Dugdug.com interviews Dr. Cary Feria about her research


Speed haPhoto: Dr. Cary Ferias an effect on multiple-object tracking independently of the number of close encounters between targets and distractors

Interviewed by and Posted on dugdug, August 2013

Dr. Cary Feria is Associate Professor of Psychology and of Human Factors and Ergonomics at San Jose State University. Dr. Feria received her doctorate in Psychology from the University of California, Irvine, where she explored depth and distance perception. More recently, her research interests have centered around visual attention and human factors. Dr. Feria’s primary research focus is “multiple object tracking,” which refers to the ability to visually track several moving objects simultaneously. Her recent paper, titled “Speed has an effect on multiple-object tracking independently of the number of close encounters between targets and distractors” was published in the journal Attention, Perception, & Psychophysics.

Background of the study

The ability to visually track objects around us is essential to our capability to navigate our environment. The limitations of humans’ attentional capacities are most evident in cognitively taxing situations, such as when a driver navigates through a congested street, and when an air traffic controller attempts to prevent collisions while monitoring numerous aircraft. Understanding multiple object tracking has practical applications in the design of controls and displays for automobiles, airplane cockpits, and air traffic control systems.

Intuition tells us that the more quickly objects are moving, the worse we will be at tracking them (and research as evidenced this intuition!). However, it is also known that when the objects we are tracking pass close to one another, we tend to confuse the objects and have more difficulty tracking them. When objects are moving faster, they pass close to each other more often — So potentially it could be that fast motion does not actually make tracking harder, but that tracking is just worse at higher speeds due to the objects coming close to each other more often. Our study tested this possibility by using computerized displays in which the speed of the objects could be increased without increasing the frequency of objects passing close to each other.

Results and findings

Our study found that the faster the objects moved, the worse people tracked, even though the objects were not passing close to each other more often at higher speeds. So we concluded that higher speeds indeed make it more difficult to track objects. We also found that the greater the number of objects that had to be tracked, the larger the effect the speed had on people’s tracking ability. This suggests that when objects are moving faster, we need to use more of our attention in order to track each object; so when there are a large number of objects to track and they are moving quickly, we don’t have enough attentional resources to be able to track all the objects accurately.

About the department

The Department of Psychology at San Jose State University has Bachelors degree programs, as well as Masters programs in Experimental and Research Psychology, Clinical Psychology, and Industrial/Organizational Psychology. The faculty of Psychology are highly dedicated and student-oriented, and have a wide variety of basic and applied research interests. The San Jose State University Human Factors and Ergonomics Masters program is an interdisciplinary program that prepares students for careers involving the design of machines and equipment to be compatible with the human body and humans’ cognitive abilities and limitations.


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