让孩子幸福的圣诞谎言

编辑:给力英语新闻 更新:2017年12月4日 作者:凯利·兰伯特(By KELLY LAMBERT)

我永远忘不了12年前的那一天，那是在12月，我有惊无险地化解了一场家庭假日危机。当天上午我还在办公室编写一本神经科学教材，同时期待着下班后见到我的两个女儿——3岁的斯凯拉(Skylar)和7岁的劳拉(Lara)。但我下班后一进家门，丈夫就告诉了一个让我阵脚大乱的消息。姑娘们一直在阁楼里翻箱倒柜。而我本以为把圣诞礼物藏在那里会万无一失。还有一周多才到圣诞节，她们就已经看到了圣诞礼物了！

不知道当时是怎么回事，但是我大脑里某个母性脑叶突然被激活，把自己变成了圣诞老人的法律顾问。我跟女儿们说，“我就担心这种事会发生！”然后解释说，圣诞老人已经联系了所有想要大件礼物的孩子的家长，告诉他们自己背部有疾。圣诞老人的太太坚持要圣诞老人提前把一些笨重的礼物通过UPS快递出去，那么在圣诞前夜送礼物就没那么痛苦了。

但是这么做有一个前提条件，我必须签一个合同，承诺无论如何，在圣诞老人在圣诞前夜把礼物送出去之前，我绝不能让孩子们先看到这些礼物。如果孩子们看到了礼物，这些礼物就必须还给圣诞老人。

“不！不！”女儿们哭喊道，“我们……只看到了其中的几个，连它们是什么都没记住。”

我告诉她们，虽然我可能违反了约定，但我决定只把她们看到的几个还回去，留下她们没看的礼物。在严肃的协商之后，我们都认为这是一个好主意。于是我深吸了一口气，继续装饰我的家。

我不仅是一个母亲，还是一名行为神经学家、一个教授，而且总的来说是一个性格严肃、注重事实的人。那么，我刚刚到底做了什么？我为什么要编出这个不可信的故事，不顾一切地想要保护我的女儿们对圣诞老人的幻想，而不是利用这个机会来告诉她们真相？

尽管表面上看，我似乎是把我所受的科学教育都抛诸脑后了，但事实远非如此。

尽管儿童生来就有完整的860亿个脑细胞或神经元，但在幼年时期，这些神经元之间的联系相对稀疏。随着大脑的发育——神经元之间形成了越来越多的微线延伸，在微小的沟回里出现了神经化学物质——孩子们慢慢学到了客观世界的法则，了解了虚构和非虚构的区别。最终，他们知道了驯鹿不会飞，圣诞老人也不会在一天晚上来到每个小朋友家，即使他真的来了，也不可能吃掉所有饼干。随着反映真实世界的成熟的神经回路变得强大起来，相信幻想的感觉就会慢慢消失。

不过，幸运的是，我们不会彻底失去原先的这些思维方式，因为大脑似乎拥有一种神经时间旅行的机制。我所说的神经时间旅行机制并不单指在成年之后拥有曾经相信过圣诞老人的温暖记忆。圣路易斯华盛顿大学(Washington University in St. Louis)研究记忆的教授帕斯卡尔·博耶尔(Pascal Boyer)指出，所谓的情节记忆(episodic memories)与心理时间之旅(MTT)记忆不同——前者包括第一次坐在圣诞老人的膝盖上，或者某一年暴风雪导致停电的情景；后者更接近于重新经历记忆中的某个事件。博耶尔教授说，神经成像方面的证据显示，当特定事件被回忆起来的时候，大脑的情感区域，以及本能的反应都会被激活——比如看到熟悉的情景、闻到熟悉的味道、听到熟悉的声音，触发起过去的回忆时。这样，你就会重新经历过去体验过的感觉，可以认为这种回忆既包括整个身体的记忆，也包括大脑的记忆。

