Every time scientists have tried to come up with a set of defining characteristics of what it means to be human, subsequent observation has revealed that there are other species who share those features previously thought to be unique to us...
We are faced with a puzzle: on the one hand, given our shared evolutionary history, we should expect to be quite similar to our evolutionary cousins; on the other hand, given our close genetic relatedness to chimps and bonobos, we should be more similar to them than we actually are. So what gives?
In the following absolutely fascinating presentation, Robert Sapolsky deploys a brief intro into many now classic scientific experiments. Armed with this evidence, he organizes the ways in which we are similar to other species, and how sometimes we take those similarities to hitherto unknown extremes. In the end, he posits his thoughts about some abilities and quirks that may not have any counterpart in the animal kingdom. Agree or disagree, this talk is certainly worth watching.
If you can't get enough Sapolsky, watch him talk about the weird world of toxoplasmosis, or listen to him explain how hormones can affect our minds.
And if you're outside the US and can't watch Hulu, you can also find the talk in the FORA.tv site.