Force Science News #225:

New "invisible gorilla" study adds to proof of "inattentional blindness"

Force Science Research Note: The Force Science Research Team is moving into the final stages of an intricate study of various time factors associated with a human being falling. In association with this project we are gathering footage of individuals falling in any fashion after being shot or receiving an ECD application. If you have footage you would be willing to share for use in this research study please e-mail us at: All inquiries and assistance will be held confidential.


In this issue:


I. New "invisible gorilla" study adds to proof of "inattentional blindness"


II. FS instructor offers insights into chief's comments on officer suicides


III. Launch date set for special public lectures on LE research


I. New "invisible gorilla" study adds to proof of "inattentional blindness"


Additional evidence of the phenomenon known as inattentional blindness has emerged from a new study of sensory focus and memory, this time with a professional group other than cops.


"At Force Science, we write and teach about inattentional blindness in a law enforcement context," says Dr. Bill Lewinski, executive director of the Force Science Institute. "But this behavioral happening is by no means limited to police work--which, in fact, lends credence to its frequent occurrence in use-of-force encounters."


Inattentional blindness (IB) refers to the tendency of the human brain to aggressively filter out visual images that are irrelevant to a captivating primary task that an individual is pursuing, even though these images are clearly within the person's field of view. Later, when the subject claims not to remember these images, he or she may be perceived as lying.


In a police context, the phenomenon may arise, for example, during a shooting when the involved officer is so intently focused on reacting to a threat that he or she fails to notice or later recall other blatantly obvious elements or actions simultaneously present in the surrounding environment, a memory blank that gets interpreted as willful deceit.


You may be familiar with the classic "Invisible Gorilla" film that features two intermingling groups of young people moving around as they pass basketballs back and forth. Viewers are told to concentrate on and count the passes made by one group. Part way through the film, a large person in a black gorilla suit strolls into the scene, stands amidst the basketball crowd, beats on his chest while facing the camera, and then slowly exits.


Later the vast majority of viewers who have never seen the film before say they did not notice the gorilla at all and are stunned upon replay to see how obvious it was. "They were 'blind' to him," Lewinski explains, "because their narrowed focus of attention was on something else within their field of view."


The new study, conducted by researchers from Harvard University and the Visual Attention Laboratory at Brigham and Womens Hospital in Boston, documents the same effect among highly skilled radiologists, a group known for exceptional expertise in observation that they have honed for years.


Twenty-four top-notch radiologists were asked to participate in common and familiar lung cancer screening. They were to scroll freely through computerized images or "slices" of lung tissue, looking for small circles of light that would signify malignant nodules. Each case series they examined contained an average of 10 nodules, and the doctors were to click the locations of these abnormalities while outfitted with eye-tracking equipment.


In the last of these cases, the researchers had inserted a picture of a black gorilla outlined in white into five slides of tissue sections. "The gorilla was over 48 times the size of the average nodule in the images," the team writes. In other words, about the size of a matchbook. The gorilla picture was situated near a lung nodule "so that both were clearly visible."


Detecting the suspect nodules "was challenging, even for expert radiologists," the researchers note, so they were fully engaged in the search. They scrolled through the slices containing the gorilla an average of 4.3 times, with "ample opportunity" to study them.


Yet when questioned later, 20 out of the 24 expert observers--more than 83%--had failed to notice the unexpected but intrusive gorilla. The eye-tracker revealed that those who missed the beast spent nearly six seconds reviewing the tissue slices with him in them, with more than half looking "directly at the gorilla's location."


The researchers note: "This is a clear illustration searchers are not immune to the effects of IB, even when searching...images within their domain of expertise.... When engaged in a demanding task, attention can act like a set of blinders, making it possible for salient stimuli to pass unnoticed right in front of our eyes...."


In an earlier study by different researchers, radiologists were shown chest x-rays with a clavicle (collarbone) missing. Roughly 60% of the radiologists failed to notice this when they were shown x-rays as if for an annual exam.


"It would be a mistake to regard these results as an indictment of radiologists," researchers in the current study write. "As a group, they are highly skilled practitioners of a very demanding class of visual search tasks....[E]ven this high level of expertise does not immunize against inherent limitations of human attention and perception."


