How Just a Loud Noise Can Ruin Someone’s Day
Have you ever been focused on something, such as a homework assignment or a TV show, and been suddenly startled by a loud noise? If so, you probably quickly focused on the noise and its source, then returned to the task at hand. This is an example of attentional capture. Attentional capture is the involuntary redirection of attention to an environmental cue, with the purpose of surviving potential predators or dangers. Although we aren’t usually in danger, cues such as loud noises, flashes, or quick movements temporarily grab our attention from our current task. Once we label the potential danger as being safe, we easily return our focus back to our original task. However, not everyone can return to their previous task so easily.
As the war in Iraq and Afghanistan slowly comes to an end, the military and the military families have begun to focus on the longer lasting effects of war on the men and women that served overseas. Many of the injuries sustained in the Middle East have been physical, and are being treated as such by doctors and nurses. However, it is estimated that 10-20% of the remaining men and women suffer from a psychiatric injury, called Post-Traumatic Stress Disorder.
Post-Traumatic Stress Disorder, or PTSD, is a disorder that originates from experiencing or witnessing a life-threatening event. Its symptoms include nightmares, feeling detached and numb, becoming easily aggravated, having an exaggerated startle response, and re-experiencing the event through flashbacks. A major issue with veterans in life after war is that they seem to not be able to focus on the task at hand, and that they can’t control their emotional reactions to daily life events. It is possible that attentional capture has an effect on these problems. That is, veterans with PTSD could be more affected by a simple environmental cue such as a knock on the door, which could set off the emotional trauma ingrained in their minds, keeping them from following a normal daily routine.
In order to test the hypothesis that attentional capture has a major impact on veterans with PTSD, Olatunji, Armstrong, McHugo and Zald created an attention blink task. The study, which you can read here, looks at the differences between those with PTSD and those without PTSD, and how their attention differs with threatening cues. Olatunji et al. examined 20 veterans diagnosed with PTSD, 16 veterans who did not have the symptoms of PTSD, and 22 neutral nonveterans to act as a control group. It is important to note that the 16 veterans without PTSD did in fact experience a life-threatening event, but did not show any symptoms of long lasting effects.
The attentional blink task examined the way the three groups reacted to a series of images. These images consisted of filler images, distractor images, and target images. The filler images were simply upright photos of landscapes and architecture, meant to fill in the gaps between distractor and target images. The distractor images were either combat-related threatening photos (soldiers in combat), disgusting images (feces), happy images (baby animals) or neutral images (household objects). The target images were landscape or architecture photos, but rotated 90 degrees to the left or the right.
Seventeen of these photos were flashed one after another to the participants, each image lasting 100ms long. The target images were flashed 200ms, 400ms, 600ms, or 800ms after the distractor images. After the 17 photos were flashed, the participants were asked to determine whether they saw the target image (the image rotated to the left or right), and if so, what direction it was rotated. Olatunji et al. were interested in whether the combat-related distractors would uniquely impact the veterans with PTSD when trying to see the rotated image, and if so, how long the effects would last. If they found that to be true, it would suggest that veterans with PTSD have their attention captured by the threatening image, with an inability to break free of that capture.
Olatunji et al. found that when the distractor image was combat-related, veterans with PTSD had a lower detection rate of the target image and lower accuracy in determining the rotation. However, the veterans without PTSD and the nonveterans both scored a similar, higher score. This shows that the combat-related image only negatively impacted the ability for veterans with PTSD to pay attention to the task at hand. Even though the veterans without PTSD had experienced a life-threatening event, they were not negatively impacted by the threatening image. This shows that people with PTSD have a harder time paying attention to a task when previously exposed to any level of threat.
Olatunji et al. found that the other three distractor images, the disgusting, happy, and neutral images, did not differentiate the veterans with PTSD from those without PTSD. This shows that veterans with PTSD are not affected by everyday cues, such as an image of feces, but rather only life threatening cues.
Lastly, Olatunji et al. were interested in how long the effects of the combat-related images would last on veterans with PTSD. As stated before, the target image was flashed either 200ms, 400ms, 600ms, or 800ms after the distractor image. The veterans with PTSD were only negatively impacted when the target image was 200ms, 400ms, and 600ms after the combat-related image. If the target image was flashed 800ms after the combat-related image, the veterans with PTSD had the same accuracy as the veterans without PTSD and the nonveterans. This shows that after about 600ms, the effects of the threatening image have worn off. It also shows that the combat-related image negatively impacts people with PTSD for up to 6 images, which is a relatively long time in a test only lasting 17 images.
