来源：《新科学家》
原文刊登日期：2021年7月7日
Given that there is a variety of conscious experience across the animal kingdom, it is natural to ask when and how consciousness first emerged. Can we thank a single common ancestor? Or did it evolve independently in different lines?
考虑到在整个动物王国有各种各样的意识体验，问意识何时以及如何首次出现是很自然的。人和各种动物的意识能力来自共同的祖先吗？或者它是在不同的线路上独立进化的?
Andreas Nieder at the University of Tübingen favours the latter explanation. He recently conducted an ingenious experiment to discover the brain processing underpinning visual consciousness in crows. The birds were trained to respond to different coloured squares. Neurons in a region called the pallial endbrain lit up whenever the crows reported seeing the squares, but not when they failed to spot them, suggesting that this area is essential for their conscious visual perception. In humans and primates, a different part of the brain, the prefrontal cortex, performs the same job. For this reason, Nieder thinks that consciousness probably emerged separately on multiple occasions, in much the same way that wings appeared separately in insects, birds and bats.
Tübingen大学的安德烈亚斯·尼德赞同后一种解释。他最近进行了一项巧妙的实验，以发现支撑乌鸦视觉意识的大脑处理过程。经过训练，这些乌鸦对不同颜色的方块有反应。当乌鸦报告看到正方形时，大脑皮层末端的神经元就会被点亮，但当它们没有发现正方形时就不会被点亮，这表明这个区域对它们有意识的视觉感知至关重要。在人类和灵长类中，大脑的另一部分——前额叶皮层——执行着同样的工作。出于这个原因，尼德认为意识可能在多个场合分别出现，就像翅膀在昆虫、鸟类和蝙蝠中分别出现一样。
Eva Jablonka at Tel Aviv University and Simona Ginsburg at the Open University of Israel take a different view. In their book The Evolution of the Sensitive Soul, they argue that birds, mammals and other vertebrates inherited consciousness from a common ancestor. Their argument hinges on a type of thinking known as unlimited associative learning, which involves learning about novel stimuli and linking them together. It also entails forming chains of such links so that the same stimulus can be interpreted in different ways depending on the context.
特拉维夫大学的伊娃·雅布隆卡和以色列开放大学的西蒙娜·金斯伯格持不同看法。在他们的《敏感灵魂的进化》一书中，他们认为鸟类、哺乳动物和其他脊椎动物从一个共同的祖先那里继承了意识。他们的论点基于一种被称为“无限联想学习”的思维方式，即学习新的刺激，并将它们联系在一起。它还需要形成这样的链接链，以使相同的刺激可以根据环境以不同的方式解释。
Importantly, these associations can be updated: something that triggered danger may come to be a sign of reward if circumstances have changed. Jablonka and Ginsburg believe that this kind of complex learning is impossible without consciousness to direct attention, evaluate different cues in the environment and integrate experiences over time. So, what can it tell us about the origins of consciousness?
重要的是，这些关联可以更新：如果环境发生变化，触发危险的东西可能成为奖励的信号。Jablonka和Ginsburg认为，如果没有意识来引导注意力，评估环境中的不同线索，并随着时间的推移整合经验，这种复杂的学习是不可能的。那么，关于意识的起源，它能告诉我们什么呢？
Unlimited associative learning has been documented in many diverse species. “Even little fish are able to do this,” says Jablonka. That leads her and Ginsburg to propose that consciousness must have emerged in early vertebrates around 530 million years ago.
无限联想学习在许多不同的物种中都有文献证明。“即使是小鱼也能做到这一点，”雅布隆卡说。这使得她和金斯伯格提出，意识一定是在5.3亿年前的早期脊椎动物中出现的。
They suspect certain groups of invertebrates, including arthropods like honeybees and spiders, can also think in this way. If so, their earliest ancestors evolved consciousness independently of vertebrates, around 500 million years ago. The shell-less cephalopods are relative latecomers to the table. Consciousness in octopuses, cuttlefish and squid originated around 300 million years ago. “I think it is one of the most promising approaches we have at the moment for how to study the evolution of consciousness,” says Jonathan Birch at the London School of Economics.
他们怀疑某些无脊椎动物，包括节肢动物，如蜜蜂和蜘蛛，也会以这种方式思考。如果是这样的话，它们最早的祖先大约在5亿年前独立于脊椎动物进化出了意识。无壳头足类动物相对来说是进化时间表上的后来者。章鱼、墨鱼和乌贼的意识起源于大约3亿年前。伦敦政治经济学院的乔纳森•伯奇表示：“我认为，这是目前研究意识进化最有希望的方法之一。”