When Diaz became offended, the other student tried to pass off the question as a joke. But it did not amuse her, any more than the idea of Mexican-themed parties on Greek Row featuring students in sombreros and fake mustaches.
"Because of the society we live in, it's not OK to be overtly racist," Diaz said. "But that doesn't mean everything is OK."
Some call it the new face of racism — not the blatant acts of bias that recently led to the
Students are sharing their experiences with microaggression on websites and Facebook pages at Harvard, Oberlin, Brown, Dartmouth, Swarthmore,
In the last eight years, researchers have conducted more than 5,500 studies on the topic documenting how such seemingly minor slights harm student performance, mental health and work productivity, said Derald Wing Sue, a Columbia University psychology professor and leading expert on the topic.
University of California President Janet Napolitano invited faculty members last year to take training in recognizing microaggression and the messages they send. One handout, adapted from Sue's research, offered examples: Telling people of color they speak English well sends a message they are perpetual foreigners in their own land or asserting that America is a "melting pot" denies the significance of a person's racial or ethnic experiences.
Some critics, however, say they worry that the microaggression movement chills free speech, increases conflict and perpetuates an aggrieved sense of victimhood.
Bradley Campbell, a an associate professor of sociology at Cal State Los Angeles, said the movement is transforming society from a "dignity culture," in which people are taught to have thick skins and refuse to allow others to affect their sense of self-worth, to a "victimhood culture" that advertises personal oppression.
Such a shift, he argued, could increase mental health problems and 1st Amendment conflicts, such as campus speech codes and the recent attempt by University of Missouri students to bar journalists from entering a public area they deemed their "safe space."
He also said that labeling those who unintentionally offend as aggressors seemed harsh, potentially creating more conflict and alienation among groups.
Others defend the focus on microaggression as the next step forward in the country's long, slow march toward greater equality and understanding.
Rini Sampath, USC's student body president of Indian descent who drew national attention when she wrote on Facebook about an ethnic slur hurled at her, said microaggressions should not be shrugged off as trivial.
"People are going to dismiss us … because they say it's political correctness gone too far," she said. "But every day, students walk into a room and someone makes fun of their accent or [gets] kicked out of parties, and we have to take those things seriously. Microaggressions lead to macroaggressions."
Jerry Kang, a professor of law and Asian American studies at UCLA, said explicit bias may be less visible today, but a growing body of mind-science research has documented that even people who don't consider themselves bigoted take actions belying that. Such implicit biases have been correlated with such behavior as job interview callbacks, hiring men over women, use of police force and funding of minority student organizations, he said.
"The microaggression conversation has helped all of us," said Kang, who was named this year as UCLA's first vice chancellor for equity, diversity and inclusion. "Having multiple vocabulary and methods for measuring how fair and square we are is always a good thing for society."
But students say it's not always easy to call out such slights. At UC Berkeley, Spencer Pritchard, a biracial student majoring in political economy and African American studies, said he tried to laugh off jests by his white and Asian American floormates who expressed surprise that he was articulate and good at math.
"After the fact, I got frustrated and wondered why I let that slide," he said. "I'd like to not let it bother me if I didn't see black people disproportionately going to prison, dying at the hands of police or being pulled by their hair in classrooms. Microaggressions are part of a bigger picture."
At UCLA, Filipino American student Kevin Casasola said he has learned to recognize the harm caused by seeming innocuous slights and is more willing to voice his discontent with them. He said his peers will sometimes ask where he is "really from" after he tells them he was raised in Temecula.
"The covert underlying message is 'Oh, I don't believe you're from here,'" said Casasola, a third-year statistics major. "It perpetuates an idea of xenophobia."
At USC, undergraduate student leaders escalated their campaign against campus bias Tuesday, passing a resolution asking the university to hire administrators to oversee diversity, hold sensitivity trainings and set aside $100 million for scholarships, programming and mentorships for minority students and faculty.
One resolution supporter was Leslie Berntsen, a psychology graduate student whose mother is Nicaraguan and father, white. When she was applying to graduate schools, she said an admissions officer expressed surprise at her high test scores and encouraged her to apply for a scholarship for minorities.
"The implication is that Hispanics couldn't score so high on tests," she said.
Berntsen said that such incidents don't compare with problems of previous generations but are a sign that society still is struggling with race.
"Just because we're doing better doesn't mean we're doing good," she said.
A testy exchange before the vote on the resolution highlighted the continuing tensions in the microaggression debate.
A white male speaker, apparently frustrated by the discussion, questioned the need for diversity training for guest lecturers and whether one student was human at all. He told the packed room that "you guys don't understand how endowments" and university finances work.
Several students groaned, and Cynthia Blondeel-Timmerman, a junior, told the speaker she found the term "you guys" offensive.
"This isn't a men's issue," she later said. "How dare you come into this space and say that [females] aren't important."
Shortly afterward, he left in a huff, declining to give his name.