"It might not have had anything to do with my choice of wine," I said. 

"No," Zima agreed. "And the AM certainly wouldn't attach any significance to that one happy combination of circumstances. A single deviation wouldn't affect its predictive model to any significant degree. It would still say 'red wine' the next time you asked."

I felt an uncomfortable tingle of understanding. "But human memory wouldn't work that way." 

"No. It would latch onto that one exception and attach undue significance to it. It would amplify the attractive parts of the memory of that afternoon and suppress the less pleasant parts: the fly that kept buzzing in your face, your anxiety about catching the boat home, and the birthday present you knew you had to buy in the morning. All you'd remember was that golden glow of well-being. The next time, you might well choose white, and the time after. An entire pattern of behaviour would have been altered by one instance of deviation. The AM would never tolerate that. You'd have to go against its advice many, many times before it grudgingly updated its model and started suggesting white rather than red." 

"All right," I said, still wishing we could talk about Zima rather than me. "But what practical difference does it make whether the artificial memory is inside my head or outside?" 

"All the difference in the world," Zima said. "The memories stored in the AM are fixed for eternity. You can query it as often as you like, but it will never enhance or omit a single detail. But the implants work differently. They're designed to integrate seamlessly with biological memory, to the point where the recipient can't tell the difference. For that very reason they're necessarily plastic, malleable, subject to error and distortion." 

“这跟我选择什么酒没什么关系吧。”我说。  

“确实没有，”齐玛赞同道。“备忘录助手肯定不会把这样一个令人开心的阴差阳错当成是一种特例，应该把这个特例单独记录下来，供下次参考。这样一个小小的偏差并不会对它的预测模型产生任何重要的影响。下次，它还是会让你选择红酒。”  

我感觉内心突然一阵刺痛，非常不舒服。“但是人类的记忆并不是那样工作的。”  “没错，人类的记忆会牢记这个例外，并且标记上重要意义。它会放大今天下午记忆中吸引人的部分，抑制住不开心的部分：苍蝇一直在你脸周围嗡嗡叫、你在搭船回家时的焦虑心情、以及你知道今天早上不得不去买生日礼物。你所记住的是金色的光辉照耀下的安宁。下一次，你可以随便选择白葡萄酒还是红葡萄酒。以后都随你选。整个行为模式都会因为这个细小的偏差而改变。备忘录助手绝不会容忍那样的事发生。你只有违背它的建议很多次，它才会非常吝啬地更新它的数据模型，然后它才会开始建议你选择白葡萄。”  

“没错。”我说，但我还是希望齐玛能多谈谈他自己，而不是我。“但是移植的人工记忆与外部的人工记忆究竟有多少实际的区别？”  

“简直是天渊之别。”齐玛说，“存储在备忘录助手里的记忆会被永久地记住。不管你询问它多少次，它都不会强化或者忽略每一个细节。但是移植的人工记忆不一样。他们被无缝地整合进生物记忆，移植了人工记忆的人根本区分不了哪些是人工记忆、哪些是生物记忆。正是因为这个原因，移植的人工记忆具备必要的可塑性、易变性，并且会产生错误和失真。”