If a potential mate has managed to pass all these tests, there's still one more: the infamous first kiss,
即便一个潜在的伴侣已经成功通过以上所有的测试，这里还有最后一关：初吻，
a rich and complex exchange of tactile and chemical cues, such as the smell of one's breath, and the taste of their mouth.
初吻是一次内涵丰富而寓意复杂的触觉和化学信息的交换，比如口气和嘴唇的触感。
This magical moment is so critical
这个神奇的时刻如此关键，
that a majority of men and women have reported losing their attraction to someone after a bad first kiss.
以至于大部分的男性和女性均表示曾因为一个糟糕的初吻而丧失了对对方的吸引力。
Once attraction is confirmed, your bloodstream is flooded with norepinephrine, activating your fight or flight system.
一旦吸引力被确认，你的血液和肾上腺素一起沸腾，激发你的“战斗或逃跑”系统。
Your heart beats faster, your pupils dilate, and your body releases glucose for additional energy,
你的心跳加速，你的瞳孔扩大，你的身体也释放出葡萄糖来提供更多的能量，
not because you're in danger but because your body is telling you that something important is happening.
这不是因为你面临着危险，而是你的身体在告诉你这件事十分重要。
To help you focus, norepinephrine creates a sort of tunnel vision, blocking out surrounding distractions,
为了帮助你专心肾上腺素，创造出一种管状视力防止注意力涣散，
possibly even warping your sense of time, and enhancing your memory.
甚至有可能弯曲你的时间观念并提升记忆力。
This might explain why people never forget their first kiss.
这也许能够解释为什么人们对初吻念念不忘。
The idea of so much of our attraction being influenced by chemicals and evolutionary biology may seem cold and scientific rather than romantic,
我们的大部分吸引力被化学和进化生物学深深影响这个观点也许看上去冷酷又理性，一点也不浪漫
but the next time you see someone you like,
但是下次你见到一个喜欢的人的时候
try to appreciate how your entire body is playing matchmaker to decide if that beautiful stranger is right for you.
试试让你的整个身体都参与配对过程来决定这个美丽的陌生人是否是那个对的人。
