To explain those outsized brains, evolutionary scientists have pointed to such occurrences as meat eating and, perhaps most determinatively, our early ancestors' need for social interaction.
On the science side, genetics, the brain sciences, evolutionary biology, and paleontology will be seen in a different light.
Trained in philosophy and neuroscience, Taylor seeks to describe and define cruelty, to distinguish between callous brutality and sadism, and ground them in the workings of the human brain and evolutionary theory.
"The real take-home message here is that advanced behaviors, like making sophisticated stone tools, do not necessarily require a large, modern, humanlike brain," says evolutionary anatomist Fred Spoor of University College London.
Considering the extreme plasticity of the fish brain, drawing evolutionary inference from wild-collected material alone can be challenging, and easily misleading.
The great promise of comparative neuroscience is to understand why brains differ by investigating the relations between variations in the organization of different brains, their evolutionary history, and their current ecological niche.
Human brains are evolutionary marvels in that they have kept our species alive for 40,000 years.
Dr. Pepperberg reported the result with appropriate understatement: "That zero was represented in some way by a parrot, with a walnut-sized brain whose ancestral evolutionary history with humans likely dates from the dinosaurs, is striking".
And yet, once you took that daisy, your brain flipped an evolutionary switch.
Karl Popper develops in the book The Self and Its Brain a similar evolutionary argument.