这种记忆可能会令人痛苦，比如对于那些患有创伤后应激障碍(PTSD)的人。它也可以存在于我们的日常生活。想象一下，一个人先吃了一个辣味热狗，接着去坐过山车，于是感觉恶心想吐。在之后的很多年里，可能每当他看见辣味热狗都会感到恶心——即使他清楚地知道，导致他不舒服的是过山车的运动。如果大脑认为某件事很重要，很难把条件反射式的反应抹除。谢天谢地，这也适用于快乐的记忆。

心理时间之旅的概念告诉我，努力让女儿们相信圣诞老人的存在是正确的。每年，我都让她们的大脑增加一次关于圣诞节的记忆，她们也会越来越容易地重新获得这种感受。

在我自己的童年，那么多年里我都会背诵着“圣诞节前夜快要到来”(’Twas the Night Before Christmas)、闻着冷杉树的气味，然后满怀期待地入睡——那种期待，仿佛是可卡因成瘾者在盼望着吸到一生中最过瘾的一次。这些记忆已经成为我的大脑中关于假日的永恒记忆的一部分。

（神经科学无意间还证实了圣诞节蕴含的更多智慧：对假日的期待可以像收到真正的礼物一样令人兴奋。啮齿目动物的研究显示，从神经学角度来看，吸毒成瘾的大鼠在期待得到可卡因之时，就能够感受到快感，即使它们没有真的在吸食可卡因。）

如今，我是一个如此的务实人，以至于我的女儿们都开玩笑地叫我“骨头姐”(Bones)——Fox电视台的《识骨寻踪》里那个清心寡欲、社交能力低下的法医人类学家。即便如此，因为我在大脑还能毫不费力地想象出驯鹿飞翔的景象时，强化了节日的记忆，所以每当我遇到到节日的景象、气味和声音时，仍然能产生圣诞节的神奇感受。就像是巴甫洛夫(Pavlov)的流口水的狗，我的“圣诞情绪”是条件反射的结果，这些条件反射在我大脑的不同区域受到了巩固，适当的景象和气息的刺激，仍然能让我感到节日的兴奋。

因此，尽管我讲出那个圣诞老人后背不好的蹩脚故事时，正处在妈妈模式，而不是神经科学家的模式，但神经科学研究证实，努力确保我的女儿有一个唤起假日情感的途径，对她们成年后的大脑是有好处的。我相信，这和儿童时期注射疫苗一样重要——它适用于所有孩子，无论他们记住的是圣诞节，还是别的什么庆典或传统。长大成人后，即使我不在她们身边了，圣诞老人的形象也会让我的女儿们，再一次像孩子那样看待这个世界，哪怕只是稍纵即逝的些许瞬间。

凯利·兰伯特(Kelly Lambert)是伦道夫·梅肯学院(Randolph Macon College)的一名神经学教授，著有《实验室小白鼠的编年史：一位神经学家从地球上最成功的哺乳动物那里发现的生命奥秘》。
翻译：王湛

Santa on the Brain

I’LL never forget that December day 12 years ago, and the family holiday crisis I so narrowly averted. I had spent the morning at my office writing a neuroscience textbook, and was looking forward to returning home to spend some time with my 3- and 7-year-old daughters, Skylar and Lara. But the news I received from my husband as I walked through the door was devastating. The girls had been exploring in the attic — a space I’d thought was the perfect hiding place for Santa’s gifts. It was more than a week before Christmas and they had just seen their presents!

I’m not sure where it came from but some maternal lobe in my brain immediately became activated, and I morphed into Santa’s legal counsel. “I was afraid this would happen!” I told the girls. I went on to explain that Santa had contacted all the parents whose kids were expecting bulky gifts that year and shared that he was having back problems. Mrs. Claus had insisted that Santa send some of those gifts ahead of time via U.P.S. so he wouldn’t be in so much pain delivering them on Christmas Eve.

But there was a condition to this agreement. I had to sign a contract stating that I would not, under any circumstances, let my children see the gifts before Santa had a chance to set them out on Christmas Eve. If the children saw the gifts, they would have to be sent back.

“NO! NO!” cried my girls. “We ... we only saw a few of them. We don’t even remember them.”

I told them that I was probably going to get in legal trouble but I would send only a few back and keep those they hadn’t seen. After serious consultation, we all agreed this was a good plan. I took a deep breath and continued decorating the house.

