I really enjoyed reading this book and would recommend it to anyone looking to learn about the current state of our scientific understanding of animal cognition.

A lot of this book was imploring readers, as the leaders in the field have been working to implore scientists in all related fields, to approach the analysis of animal intelligence through understanding of that animal's unique perspective and experience (i.e., it's unwelt). This means that the proper way to approach the intelligence of a bat, for example, is to consider what it is like for a bat to be a bat, not to anthropomorphize what a human would experience if they were a bat. Put another way, the world does not exist in a way just to be perceived by human senses, but it's for all perceptions and all animals have uniquely evolved to experience this world in different ways.

One thing that surprised me was how recently it was for ethology, or the science of animal behavior, to become a legitimized science-- not until the first half of the 20th century. Before that, the study of animals was much colder and narrower, where behaviorists perceived everything animals did as a learning mechanism in response to simple rewards and never considering that animals had their own desires or intentions. A huge breakthrough that took even longer to take hold in the scientific world was the idea of studying animals in their natural environments, as opposed to under the stress of a man-made experiment setup, would give better insights into these animals' minds. A war had to go down between the various fields (ethology, behaviorism, comparative psychology) before the spoils of the ethologists could be realized-- another really interesting case study in how different scientific fields can come together to be stronger once people stop feeling compelled to blindly follow their 'home' science view. One of the victories of the ethologists, like Frans de Waal, was the stressing of the importance of methodology being tight. Experiments need to be tailored to the species (when testing the intelligence of chimps and children, is it really fair to compare the results when the child was tested while sitting in the lap of a parent while being instructed by a member of his or her own species and being congratulated and egged on the whole time and the chimp was isolated in an unfamiliar sterile room given much fewer instructions and encouragement?) and also address unanticipated external factors (e.g., mice who performed more poorly in intelligence tests when the scent of a male human was present or capuchins testing poorly when tested by one jittery student compared to another calm student).

Some interesting tidbits I picked up and stuck with me include:
- The study of animal culture, outside of instincts, shows how much animals want to conform and will do as they see, just like humans. One breakthrough example of this was the spreading of washing sweet potatoes before eating in certain macaque tribes.
- If you've ever gotten sick after eating a specific type of food, and then the thought of that food forever made you queasy-- there's a name for that, the Garcia Effect! And it seems you don't have to be a hyper-intelligent human for that to take hold, because Garcia found the same tendency in mice-- even years after the ill effects.
- The Wallace Problem surrounds the idea that scientists have long been compelled to keep humans separated from animals by means of science, as a means to validate our feelings of superiority and special place in the universe as the 'most intelligent' species. The deciding factor on what counts as cognition/consciousness and therefore makes humans special has a long history of being a constantly moving goal post. Frans de Waal argues that this adherence to the preconceived conclusion of human superiority, what he deems neocreationism, still looms large in academic circles that are eager to "keep the human mind out of the clutches of biology."
- Pachyderms might be the next frontier on animal cognition, but they are too big to be confined to a university or laboratory setting. That's what's led to the current state of the field where it's focused on the small brain perspective on cognition.
- It's important to get away from the idea of hyper-uniqueness among humans. Animals have their own cultures, they cooperate, they plan and remember, they recognize social hierarchy and play politics within it, they recognize the perspective of others and the ability of others to recognize their own cognition, and more.
- Just because an animals sense seems alien to us, it doesn't mean it should be cognitively dismissed. One study showed how elephants can tell the tribes of humans it encounters apart based on their language and/or accents alone.
- There has even been signs of advance cognition in invertebrates-- specifically octopus cognition. Octopi can be closed into a jar and use their tentacles to twist the lid and get out, and the current understanding of their nervous system places independent neuron centers throughout the different tentacles that can all operate independently and interact with each other, rather than having a central repository of neural activity. The idea that some invertebrates (cuttlefish, too) might not be purely instinct driven machines is pretty world changing.

One of the last ideas that de Waal left with us was that he welcomed people critiquing his studies and theories, noting that "So long as progress is our shared goal, this is how science ought to work." I can only hope in all manners of science, people embrace his umwelt!