In their classic book News That Matters: Television and American Opinion, Shanto Iyengar and Donald R. Kinder document “a series of sophisticated and innovative experiments that unobtrusively altered the order and emphasis of news stories in selected television broadcasts” and showed that “issues that receive extended coverage in the national news become more important to viewers, while those that are ignored lose credibility. Moreover, those issues that are prominent in the news stream continue to loom more heavily as criteria for evaluating the president and for choosing between political candidates.”
The ultimate takeaway of the book is that current events act as a powerful form of priming, meaning that what we see in the news unconsciously influences our decision-making criteria. If talk of the economy looms large, for example, people will be primed to think more economically. Similarly, if social justice is the talk of the day, people will be more likely to consider this when making decisions.
It’s important for speakers to understand these effects because if they do, they can use them to good effect. By considering how your audience has recently been primed by recent events in the world (as well as events in their more immediate environment), you can more effectively craft your message to appeal to their specific decision-making criteria, increasing your chances of speaking success.