If you're not looking for it, you probably won't see it

(Press-News.org) Boston—If you were working on something at your computer and a gorilla floated across your computer screen, would you notice it? You would like to think yes, however, research shows that people often miss such events when engaged in a difficult task. This is a phenomenon known as inattentional blindness (IB). In a new study from Brigham and Women's Hospital (BWH) in Boston, researchers have found that even expert searchers, operating in their domain of expertise, are vulnerable to inattentional blindness. This study published this week Psychological Science.

"When engaged in a demanding task, attention can act like a set of blinders, making it possible for stimuli to pass, undetected, right in front of our eyes," explained Trafton Drew, PhD, post-doctoral researcher at BWH and lead author on this study. "We found that even experts are vulnerable to this phenomenon."

The researchers asked 24 radiologists to perform a familiar lung nodule detection task. They examined five scans; each scan contained an average of 10 nodules. A gorilla, 48 times larger than the average nodule, was inserted in the last scan. The researchers found that 83 percent of radiologists did not report seeing the gorilla. With the help of Melissa Le-Hoa Vo, post-doctoral researcher at BWH, the researchers tracked the eye-movements of the radiologists and found that that the majority of those who missed the gorilla looked directly at it.

"The radiologists missed the gorillas not because they could not see them, but because the way their brains had framed what they were doing. They were looking for cancer nodules, not gorillas," explained Jeremy Wolfe, senior psychologist and director of the Visual Attention Laboratory at BWH. "This study helps illustrate that what we become focused on becomes the center of our world, and it shapes what we can and cannot see."

The researchers note that it would be a mistake to regard these results as an indictment of radiologists and stress that even this high level of expertise does not immunize against inherent attentional limitations of what we perceive. The results suggest that even expert searchers typically only see what they are looking for, and are often unaware of the unexpected. The researchers hope that the results will lead more expert searchers to recognize the important role of attention in determining what the searcher will find and what they may miss.

### This work was funded by a NRSR post-doctoral fellowship from the NIBIB to TD.

Brigham and Women's Hospital (BWH) is a 793-bed nonprofit teaching affiliate of Harvard Medical School and a founding member ofPartners HealthCare. BWH has more than 3.5 million annual patient visits, is the largest birthing center in New England and employs more than 15,000 people. The Brigham's medical preeminence dates back to 1832, and today that rich history in clinical care is coupled with its national leadership in patient care, quality improvement and patient safety initiatives, and its dedication to research, innovation, community engagement and educating and training the next generation of health care professionals. Through investigation and discovery conducted at itsBiomedical Research Institute (BRI), BWH is an international leader in basic, clinical and translational research on human diseases, involving nearly 1,000 physician-investigators and renowned biomedical scientists and faculty supported by nearly $625 million in funding. BWH continually pushes the boundaries of medicine, including building on its legacy in organ transplantation by performing the first face transplants in the U.S. in 2011. BWH is also home to major landmark epidemiologic population studies, including the Nurses' and Physicians'Health Studies, OurGenes and the Women's Health Initiative. For more information and resources, please visit BWH's online newsroom. END