The Return of the Invisible Gorilla: Experts Aren't Immune to this Psychological EffectEmerging research is following up on the invisible gorilla.

In a classic study, researchers asked subjects to watch a video of two groups of people passing a basketball and count the number of passes by one of the teams or keep count of bounce passes vs. aerial passes. Engrossed in the task, half the subjects failed to notice a person in a gorilla suit walk through the video scene.

This phenomena is called inattentional blindness (IB) and a new study from Brigham and Women’s Hospital (BWH) in Boston discovers that even expert searchers, operating in their domain of expertise, are vulnerable to IB.

“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,” said Trafton Drew, Ph.D., a postdoctoral researcher at BWH and lead author on this study.

“We found that even experts are vulnerable to this phenomenon.”

In the study, published in Psychological Science, 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.

Researchers found that 83 percent of radiologists did not report seeing the gorilla even though eye-tracking technology 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, Ph.D., 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 they stress that even this high level of expertise does not immunize against inherent attentional limitations of what we perceive.

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.

Source: Brigham and Women’s Hospital

Eye with line shining from it photo by shutterstock.