Many people are fully convinced that animals such as dogs, cats and other mammals are conscious, but what about all the others? What about, birds, fish, octopuses and even crabs and insects? If a dog is conscious, what about the fleas living in the dog’s fur? Are they as conscious as the dog, or conscious but less so? And what does being conscious actually mean? Can we measure it? What sort of evidence can we look for to help us decide which animals might not just behave ‘as if’ they were conscious but actually feel pain, pleasure and suffering as we do? 

This book is about how we might go about finding answers to these questions. Unlike many other books on the subject, it does not try to convince you that particular animals are or are not conscious or even of the virtues of a particular theory of consciousness. Rather, it’s aim is to look at the evidence that different people have put forward to claim that animals are conscious and to see how convincing it is. It is intended as a guidebook to the many different claims that have been made about which animals are conscious. My hope is that everyone – whatever their views on animals and how conscious they are  – will find something of interest, something to make them think, something to help them answer the question ‘Who is conscious?’

Along the way, we look at many different sorts of evidence. The behaviour of animals themselves is a good starting point but has the problem that while we can observe what animals are doing, we can’t ask them what, if anything, they are feeling. Here research on human consciousness has the advantage. We can  ask people what they are consciously experiencing at the same time as using brain scanning techniques to tell us what their brains are doing. The success of studies on human consciousness have, in turn, inspired new studies on animals. If there are some problems that humans can only solve when they are consciously aware of what they are doing and animals can also do these same tasks, does this show that the animals, too must be conscious?

 We look at whether this is true or not. A looming problem is that most, if not all of the criteria that have so far been suggested for consciousness in animals can be met, or will plausibly soon be met, by machines. Computer can integrate information, self-monitor, handle motivational trade-offs and do many other things often held to be the ‘signatures’ of consciousness. Awareness of what computers can do provides a sanity check on over-hasty conclusions about animal consciousness.

The book concludes with some guiding rules for how to think clearly about animal consciousness.