Playing the computer game Tetris after a horrific experience can act like a “cognitive antibiotic” by reducing the harrowing flashbacks that haunt people with post-traumatic stress disorder (PTSD).
Flashbacks are a hallmark of PTSD, especially among soldiers who have witnessed terrible events in combat. Soldiers with PTSD are more likely to be disabled or to die from accident or illness than those who do not, even decades later. “It’s the kind of memory that pops back when you don’t want it to,” says Emily Holmes, a clinical psychology researcher at the University of Oxford.
Last year Holmes showed that if volunteers played Tetris for half an hour after looking at graphic images of injuries, they had fewer unwanted memories of the images as a result. But it wasn’t clear whether the game simply acted as a distraction or the effect was common to all computer games, she says.
Holmes’s latest research suggests that this effect may only occur with visuospatial games, of which Tetris is the classic example.
In her latest experiments, Holmes again showed volunteers the traumatic images and then compared the number of flashbacks experienced by Tetris players with the corresponding number among volunteers who had played a general knowledge “pub quiz” game; a control group had no computer game to play. She found not only that Tetris players seemed to have almost half as many flashbacks as normal, but that those playing the general knowledge game experienced slightly more than normal. “It made it worse in the short term,” she says.
What’s more, the beneficial effects of Tetris remain even when played 4 hours after the trauma, says Holmes. This suggests that the game is not just a distraction, but is interfering with the mechanisms that form the intrusive memories, she says.
Flashbacks are caused when there is an imbalance between our perceptual experience – what we see, hear, taste and smell – and the conceptual experience that allows us to comprehend and make sense of it all. During a trauma, such as a high-speed car crash, the perceptual experience can be emphasised over the conceptual, says Holmes. This can make it difficult to remember the event as a coherent story, instead imprinting it in memory as a raw set of perceptual experiences: the flash of headlights and the grinding of metal, say. It is this kind of memory that can cause great distress to a victim by repeatedly popping up, Holmes says.
But it can take up to six hours after a trauma for the brain to create these intrusive memories from these events, leaving a window of opportunity to prevent them from forming. According to Holmes the Tetris effect occurs because the visuospatial work required to play the game places an additional burden on the perceptual systems within the brain and so interfere with this memory-forming process.
“It’s not wiping out the memory – it’s just taking the edge off its intrusiveness,” she says. In contrast, the verbal game appears to interfere with our conceptual experience, making it difficult to make sense of the perceptual memories and so exacerbating the flashbacks.
Journal reference: PLoS One, DOI: 10.1371/journal.pone.0013706
Photo by Aldo Gonzalez