Fall 2006

h_greene Harold Greene seeks a better understanding of visual perception

While we may see things one way, Associate Professor of Psychology Harold Greene sees things differently—literally. As a researcher of visual perception, Greene’s projects analyze a variety of visual attention processes involved in how we perceive visual scenes.

“I have an eye tracker in my lab, and I use it as a window into moment-to-moment processing as we make sense of our visual environment,” says Greene.

“The eye tracker allows me to study such variables as when and where the eyes move.” Currently, Greene teaches courses in experimental psychology and perceptual/cognitive psychology as well as learning and memory.

At University of Detroit Mercy since 1999, Greene received his Bachelor of Psychology from Queen’s University, Canada before receiving a Ph.D. in Cognitive/Experimental Psychology from the University of Georgia. Prior to joining UDM, Greene held research fellowships at the Center of Excellence for Research on training in Atlanta, and at the University of Massachusetts, Amherst.

Why Detroit? Greene says he liked its urban environment and proximity to Canada, but was primarily attracted to the interesting, committed faculty at UDM.

Tracking eye movement

Greene’s current research projects treat visual search as a problem space in which the task is to narrow the distance between where the searcher is currently looking and where the target object is located.

“I've been doing some computational simulations of the process and, when the target is found by the simulation routines, they replicate existing human search data quite well,” Greene says. “This occurs without any assumption of knowledge of the search environment. I'm now working on refining the simulations with information from human visual search performances.”

In addition, Greene is interested in how familiarity influences visual searches. According to Greene,

“Familiarity is obviously an important factor in real-world visual search: imagine yourself as a security officer looking for a familiar ‘Wanted’ face among unfamiliar faces at a security line.” Recently, he provided evidence that the perceptual span, which is the area from which useful information is obtained during an instance of looking, is narrower when the non-targets are unfamiliar.  So, ultimately, what inspires the pursuit of visual processing? Says Greene, “In the lab, we try to understand visual processing towards being able to predict visual processing. If we understand how things work and can predict when they are going to work/fail, we may be able to control the operations. If we don’t know how visual processing works, it’s difficult to suggest ways to facilitate processing, as in the case of airport baggage screeners, or to mend visual disorders.”

Many components compose Greene’s areas of interest. “My work contributes to the published body of knowledge on visual processing. In science, we’re always asking questions and learning a little bit more about nature,” he says. “In my case, I’m learning about visual processing. The findings serve to inform and constrain real-world visual processing-related interventions, and to satisfy intellectual curiosity.”

Some of Greene’s early work on visual search in “shoot, no-shoot” situations have been featured on CNN, and in the Atlanta Journal & Constitution. “A ‘shoot, no-shoot’ situation occurs when a law enforcement officer is faced with making a split-second decision to shoot or not shoot a potential perpetrator,” Greene explains.

“If the officer’s moment-to-moment assessment of the visual scene is incorrect, he/she may shoot an innocent person, or may himself/herself get shot.”

Greene sees a strong correlation between his research and his role in the classroom. “My research is very relevant for the courses I teach.  I discuss the empirical studies that allow us to theorize about how the mind works. I try to get the students to understand that we must always search for better explanations of the mind,” he says.

For the contents of his courses, better explanations come by way of experimentation. With respect to this, Greene says, “As an experimenter myself, I believe that I help students to learn how to ask research questions and to seek answers to questions about the mind.”

Students are part of his research

As a professor, Greene also sees the need to involve his students in his research. Each semester, undergraduate students with high GPAs and an aptitude for experimentation are invited to join his lab. “I think it’s a good learning experience for them because they are exposed to the practical aspects of research...doing science, as opposed to learning about science,” Greene says. New members are trained to use the lab equipment by old members. All members assist with stimulus design; they also conduct experiments and perform data analysis.

“It would be difficult to run my research program without the help of the students,” says Greene. “They really are the focus of my work at UDM.”

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