"Maybe this was because it was in an area that so many of us had visited over the last few years, or because the attack targeted young people having a good time, but it had a major impact.”Because of the relentless news cycle, now it feels like terrorism has become a topic of constant national conversation in the UK, she said. This means that, “Now when news comes through, on Guardian notifications, or Twitter or whatever, yes it’s awful to read, it’s horrific, but it’s not shocking or unexpected," she said.“We should go to bed uneasy and shocked after each new attack, but the power of the images, the headlines, and the news of a terrorist attack, is less.”No research appears to have been conducted yet into the specific effects of the most recent wave of terrorism in northern Europe, but existing theories of the impact of the media on human behaviour suggest that increased and consistent coverage of violence may, indeed, have a numbing effect.“One concern about increased and consistent coverage of violence in the media is that we may become desensitised to the violence,” Dr Morgan Tear, research officer in the Department of Psychological and Behavioural Science at the London School of Economics, told Refinery29. “In the scientific literature, desensitisation is a process whereby repeated exposure to a distressing stimulus diminishes the emotional response to the stimulus.”When it comes to violence in the media, desensitisation theory suggests that when we’re repeatedly exposed to graphic violence in news reports for prolonged periods, the psychological impact may decrease until it no longer affects us and we become emotionally numb. In other words: We get used to bad news.Most research in this area focuses on using repeated exposure to reduce the impact of phobias, and less is understood about the psychological effects of violence in the media, said Dr Tear.However, studies show that some people experience symptoms of post-traumatic stress disorder (PTSD) linked to exposure to violent news coverage. One of these symptoms is “emotional numbing” – dealing with feelings by trying not to feel anything – which sounds a lot like desensitisation, and dulled responses to others and the outside world. Researchers at the University of Bradford showed that viewing violent news on social media can have this effect. They put images and information about violent events, including the 9/11 attacks, school shootings and suicide bombings, in front of 189 participants. Of those, 22% were “significantly affected” by what they saw – despite them having no previous trauma, not being present at the traumatic events and having only watched them via social media. Furthermore, those who viewed violent events more often were more affected.Dr Pam Ramsden, from the research team, said the fact that nearly a quarter of participants scored high on clinical measures of PTSD was “quite worrying” . “With increased access to social media and the internet via tablets and smartphones, we need to ensure that people are aware of the risks of viewing these images and that appropriate support is available for those who need it,” she added.Similarly, in another study , of more than 2,000 U.S. adults after 9/11, the more time people spent watching TV coverage of the attacks, the more likely they were to experience symptoms of post-trauma related stress.It might be that some of us are choosing to become desensitised on purpose – deciding to not engage with the news as often as we once did to avoid becoming upset. For many of us, especially those prone to worrying, the alternative – becoming so engrossed and emotional over each atrocity so that you end up living in fear – isn’t really an option.