Teens’ behavior is difficult to change because they are very sensitive to anything they regard as a danger to their autonomy(自主). And, as many parents know, many problematic behaviors come about because teens aren’t motivated by thinking about long-term results and they won’t be willing to listen when you point out they are doing silly things.

Among other things, these attitudes make it hard to make teens eat healthily. However, a recent study published in PNAS shows that it’s possible to use teens’ social values to motivate them to accept a better diet. The method makes sense, considering that teens are known to place a high value on their social environments.

The study showed teens’ tendency to develop social justice(公正) goals during their adolescent(青春期) years — they often do this as a reaction to authority figures(权威人物) whom they regard as unjust. The researchers designed an intervention(干预) to show the teens how high-calorie/low-nutritional value foods are misleadingly marketed as healthy choices. They also educated teens about poor people and young children were often misled into eating the unhealthiest foods. The intervention framed healthy eating as a way of “sticking it to the man”.

The researchers found that teens who received the intervention were less likely to make unhealthy choices than teens who didn’t. After the intervention, they were more likely to pick snacks like carrots or fruit than they were to pick cookies or chips. They were also less likely to choose sugary drinks and food with low nutritional value.

This study shows that it isn’t necessary to cause long-term results in order to encourage teens to make healthier choices. Instead, educating teens about the symbolic meaning behind the choices that they make seems to be enough to motivate them to make better choices.

This finding has a lot of practical value. Public health professionals are often looking for ways to encourage people to make better food choices, and many food-based habits are developed in childhood and adolescence. If more young people are motivated to make good food choices, those decisions are likely to keep into adulthood and have a lifelong positive effect.

【小题1】According to the passage, how does the study help teens have a better diet?

A．By showing teens the long-term effect.

B．By learning about teens’ food-based habits.

C．By guiding teens to have a positive attitude.

D．By using teens’ social values to motivate them.

【小题2】What do you know about the study from the passage?

A．Teens are willing to listen to the scientists.

B．Teens’ decisions are likely to have an effect.

C．Teens learn about the influences of the study.

D．The intervention helps teens make healthy choices.

【小题3】The writer probably agrees that ________.

A．teens always choose sugary drinks and food

B．making healthy choices has a positive effect

C．it’s easy to develop teens’ social justice goals

D．it’s necessary to have a lot of practical value

【小题4】What is the writer’s main purpose in writing this passage?

A．To guide people to improve teens’ diet.

B．To introduce the study about motivation.

C．To explain why the teens are very sensitive.

D．To discuss what is the best choice for teens.