Summer's here and it won't be long before school -aged kids across America start complaining that they're tired of riding their bikes, playing at the park, swimming in the pool ..... and all the other awesome activities their parents hoped would keep them entertained for the next 10 weeks.

Such rapid—onset boredom could indicate that the kids have amazing powers of recall. Because a new study shows that the better your short—term memory is, the faster you feel sated and decide you've had enough. The findings appear in the Journal of Consumer Research. “Though satiation can be physical, like when you feel full after eating too much, we were interested in the psychological side of satiation. Like when you're just tired of something.” Noelle Nelson, assistant professor of marketing and consumer behavior at the University of Kansas School of Business. She and her colleague Joseph Redden at the University of Minnesota tried to think outside the lunch box. “Something that was interesting to me is that some people get tired of same things at very different rates. So if you think about pop songs on the radio, some people must still be enjoying them and requesting them even after hearing them a lot. But a lot of other people are really sick of those same songs.” The difference might have to do with memories of past consumption. For example, studies show that people push away from the dinner table sooner when they're asked to describe in detail what they ate earlier for lunch.

The findings suggest that marketers could use our desire for their products by figuring out ways to distract(使分心)us and keep us from fully remembering our experiences. We could also trick ourselves into eating less junk food by immersing(使浸没)ourselves in the memory of a previous snack. As for kids easily bored, just tell them to be fogged(模糊的)about it—it might help them have more fun.

LAS VEGAS—It was different in the light of day.

There was no ‘pop, pop, pop’ of gunfire, no screams. Just a quiet lot of cars abandoned by those, like Kassidy Owen, who escaped with their lives.

“It’s strange to hear the silence,” Owen said, “because all I remember was the noise.”

The 22-year-old was one of dozens of concertgoers who returned to the scene of the Route 91 Harvest festival on Wednesday morning to fetch the vehicles they left behind as they fled from a gunman raining down bullets from high above in the tower of the Mandalay Bay Resort and Casino across the street.

Survivors of the deadly mass shooting in Las Vegas on Sunday needed their cars to move on with their lives—to get back to work, to school, home. It was the first time they were returning to a scene that would forever change them, when joy and celebration and music turned into killing and horror.

Before they could move forward, they had to go back to the place where they thought they were going to die.

Owen had run to her car to hide and had tried to drive away, but she couldn’t. People were running, bodies dropped to the ground, and cars bottlenecked in the parking lot. During a brief pause after more than 10 minutes of gunfire, she worried the lights of her SUV made everyone inside a shining target.

“They’re shooting again!” her best friend’s brother screamed. “Turn off the car!”

That’s when she got out and fled.

“I just remember shutting the door and running.” Owen said.

Now, nearly three days later, she was back, sitting in the driver’s seat of her SUV. Her eyes were swollen and red. This was a long way from over.

“You just keep hearing the gunshots in your head,” Owen said.

The American Academy of Pediatrics (AAP) (儿科学) just released its updated guidelines for children’s media use.

The recommendations reflect what all parents know: children need less screen time, which indicates that they desperately need more free time to develop their imagination, a sense of wonder and discover their passion and purpose.

Our children are over-stimulated, over-scheduled and under pressure to perform academically and beyond school. This weakens their ability to build creative thinking skills essential to self-discovery. Creativity occurs when kids have time for curiosity and exploration. With children spending up to eight hours a day on media devices and additional hours engaging in scheduled activities, opportunities for growth disappear.

What we are not so sure about is how to get our kids to want the free, screenless time which we know will benefit them. It may sound counter-intuitive (违背直觉的) but today’s kids need coaching to experience and discover the benefits of free time.

What came to parents easily a few decades ago has become a challenge for our generation. It’s not that yesterday’s parents knew more about child development; they simply had fewer choices. Boredom and relaxation were an inescapable part of daily life. Today, they mean, “I’m a bad parent and not doing enough to get my kid ahead.”

Recently, I had an eye-opening revelation while watching my 11-year-old daughter play in a softball game. I have six children and have attended dozens of such game. I know the drill—or thought I did. Families settled in for the day with lawn chairs, cold drinks and cousins. These brothers and sisters would gradually chat with each other. Games of catch and hide-and-seek began, and friendships were formed then. At crucial moments, the newfound friends turned their attention to the field to cheer on their teams.

But that wasn’t happening. Though there were at least 15 children by the sidelines (球场边线), I didn’t hear any of them. They sat in silence using their individual tablets (平板电脑). Even with the score tied in the final inning (垒球比赛的一局), not a single child watched the game or spoke to each other. The situation was strange and revealing: Kids have more planned activities and passive entertainment at their fingertips than ever before, but less free time to dream, imagine and focus on what they truly love.

I understand that making time for “nothing” is difficult in a world where we are constantly worried our kids will fall behind if they aren’t good at academics. But I refuse to sit back and watch this loss of childhood. We are taking back childhood. Imagination needs time and space to blossom.

If your kids are like mine, asking them to imagine will at the beginning be difficult. That’s because they haven’t developed the skills and muscle memory to make it second nature. I hope the AAP guidelines prompt all of us to set needed screen time limits for our children. Personally, I am practicing strategies to “develop imagination” in my children. Imagination, like a sport, requires practice, training, motivational speeches, rewards and extreme patience.