Last week, the esteemed journal Animal Cognition published a review paper on fish that concludes, "fish perception and cognitive abilities often match or exceed other vertebrates." In fact, says fish scientist Dr. Culum Brown, "fish have a high degree of behavioral plasticity and compare favorably to humans and other terrestrial vertebrates across a range of intelligence tests."
As just a few examples, fish: can "perform multiple complex tasks simultaneously" due to cerebral lateralization, a trait that was until recently thought to be uniquely human; can recall the location of objects using feature cues, a capacity developed by humans at approximately the age of six; "have excellent long-term memories"; "cooperate with one another and show signs of Machiavellian intelligence such as cooperation and reconciliation"; and can use tools, another "in a long list of skills that was supposed to be unique to humans."
Dr. Brown also notes that of course fish feel pain, since "it would be impossible for fish to survive as the cognitively and behaviorally complex animals they are without a capacity to feel pain." In the paper, he points out that pain perception is essential to animal survival and that it has deep evolutionary origins across all vertebrate species.
Farm Sanctuary's Bruce Friedrich caught up with Dr. Brown by email.
BF: How long did you work on this review? How many research studies did you review to come to your conclusions?
CB: I've been working on fish cognition for about 20 years, so a lot of the experiments I refer to are mine or those of close colleagues. I edited a book called Fish Cognition and Behaviour which came out in 2006, and the second edition came out in 2011. So I was already well versed in the literature. To actually sit down and condense this massive body of work into a single paper took about 6 months (most of my sabbatical). And then it took another 6 months going through the review system.
My paper directly refers to about 185 papers, but obviously this is me picking the literature that I particularly like or am very familiar with. I read many hundreds of papers in addition to those that are directly cited. I suggest that most people would not be aware of the huge body of scientific literature in this area.
BF: Do you see this paper primarily as a work of biology, or philosophy, or both, or...?
CB: The vast majority of this paper is biology, pure and simple. The only philosophical part relates to my dealing with the topic of consciousness. But this is no more philosophical than you trying to understand what other people feel. You can never really do that with any certainty. We make a lot of assumptions based on our own experience and project them onto others. Fish are similar enough to humans that we can safely do the same thing for them.
BF: Were there any surprises for you when you set out to write this paper? Did you learn anything about fish cognition or sentience that you hadn't expected?
CB: I don't often worry about consciousness and sentience largely because this really falls into the realm of philosophy. I have a Ph.D. but don't philosophize overly, which is ironic. Few hard core scientists would make the leap across the divide. One only does so with the utmost caution. In this instance, however, I think that the scientific evidence provided a sufficient bulkhead to breach the divide. I think we can be as sure about consciousness in fish as we can in any other animal. Before starting the review, I was reluctant to make the crossing.
BF: What do you wish people knew about fish? If you could change or correct any common belief about fish, what would it be?
CB: The big issue here is that people don't treat fish the same way as they do other animals. It's complicated, but it boils down to the fact that most people just don't understand them and can't relate to them. If you don't have that connection, you are less likely to feel any empathy. To me it's a no-brainer; I instinctively treat animals with the utmost kindness and respect. So I expect people to treat their goldfish in the same manner as they would their pet dog. Fish are similar to humans in so many ways. This is the message we need to get across.
BF: Do you see any change in attitude toward fish? Do you have any hope that there will be a shift in the thinking about them?
CB: My mission in life is to make people think about fish as something other than food. This perception is slowly changing (think Dory from Finding Nemo). It's a big task though. Most folk have no clue about what goes on in their rivers and oceans. Out of site out of mind. That includes the critters that live in them. Hopefully my work with open people's eyes and help them see fish in the same way that I do.
BF: There's a lot of information in your article. If you had to pull out one section to highlight, which one would you select? How would you describe it to a lay person?
CB: I personally work on spatial learning in fishes quite a bit, and I think it is fair to say that fishes' abilities in this area are just as good as any vertebrate, including humans. I can be reasonably certain, though, that the concluding section on pain is going to attract the most attention. I can summarize this in just a few sentences. 1) The physical ability to feel pain in humans is directly derived from a fish-like ancestor. The nerves, etc., are identical. 2) The emotional response to pain is intimately tied in with the physical detection of pain; they are part and parcel of a key survival system. 3) Pain perception and the associated psychological response evolved to protect all animals from harm. 4) Pain perception and the associated psychological responses are a basal form of consciousness. If dogs feel pain, fish feel pain.
BF: People tell me, "well fish get hooked again and again, so they must not feel pain." What do you say to that?
CB: They need to eat. There is too much uncertainty in the world to let a meal go by. Many will strike even when they are completely full. That part is instinct. But you actually have to train hatchery-reared fishes to recognize and attack live prey. Having said that, there is also plenty of evidence that shows that fish can and do develop hook shyness, even after just a single exposure. Sometimes this shyness can last over a year. People will often say to me, "but I keep catching the same fish." Well yeah, if you were starving and someone kept putting a hook in your hamburger (say 1 in every 10 had a hook) what would you do? You keep eating hamburgers because if you don't you starve to death.
BF: How long does it take a fish to suffocate to death?
CB: It depends on the species. If you landed a tuna or mackerel, they'd be dead in 10 minutes. It's not a pretty way to go. The oxygen can still cross the gill membrane while it is wet, but it won't be enough to keep the fish alive. So unlike drowning in humans, where we die in about 4 to 5 minutes because we can't extract any oxygen from water, fish can go on for much longer. It's a prolonged slow death most of the time, which is pretty horrible, when you think about it.
BF: What sorts of practices toward fish do you think should change?
CB: The main thing is to consider fish in the same way you would any other animal. If you like to go out shooting stuff, well that is no different from fishing. I am not opposed to fishing or eating meat. The main thing is that we should kill the animal as swiftly as possible and inflict the minimal amount of stress and pain.
BF: How does your work fit in with Farm Sanctuary's "Someone, Not Something" project?
CB: The Someone Project basically tries to get people to treat animals as they would other people. Each animal is unique, has an identity and a personality. Each is special. The folks who run the project obviously would like to see people stop eating animals, period. I can certainly sympathize with that perspective, but I'm a biologist at the end of the day, and I recognize that humans have always eaten animals. The main thing that we both agree on is that animals should be treated with respect, and we have a duty of care towards them that demands that we reduce pain and suffering wherever possible.
BF: Thank you very much, Prof. Brown, for this paper and for your efforts on behalf of our finned friends.
CB: Thanks for your interest. I'm hoping that this paper can change public perception of fish intelligence. This is my "life goal," I guess you might say. I've always had a huge amount of empathy for all animals, and I just can't understand why people think fish don't also deserve our empathy. I've known this instinctively since I was a little kid, saving fish in the empty pond. Thirty odd years later, and a considerable amount of education, I'm now in a position to prove it.
Dr. Culum Brown is a professor in the Department of Biological Sciences at Macquarie University. He is co-editor of the book Fish Cognition and Behaviour (Wiley Blackwell), editor of the journal Animal Behaviour and assistant editor of The Journal of Fish Biology.