We can learn a lot about why veterans with PTSD act the way that they do. Olatunji et al.’s study shows that those with PTSD have a harder time redirecting their automatic attention responses from an attention-capturing threat back to their task at hand. For example, if a veteran with PTSD hears a loud bang from something falling, he or she will have a harder time determining that the area is safe, and that he or she can return to normal daily activities. Furthermore, Olatunji et al. found that these effects can last for 600ms, a relatively long time for a small detection task. This shows that veterans with PTSD have a harder time controlling their automatic reactions to external cues, and have a harder time disengaging from a threat. This can explain why they often have flashbacks, and often escalate situations that seem minimal to everyone else.
This study is beneficial in the more general sense because it looks into a possible way to better detect PTSD. Currently, PTSD is difficult to detect, as veterans must come forward and ask for help, and usually are hesitant to do so. However, if veterans with PTSD score worse on this task when faced with a threatening image than veterans without PTSD, then this could help point doctors in the right direction early. Early detection and treatment is imperative to save the lives of the members of our military.
This study is very important for everyday readers, as we all know someone who has served in a war. If we can understand the things that can negatively impact someone with PTSD, we can help prevent them. Beyond war, car crashes, sexual violence, and domestic violence can all lead to PTSD, as they are life-threatening experiences for everyone involved. Understanding how symptoms can arise from simple cues that reference the original experience can help us work with friends or family that are affected.
Reference:
Olatunji, B. O., Armstrong, T., McHugo, M., & Zald, D. H. (2013). Heightened attentional capture by threat in veterans with PTSD. Journal of Abnormal Psychology, 122(2), 397-405
This is exactly the kind of study that brings up questions about ethical research. Participants suffering from PTSD were shown threatening images of wartime during the experiment, reminding them of their hauntung trauma that is the T is PTSD. Intuitively, this sounds wrong and unethical, and that’s why the balance of what is ethical and what isn’t is so fascinating. The emotional harm on those participants seemed mild, although I can’t say I know for sure, and this research has the practical value of providing a way to identify those who need help. The possible future benefits outweigh the risk during the study.
However, I’m not so sure about the effectiveness of this is a way to identify veterans with cases of PTSD. The two veteran groups used were already known to show symptoms of PTSD or not, and that’s the key point here; they were groups. On average, the people known to be suffering from PTSD were less accurate than the veterans who had lived through a life-threatening experience but showed no symptoms of PTSD. I’m not so sure that would translate to people on an individual basis; there isn’t really a way to administer this to one person and determine mental based on the result. A victim of the disorder could still be vigilant enough to notice that target image, and someone showing no symptoms could be less accurate for other reasons. A glaring issue in this is that the measurement used is the orientation of the target image, which can only be left or right. There’s a 50/50 shot they’d get it right just by guessing, and so someone who’s attention was taken captive by the distractor image could still guess and get the right answer. It doesn’t have to be actively lying, they could really believe they saw it even if they didn’t or they only saw it with reduced attention. The research provides very useful information on how to identify and help these people based on attentional capture, but using this design would not be a good idea.
Why does PTSD affect return from attentional capture? I suppose during wartime if you heard a loud crash or other exogenous cue you would be accustomed to hunting around for other signs of danger before you return to what you were doing. Back home it’s not something we worry about, a loud crash can be an isolated thing, but for a soldier it could mean there is more danger nearby. Maybe that’s what this attentional capture is, an extended period of time to examine the life-threatening stimulus. That doesn’t really make sense though, because all veterans would develop this kind of habit, and taking more time to examine a threat wouldn’t really be a good thing. Most likely what’s happening is that those who have haunting traumatic memories would flashback to their memory at that kind of cue. The extra time spent captured by the image is actually spent dwelling on the memory recalled by the image. The symptoms of PTSD are signs that the person is reliving the event whenever they make a mental connection to it, and so they get put in the mindset they were in during that event, like a particularly horrible flashbulb memory. They way attentional capture happens here is that some sort of trigger draws them away from their task and then they get distracted by their own memories. This happens with everyday memories to everyone, but for a war veteran with PTSD, this would be much more stressful due to the kind of memory. It’s amazing how certain people can live through events like that and be so in control as to not show signs of PTSD. That is not to say they come away unscathed, as addressed in the powerful statement made in that comic panel.