科学家给出了一些理论，其中一种理论认为：当你首次有某种体验时，比如第一次亲吻，会在你的记忆中会留下更多细节信息，如嘴唇的接触，兴奋，味道，气味等等——此时此刻的各种细节对你来说都是全新的，年轻时我们有许多第一次需要记住。
大脑记忆编码的清单是如此密集，当我们回忆过去的美好时刻时候，总会觉得它们仿佛发生在很遥远的过去，发出时间过得真快的感慨。这其实是一种错觉，与大脑的结构有关，因为第一次记忆的细节丰富，而之后发生的相同事情留下的细节很少。过去和现在的时间流逝其实是一样的。
Yes, we all get older. But now, getting older has become a video fetish; all kinds of people take pictures of themselves every day for six, seven, eight years and then blend the images together into a ... well, if you've missed the Web craze, Homer Simpson's "Every Day" is a perfect catcher-upper.
Not only can you see Homer switching jobs (cavalryman, Indian, king, infantryman, fisherman, fireman), you watch his body grow, swell, swag. As with all things Simpson, the physical changes are dramatic.
But what these videos don't show are the psychological changes, and one of the most universal changes is that as humans age, they change the way they feel about time.
Faster And Faster And Faster
As people get older, "they just have this sense, this feeling that time is going faster than they are," says Warren Meck, a psychology professor at Duke University.
This seems to be true across cultures, across time, all over the world.
No one is sure where this feeling comes from.
Scientists have theories, of course, and one of them is that when you experience something for the very first time, more details, more information gets stored in your memory. Think about your first kiss.
Neuroscientist David Eagleman of Baylor College of Medicine says that since the touch of the lips, the excitement, the taste, the smell — everything about this moment is novel — you aren't embroidering a bank of previous experiences, you are starting fresh.
Have you noticed, he says, that when you recall your first kisses, early birthdays, your earliest summer vacations, they seem to be in slow motion? "I know when I look back on a childhood summer, it seems to have lasted forever," he says.
That's because when it's the "first", there are so many things to remember. The list of encoded memories is so dense, reading them back gives you a feeling that they must have taken forever. But that's an illusion. "It's a construction of the brain," says Eagleman. "The more memory you have of something, you think, 'Wow, that really took a long time!'
"Of course, you can see this in everyday life," says Eagleman, "when you drive to your new workplace for the first time and it seems to take a really long time to get there. But when you drive back and forth to your work every day after that, it takes no time at all, because you're not really writing it down anymore. There's nothing novel about it."
That may be because the brain records new experiences — especially novel and exciting experiences — differently. This is even measurable. Eagleman's lab has found that brains use more energy to represent a memory when the memory is novel.
So, first memories are dense. The routines of later life are sketchy. The past wasn't really slower than the present. It just feels that way.
There are all kinds of arguments one could have with this theory, but before we poke it, we want you to feel it.
Here's a celebration of dense early memories from a very recently departed (not to heaven, just back to California) intern at NPR, Maggie Starbard. With a bunch of friends (Caitlin Fitch, Mark Turner and Mike Eckelkamp), Maggie decided to dwell on a lazy beach where kids are collecting dense memories by the truckload:
Now for the pokes. Who said that novel experiences belong exclusively to the young?
Older people have novel experiences — lots of them. Some of us have crazier middle ages than youths. We fall in love, out of love. Then our parenting years are filled with watching our babies' first thises, first thats. Retired people travel — if they can afford to — to duplicate some of those rushes of novel experiences.
Yes, it's true, the youngest years are chock full of novelty, but Duke's Warren Meck points out that when you hit your 60s and 70s, and time is beginning to run out, experiences get more precious and once again you remember all the details.
So take this "novelty" explanation for why time moves faster as you age and weigh it as you will.
Other theories may prove more satisfying.
Professors Meck and Eagleman explore a number of them on ourAll Things Consideredbroadcast. If you wish to hear the "Aging Brain" theory of why time goes faster, or the "How Long Have You Been Alive?" explanation, they await you at the top of this page, where the button says "Listen."
本文中文来源为：solidot本文英文来源为：wbur
