Research Roundup

Psychology graduate students are involved in a host of innovative research projects addressing many aspects of the human brain, body and behavior. Here are some brief profiles of student researchers-how they got started and where their research is going.

Investigating human perception

The world is a whirl of complicated movement, says Bridgette Martin, a third-year cognitive psychology student at Stanford University-yet people somehow segment fluid actions into logical steps, she says.

"Imagine being on a busy street surrounded by people moving around, changing speeds and directions-cars whizzing down the road," says Martin. "How do we make sense of that?"

To answer this question, Martin created two animated events that her college freshman participants had never seen before, one showing three shapes playing hide and seek and the other featuring a large triangle bullying two smaller ones. Participants pressed a space bar to indicate where they thought one action ended and another began- for example, after a shape seemed to run behind a wall.

The students almost always agreed with each other about where breaks in the action occurred, says Martin. And when asked to segment the videos into a handful of episodes, the students identified these large events as groups of the small actions they had already identified, suggesting that participants organized the shapes' actions into a hierarchical framework, she says.

Even when Martin showed the videotapes backwards, making the shapes' movements seem arbitrary and purposeless, the participants easily parsed the action-placing breaking points almost exactly in alignment with those of the forward-played video, she reports.

The findings suggest that people do not need to understand what is going on to mentally organize what they see, says Martin. And being able to do this, she adds, is critical to navigating a complicated world, as a pedestrian crossing an intersection must. The ability also could be critical for young children as they learn to make sense of what they see.

"If you don't have any way of parsing what you observe into events, it would be hard to learn language, applying labels to distinct actions," she says.


 

Appraising aging apes

Unlike humans, apes do not demonstrate memory deficits as they age, suggests past research. But Chris Kuhar, a fifth-year comparative psychology graduate student at the Georgia Institute of Technology, suspects that previous tasks simply haven't been sensitive enough to detect the animals' cognitive decline.

To test this theory, he is measuring the working memory of 16 apes from three to 44 years old-about five to 70 in human years. In full view of the animal, Kuhar places a piece of food underneath one of four cups and, after a delay of up to 90 seconds, allows the ape to find the treat.

His preliminary findings show that younger animals seem to have better working memory than the older ones. They often pick up the cup covering the food on the first try, reports Kuhar, while many of the older animals appear to forget where the food was placed, especially after long delays.

The results suggest that aging apes experience memory problems similar to those of aging humans, says Kuhar, which could mean that his and other's gorilla research could uniquely contribute to scientists' understanding of human cognitive decline, he says.

"Gorilla studies don't have any of those confounding factors that exist in human studies," he says. "They all have the same education and socioeconomic status, they don't use drugs and they don't drink."


 

Measuring relational aggression

Relational aggression-intentionally hurting another through social means such as spreading rumors-has been well-documented in books such as "Queen Bees and Wannabes" and the film it inspired, "Mean Girls." But according to Brittany Pendry, a developmental psychology student in her fifth year at Indiana University, Bloomington, no one has developed a way to measure this quiet assault, which some researchers say can cause anxiety and depression, especially in school-aged girls.

Pendry is now trying to remedy that gap. She started by combining past research for concrete examples of relational aggression, like telling friends to ignore a particular classmate or saying cruel things about another student. She is now asking girls recruited from Bloomington middle schools how often these insults happen to them.

Once she has determined which kinds of relational aggression occur among girls in this age group, Pendry will statistically validate her test, which she hopes will be used by school counselors and psychologists to identify children who experience this kind of violence.

"One of the biggest problems right now is these girls are under-identified," Pendry notes-perhaps due to their reluctance to speak up, ask for help and potentially attract more negative attention from their peers, she says.


 

Observing brain cells

Neurons known as head direction (HD) cells keep track of the direction an animal's skull points-an important function if you don't want to feel disoriented every time you turn your head, says James Engle, a third-year graduate student at California State University, Sacramento, who studies the cells.

Previous research has found that the cells perform their feat by favoring a particular direction and then signaling more often when the head matches the neuron's preference-so that a leftward favoring cell will tend to fire more when the head points left of the body.

But Engle may have found an exception to this rule: During sleep, HD cells may completely lose their directional preferences, he says. He observed this phenomenon by placing an electrode next to a single HD cell in the brains of rats and recording its directional preference. Engle then placed the animals in cylindrical enclosures that encouraged them to sleep with their head pointed to the left or right.

As the rats slept, the HD cells began firing regardless of the head's direction, with right-preferring cells sending signals even when the animal's head faced left, and vice versa.

Based on these findings, Engle suspects that the HD cells' direction-neutrality may enable the brain to consolidate previously learned spatial knowledge during sleep, since sleeping HD cells cannot interrupt this process with irrelevant head direction information.


Surveying understudied populations

Being labeled a "model minority" has caused Indians living in the United States to be largely overlooked by psychological researchers, says Gagan Khera, a fifth-year clinical psychology student at the George Washington University. But with the help of an award from the National Institutes of Health, Khera hopes to assess the cultural identity of first- and second-generation Indian-Americans and see how it relates to mental health and substance abuse.

Khera recruited 1,000 people who were born in India-or whose parents were born there-through college, cultural, religious and professional organizations. Participants filled out a survey online that consisted of measures such as the Center for Epidemiology Depression Scale, an inventory of substance use behaviors including smoking and drinking, and the Abbreviated Multidimensional Acculturation Scale, which gauges how strongly a person identifies with American or Indian values.

She also plans to examine how much social support the participants receive from such people as their friends, parents and siblings. Having friends or family willing to aid in times of crisis may protect Indian-Americans from the stress of living as minorities in a different culture, she conjectures.

Generational differences may also emerge, says Khera, who notes that researchers disagree as to whether first- or second-generation Indian-Americans more often experience problems such as depression and alcohol abuse.

"Some literature argues that in fact the second generation born in the United States is likely to feel more conflicted and have more problems," she explains. "Other literature shows that the first generation has more struggle, depression and feelings of loneliness."

-S. DINGFELDER