引言：古往今来，梦一直是一个令人有无限想象空间的话题。高中时学过《梦留天姥吟留别》，这首诗把梦境的浪漫和诗人的洒脱展现的淋漓尽致，可以说是古人关于梦的一篇绝唱。当然也有苏轼的《江城子》中“千里孤坟，无处话凄凉”的现实中无法释怀的相思与忧伤。近现代，梦成了大家孤心苦诣的研究对象，弗洛伊德以精神分析方面入手，为此撰写了关于梦的基础性论著。现代关于梦为题材的电影也搬上银幕，最令人震撼的当属小李子主演的《盗梦空间》，多年后仍然无法超越的经典。
梦对于我们来说很近，但又很远，所以对于我们来说，既神秘又向往，既常相遇又常相忘。
整理：2023年10月24日于北城家园
Why Do We Forget So Many of Our Dreams?
来源: https://www.scientificamerican.com
If you've ever awoken from a vivid dream only to find that you can't remember the details by the end of breakfast, you're not alone.
如果你曾经从一个生动的梦中醒来，却发现在早餐结束时你不记得细节，你不是一个人。
Dreaming happens mostly (though not always exclusively) during rapid eye movement (REM) sleep. During this sleep stage, brain activity looks similar to that in a waking brain, with some very important differences. Key among them: during REM sleep, the areas of the brain that transfer memories into long-term storage— as well as the long-term storage areas themselves—are relatively deactivated, says Deirdre Barrett, a dream researcher at Harvard Medical School and author of the book The Committee of Sleep (Oneiroi Press, 2001).
做梦主要发生在眼球快速运动睡眠（REM）阶段（尽管不一定完全如此）。 在这一睡眠阶段，大脑活动与清醒时相似，但有一些非常重要的区别。 哈佛大学医学院的梦研究专家、《睡眠委员会》（Oneiroi Press，2001 年）一书的作者迪尔德丽-巴雷特（Deirdre Barrett）说，其中最关键的一点是：在快速眼动睡眠期间，大脑中将记忆转移到长期存储区的区域以及长期存储区本身相对处于非激活状态。
Short-term memory areas are active during REM sleep, but those only hang on to memories for about 30 seconds.
短期记忆区域在快速眼动睡眠期间是活跃的，但这些记忆只能维持大约30秒。
"You have to wake up from REM sleep, generally, to recall a dream," Barrett says. If, instead, you pass into the next stage of sleep without rousing, that dream will never enter long-term memory.
“一般来说，你必须从快速眼动睡眠中醒来，才能回忆起一个梦，”巴雷特说。相反，如果你没有醒来就进入了下一阶段的睡眠，那么这个梦将永远不会进入长期记忆。
REM sleep occurs about every 90 minutes, and it lengthens as the night drags on. The first REM cycle of the night is typically just a few minutes long, but by the end of an eight-hour night of sleep, a person has typically been in the REM stage for a good 20 minutes, Barrett says. That's why the strongest correlation between any life circumstance and your memory of dreams is the number of hours you've slept.
快速眼动睡眠大约每90分钟发生一次，并且随着夜间时间的延长而延长。巴雷特说，晚上的第一个快速眼动周期通常只有几分钟，但在8小时的睡眠结束时，一个人通常会进入快速眼动阶段20分钟。这就是为什么所有的生活环境与你的梦境记忆之间最紧密的关联就是你的睡眠时间。
If you sleep only six hours, you're getting less than half of the dream time of an eight-hour night, she says. Those final hours of sleep are the most important for dreaming. And people tend to remember the last dream of the night— the one just before waking.
她说，如果你只睡6个小时，你的做梦时间还不到8个小时的一半。最后几个小时的睡眠对做梦来说是最重要的。人们往往会记得当晚最后一个梦——醒来前的那个梦。
Other factors also contribute to whether you'll remember your fantastic nighttime adventures, Barrett says. Women tend to remember a few more dreams than men, on average, according to a 2008 meta-analysis of multiple dream studies. Young people remember more dreams than older people, multiple studies have shown. Memory of dreams increases in kids from the age at which they can communicate about those dreams, plateaus from the early teens to the early 20s and then very gradually declines in adults over the rest of their life span, Barrett says.
巴雷特说，其他因素也会影响你是否会记住你奇妙的夜间冒险。根据2008年对多项梦境研究的荟萃分析，平均而言，女性往往比男性记住更多的梦境。多项研究表明，年轻人比老年人能记得更多的梦。巴雷特说，孩子们从可以交流梦境的年龄开始，对梦境的记忆力就会增加，在青少年早期到20岁早期达到平稳期，然后在成年人的余生中逐渐下降。