I'm sure De Waal addresses this in more detail in his book, but the omission is perhaps less glaring and capable of destroying the entire argument as you present it to be.
Although it is clear that human language is unique and appears much more developed than any animal communication system observed in nature, no one knows what exactly property of language makes it unique. Indeed, infinite use of finite means, or syntactic structure are often put forward as candidates but syntax and generativity have also been observed in bird song. We simply don't know what the defining feature is that sets language apart from animal communication systems.
Similarly, we can't identify the unique cognitive ability that differentiates us from other animals. Since, as De Waal points out, humans are genetically speaking very close to our nearest sibling species, and we simply don't understand what precisely makes us cognitively different from, say Bonobos, the standard assumption should not be that we're somehow gifted with very special cognitive abilities, but that animal cognition is much more similar to our own cognition than is often assumed. Rather than studying where animal cognition, especially in genetically related species, resembles human cognition, we should be studying where it differs from human cognition.
Keep in mind that anatomically modern humans have only been around for two hundred thousand years, and the explosion of human culture only happened around ten thousand years ago. Not a lot of time for massive evolutionary changes.
My original comment was not just about communication, so I'm not sure what bird calls have to do with any of this. Even so, it is unclear if birds actually have infinite use of finite means in the expressively meaningful way humans do. Regardless, language's communicative ability is only one part of the uniqueness of human capabilities - birds clearly do not have the thought/reasoning capabilities (to which language is tightly entwined) that we do.
We can point to behaviors that are unique to us. Since these behaviors must have some cognitive basis, they can serve to tell us how different we are. There is clearly a reason that no other animals understand abstract math or build rockets that fly into space. We simply haven't seen any evidence of other animals creating new knowledge and explanations using internal, rational thought in the way that humans do.
The original point of my post was simply to suggest that there is, in fact, a "psychological secret sauce" that makes humans different from other animals. We don't yet understand the nature of this secret sauce, but this should not preclude us from doing the things that De Waal wants to do: to understand animals on their own terms and avoid treating them like "defective adult humans" simply because their brains are different.
> Rather than studying where animal cognition, especially in genetically related species, resembles human cognition, we should be studying where it differs from human cognition.
I am unaware of any scientists that think we shouldn't study where animal cognition differs from human cognition. There is no reason to favor differences over similarities, they can both give insights.
> no one knows what exactly property of language makes it unique.
The book Adam's Tongue delves into this. The author distinguishes "Animal Communication Systems" from languages by their linguistics. There are several things that you can isolate in human languages that you never see in animals, though some animals, like bees, come close.
Finally, he presents a hypothesis of how language might have evolved in humans in the context of savannah scavenging. The thinking goes that scavenging an elephant after it dies requires extremely rapid cooperation, because the window of opportunity is a few days at most.
My feeling is that you're never going to be able to find one thing that separates us from animals, that looking for that one thing is bound to fail.
Although it is clear that human language is unique and appears much more developed than any animal communication system observed in nature, no one knows what exactly property of language makes it unique. Indeed, infinite use of finite means, or syntactic structure are often put forward as candidates but syntax and generativity have also been observed in bird song. We simply don't know what the defining feature is that sets language apart from animal communication systems.
Similarly, we can't identify the unique cognitive ability that differentiates us from other animals. Since, as De Waal points out, humans are genetically speaking very close to our nearest sibling species, and we simply don't understand what precisely makes us cognitively different from, say Bonobos, the standard assumption should not be that we're somehow gifted with very special cognitive abilities, but that animal cognition is much more similar to our own cognition than is often assumed. Rather than studying where animal cognition, especially in genetically related species, resembles human cognition, we should be studying where it differs from human cognition.
Keep in mind that anatomically modern humans have only been around for two hundred thousand years, and the explosion of human culture only happened around ten thousand years ago. Not a lot of time for massive evolutionary changes.
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