Certainly true, Lewinski agrees. He points out in addition that while the test the radiologists were involved in was demanding, "it was not life-threatening for the participants themselves. The level of inattentional blindness can be expected to be even greater among LEOs who are involved in unexpected, rapidly evolving, uncertain, and unpredictable threats to their very existence."


A full report on the new study, titled "The invisible gorilla strikes again: Sustained inattentional blindness in expert observers," will be published in the journal Psychological Services. The authors are Trafton Drew, Melissa Vo, and Jeremy Wolfe.


[Our thanks to Force Science staffer Jennifer Dysterheft for her assistance in reporting on this study.]


II. FS instructor offers insights into chief's comments on officer suicides


You may recall the story that made national news not long ago, regarding a chief who spoke critically of officers on his department who had committed suicide. Of 120 sworn on his agency, three had killed themselves in recent months.


While some observers felt the stress of the job had played a role, the chief declared otherwise. As originally reported in the Chicago Tribune, he emailed his department that "these suicides were about personal choices, selfishness, and weakness."


Criticism fell on the chief like acid rain. One police psychologist and expert on stress management was quoted by a Tribune reporter as asking: "What [officer] in his right mind would seek mental health treatment knowing that the person in command has already shown them it's a signal of weakness and selfishness?"


The widow of one of the suicides, whose 43-year-old husband hanged himself, agreed that he wouldn't have felt comfortable seeking help. "He would have said, 'If I were ever to go to counseling or seek help, people would think I was crazy, and they wouldn't think I could do my job and they wouldn't respect me.' "


While not condoning the chief's sentiment, Force Science instructor Dr. Alexis Artwohl, a former police psychologist, offers some insightful speculation about the context surrounding it.


"Suicide is a complex mental health problem, still not fully understood. Although any stressor could be a precipitant in an already vulnerable individual, it's unlikely that work stress alone would cause someone to commit suicide." Artwohl told Force Science News. "One of tragedies of suicide is how especially devastating it is to the survivors, individually and organizationally.


"In addition to the usual grief of losing someone you know, it's common to have a complex welter of emotions, including confusion, guilt, remorse, and anger at the person for taking their own life. It would be understandable if the chief was experiencing all of those, plus being concerned over his department being blamed for 'work stress' making the officers take their lives. It's one of the worst ways to lose someone.


"Still, no one commits suicide or has other mental health problems just because of 'weakness or selfishness.' Officers need to be compassionately encouraged to acknowledge their emotional problems and get help. This incident is a compelling reminder for all command staff that officers should be assured that if they seek help, they will be confidentially referred to qualified mental providers who will also keep the sessions confidential within the usual legal and ethical guidelines that would apply to any patient."


Quoting other psychologists and mental health advocates, the Tribune noted that "chiefs have a key role in encouraging mental wellness, because their attitudes can influence whether officers get help or suffer in secret."


The chief, meanwhile, says he sent the email when he was "going through an anger stage of grieving after attending the third funeral and giving the man's badge to his daughter." He said he plans to use "every resource available" to develop suicide awareness and prevention programs for the department.


III. Launch date set for special public lectures on LE research


The first of an annual series of special public presentations on groundbreaking law enforcement-related research is set for Apr. 12 at Minnesota State University in Mankato.


The free series, called the Lewinski Lectures, is being launched by the university to honor Dr. Bill Lewinski, who retired from the faculty of MSU's law enforcement department in 2010 after 28 years of service to devote full time to the Force Science Institute.


Lewinski himself will kick off the Lectures with an hour's program on how findings by the Institute can impact police training and use-of-force investigations. Particular emphasis will be given to a new model for training in decision-making under the stress of life-threatening situations, Lewinski told Force Science News.


In future years, the series will feature other individuals who are conducting exceptional research and training in criminal justice.


For exact details on the time and location of Lewinski's lecture please e-mail your full contact information to: His talk will be recorded and is expected to be posted on YouTube as a means of educating a broad audience of police professionals and civilians in critical but poorly understood aspects of officer-involved shootings and other force encounters.


© 2017 Force Science Institute Ltd.