{"id":516105,"date":"2010-04-05T10:00:48","date_gmt":"2010-04-05T14:00:48","guid":{"rendered":"http:\/\/blogs.discovermagazine.com\/notrocketscience\/?p=1248"},"modified":"2010-04-05T10:00:48","modified_gmt":"2010-04-05T14:00:48","slug":"photos-of-sneezing-can-put-our-immune-systems-on-red-alert-not-exactly-rocket-science","status":"publish","type":"post","link":"https:\/\/mereja.media\/index\/516105","title":{"rendered":"Photos of sneezing can put our immune systems on red alert | Not Exactly Rocket Science"},"content":{"rendered":"

\"NHS_poster\"Take a look at this poster. British people will probably be familiar with it already. For everyone else, it was released last year by our National Health Service when fears of a flu pandemic were at their height. When we see images of diseases and their symptoms, we typically feel disgust and repulsion. But unbeknownst to us, our immune systems have started reacting too.<\/p>\n

In a small but compelling study, Mark Schaller<\/a> from the University of British Columbia found that people who see images of sneezes and other signs of disease mount a stronger immune response to later infections than people who see unrelated images. This is the first evidence that the mere sight <\/em>of a possible infection, even through a photograph, can set our bodies\u2019 defences on high alert.<\/p>\n

Previously, Schaller has suggested that the visual signs of disease trigger a variety of psychological tics that reduce our chances of infection. A disgusted reaction fulfils this role by making us less likely to approach potential sources of contagion. Last year, another group showed that a sneezing passer-by<\/a> can make people more worried about completely unrelated threats, like heart attacks, crime and accidents. To Schaller, these reactions are all part of our \u201cbehavioural immune system\u201d \u2013 our means of preventing infections by changing our behaviour.<\/p>\n

But his latest study suggests that images of sickness can prime our actual <\/em>immune systems too. He recruited 28 volunteers, split them into two groups, and showed them two slide shows. The first slides were just shots of furniture. The second set showed either signs of infectious diseases, such as pox, skin lesions or sneezing, or images of people brandishing guns, mostly aimed directly at the viewers.<\/p>\n

<\/span>Schaller collected blood samples from the volunteers before and after each slide show, and mixed them with molecules that give away the presence of marauding bacteria. He wanted to see how strongly the white cells in the blood would respond to these danger signs. To do that, he measured the concentrations of a protein called interleukin-6<\/a> (IL-6), which while blood cells secrete in response to infections, burns or wounds. The more IL-6 there is, the stronger the body\u2019s immune reaction.<\/p>\n

He found that the white blood cells responded much more aggressively to the bacterial molecules after the volunteers saw the symptom slides. The furniture images didn\u2019t change the amount of IL-6 in the recruits\u2019 blood samples, the gun images raised these levels by 7%, but the disease images increased them by 24%.<\/p>\n

\"Guns_disease\"This suggests that the immune system reacts with extra vigour after its owner sees an image specifically related to disease, rather than one that invokes a general sense of threat or danger. Indeed, when questioned later, both groups reported the same levels of stress and fear even though only one of them manifested an actual physical reaction.<\/p>\n

There is one caveat \u2013 the people who saw the gun images had higher levels of IL-6 in their blood samples before <\/em>the experiment than those who saw the disease images. The difference wasn\u2019t statistically significant, but it could suggest that Schaller didn\u2019t split his groups randomly enough. He acknowledges this possibility but he says that the two groups weren\u2019t any different in terms of their personality traits or how worried they were about disease. Nonetheless, this is an issue that could easily be addressed by doing a larger follow-up study using more volunteers.<\/p>\n

For the moment, the effect is certainly plausible. From an evolutionary point of view, putting our immune systems on alert if we see signs of infection might reduce the odds of contracting a disease without having to distance ourselves from our social groups. However, Schaller suggests that in modern times, such responses might be counterproductive. An image of a sneeze is clearly not a sign that disease is imminent, and priming our immune systems to a non-existent threat isn\u2019t the best use of our valuable energy.<\/p>\n

Reference: <\/strong>Psychological Science http:\/\/dx.doi.org\/10.1177\/0956797610368064<\/a><\/p>\n

More on immune systems: <\/strong><\/p>\n