In addition to being a mom, I am a behavioral neuroscientist, a professor and a generally serious-minded, reality-based person. So what in the world had I just done? Why did I invent this incredible story in a desperate bid to protect my daughters’ belief in Santa, instead of seizing it as a teachable moment to tell them the truth?

While it may seem that I had abandoned my scientific training, nothing could be further from the truth.

Although children are born with a full set of 86 billion brain cells, or neurons, the connections between these neurons are relatively sparse during these early years. As their brains develop — as more and more micro-thread extensions form between neurons, and neurochemicals zap across the tiny gaps — children slowly learn about the rules of the physical world, and the distinctions between fiction and nonfiction. Eventually, they learn that reindeer can’t fly, that Santa can’t visit every child’s home in one single night and, even if he could make such a trip, there’s no way he could eat all those cookies. Magical beliefs are pruned away as mature neural circuits reflecting real-world contingencies become solidified.

Luckily, however, we don’t completely lose those old ways of thinking, because the brain appears to retain a mechanism for neural time travel. By this, I don’t simply mean that adults have warm memories of having believed in Santa Claus. Pascal Boyer, a professor of memory at Washington University in St. Louis, differentiates between what he refers to as episodic memories — the first time we sat on Santa’s knee or the year a blizzard knocked out the electricity — and mental time travel memories, or M.T.T. These come closer to re-experiencing a remembered event. Professor Boyer describes how neuroimaging evidence indicates that, when certain events are recalled — presumably after being triggered by familiar sights, smells or sounds — emotional brain areas are activated as well as visceral responses. You relive the feelings you experienced in the past. These recollections can be thought of as full body and brain memories.

This can be traumatic, as it is likely to be for people who suffer from post-traumatic stress disorder. Or it can be more mundane. Imagine that someone had a chili dog before riding a roller coaster and then got sick. For years, he may be overcome by nausea whenever he encounters a chili dog — even if he knows perfectly well it was the motion of the ride that made him ill. When the brain considers something to be important, it is difficult to extinguish its responses to conditioned memories. Thankfully, it can happen for happy memories as well.

This notion of mental time travel tells me it was right to try to keep Santa alive for my daughters. For every year I layered another set of Christmas memories into their brains, the easier it would be for them to relive those feelings.

From my own childhood, all those years of reciting “ ’Twas the Night Before Christmas,” smelling fir trees, and going to bed with all the anticipation of a cocaine addict about to get the biggest hit of her life have become a part of my brain’s permanent holiday infrastructure.

(Incidentally, neuroscience confirms another bit of Christmas wisdom: that the anticipation of the holiday can be as exhilarating as receiving the actual gifts. Rodent research suggests that addicted rats experience pleasure, neurologically speaking, when they anticipate receiving cocaine, even if they don’t actually consume it.)

Today, I am so reality-based that my daughters jokingly refer to me as Bones, after Fox’s stoic, almost Aspergerish forensic anthropologist. Even so, because my holiday memories were consolidated at a time when my brain effortlessly conjured up images of flying reindeer, I still feel a bit of that Christmas magic when I encounter holiday sights, smells and sounds. Like Pavlov’s slobbering dogs, my “Christmas spirit” is the result of conditioned responses that have been consolidated in various areas of my brain, and the right sensory cocktail of sights and smells can still give me a holiday high.

So, although I was in mom-mode and not neuroscience-mode when I came up with that cockamamie story about Santa’s bad back, neuroscience research confirms the benefits of trying to assure that my girls have an emotional holiday portal for their future adult brains. I believe this is just as important as their childhood vaccinations — as it is for all children, whether their memories are of Christmas or of other celebrations and traditions. Throughout their adulthood, even when I’m no longer around, the sight of Santa will allow my daughters, once again, to see the world as a child would, if only for a few fleeting moments.

Kelly Lambert is a professor of neuroscience at Randolph-Macon College and the author of “The Lab Rat Chronicles: A Neuroscientist Reveals Life Lessons From the Planet’s Most Successful Mammals.”