researchers exploring that question found that East Asians and Europeans performed differently on the rod-and-frame task; East Asians, the researchers said, tended to focus on the square frame first or give equal attention to the frame and the line, while Europeans placed more emphasis on the line.

These researchers hypothesized that cultural influences could be at the root of the differences, with participants from East Asian cultures, which social scientists say emphasize the embeddedness of individuals within collective groups, perceiving more holistically and taking context into consideration. Similarly, participants from Western cultures, which social scientists say tend to elevate individuals over groups, may perceive more analytically and independently of context. The claims bucked against a fundamental assumption in visual neuroscience research that basic visual functions are the same for humans everywhere, as well as for non-human primates.

"If culture influences even the most basic visual functions, then all studies must take into consideration the cultures of the participants and the fact that findings might not apply to other cultures," said Zili Liu, a UCLA psychology professor and the current study's corresponding author. "Perhaps more importantly, vision research with animals will have limited utility."

If these previous findings were true, Liu noted, it would stand to reason that people who have been immersed in another's culture for enough time will start to perform similarly to people raised in that culture on the rod-and-frame task.

"I thought UCLA was a good place to test this because we have many Asian American students, as well as more recent Asian immigrants to the U.S., and they should serve as supportive evidence that the longer people have lived here, the less the data would look like Asian nations," Liu said.

Reassessing the influence of culture on the rod-and-frame task

Chéla R Willey, a UCLA doctoral student at the time of the study who is now an assistant professor at Loyola Marymount University, recruited a diverse group of 342 UCLA students to perform the rod-and-frame task using virtual reality goggles. All participating students answered a questionnaire about their ethnicity and country of citizenship. In this first experiment, participants used a computer mouse to rotate the center line to make it vertical.

In a second experiment, 216 of the 342 students judged whether the line was clockwise or counter-clockwise with respect to the vertical.

Among the 84 East Asian participants who completed both experiments, 40 were second-generation Americans (born in the U.S. with at least one immigrant parent) or beyond and 44 were first generation or non-citizens. Among the white dual-experiment participants, nearly all -- 51 out of 57 -- were second-generation Americans or beyond, while six were first generation or non-citizens.

The results of the first experiment revealed that a participant's cultural background had little, if anything, to do with how they judged the line's vertical orientation inside both tilted and non-tilted frames. In the second experiment, the researchers once again found no significant difference between ethnicity or generation. They did, however, observe a well-known gender difference in which frame tilt affects the perception of women more than men.

"The gender finding replicates what has been found in many other studies, indicating that our data are of reasonable quality," Liu said. "Our failure to replicate the cultural effect therefore suggests that culture might not influence orientation perception that much."

The work lends support to research showing that some basic mechanisms of visual perception are universal and that for these kinds of studies, it might not matter much which population the researchers use.