Like it or love it, social media is a major part of life. Clicking on a thumbs-up or a heart icon (图标) is an easy way to stay in touch. Whether you’re on Facebook, what’s App or Twitter, the way, of keeping in touch is no longer face to face, but instead screen to screen, highlighted by the fact that more than 1 billion people are using Facebook every day. Social media has become second nature — but what impact is this having on us?

Lauren Sherman and her team, who study the brain at Temple University in Philadeiphia, mixed 20 teens’ photos with 10 other pictures from public Instagram accounts. Then they randomly gave half of the images many likes (between 23 and 45; most had more than 30). They gave the other half no more than 22 likes (most had fewer than 15).

The researchers wanted to find out how the participants’ brains were responding to the different images. While the teens were in a machine, researchers asked them to either like an image or skip to the next one. Teens were much more likely to like images that seemed popular — those that had more than 23 likes, Sherman’s team found. The kids tended to skip pictures with few likes.

As part of the experiment, participants were also shown a range of “neutral” photos showing things like food and friends, and “risky” photos concerning cigarettes and alcohol. When looking at photos showing risky behaviors, such as smoking or drinking — no matter how many likes they had — the brain region linked to cognitive (认知的) control tended to become less active. These kinds of pictures can lower the viewer’s self-control. That means what you like online has the power to influence not just what others like, but even what they do. Viewing pictures like these could make teens let down their guard when it comes to experimenting with drugs and alcohol, Sherman worries.

【小题1】What does the text focus on?

A．The behaviors of teens.

B．The self-control of teens.

C．The influence of social media.

D．The popularity of social media.

【小题2】Which of the following might be included in the experiment?

A．Seventeen images are given 20 likes.

B．Fifteen images are given 25 likes.

C．Fifteen images are given 42 likes.

D．Eight images are given 40 likes.

【小题3】What’s Sherman’s concern about online photos?

A．More likes may be given.

B．Misbehaviors may be encouraged.

C．More risky pictures may be posted.

D．Cognitive control may become less active.

【小题4】What is the author’s purpose in writing the text?

A．To condemn immoral social behaviors.

B．To promote modern social media.

C．To explain the brain system.

D．To introduce a new research.