Skip to Content, Navigation, or Footer.
The Tufts Daily
Where you read it first | Saturday, June 15, 2024

Q&A: Diana Reiss decodes the dolphin Rosetta Stone

Studying dolphin communication and behavior with Professor Diana Reiss.


A dolphin jumps above water.

Although dolphins are recognized for their large brains and intricate social structures, the extent of their self-awareness was not widely acknowledged until Diana Reiss, a professor at the cognitive and comparative psychology program of The City University of New York, published her groundbreaking work. As a leading expert in dolphin communication and cognition, Reiss introduced innovative mirror self-recognition tests. By strategically marking dolphins in an area not visible to them, such as above their eyes, Reiss observed their reactions to seeing their reflections and playful investigations of marked body parts. These behaviors were traditionally associated only with humans and great apes, yet Reiss’ groundbreaking work revealed that dolphins also exhibit self-awareness.

As an aspiring marine biologist, I first learned of Reiss’s work at a very early age and have since discovered the depth of her research, like her study of dolphins’s capacity to exchange functional vocalizations with humans. Reiss is the author of “The Dolphin in the Mirror: Exploring Dolphin Minds and Saving Dolphin Lives” and is a dedicated animal welfare activist. I invited Reiss, a scientific researcher whose work has an enduring influence on marine mammal biology and bioacoustics, and as an activist, writer and educator, to speak about her research as part of this series. 

Editor’s note: This interview has been edited for length and clarity.

Amelia Macapia (AM): An important aspect of your research is identifying patterns. Could you explain how patterns function in your research and how you started looking for patterns in dolphin behavior and vocalizations?

Diana Reiss (DR): Often a good way to start is by just observing, not coming in filled up with ideas about what something should look like. Give yourself time to watch dolphins, to listen and to see what patterns emerge. It personalizes the work a great deal.

AM: Are the parallels between human language and dolphin whistle language simply analogous or do they identify something deeper about ourselves and our own primordial history?

DR: Dolphins have a rich repertoire of whistles. They use different whistles depending on the groups they are in and what they are doing. We have some ideas about the kinds of whistles they use, but they seem to vary a great deal in terms of both the parameters, as well as the nature of the contours — how frequency changes over time. There are also a huge number of other types of whistles they use, including pulsed wide-band calls and echolocation. We presume that echolocation has been primarily used for navigation. The animals will send out pulses of sound clicks and then get reflected echoes back that give them orientation. The echoes give them information back about their world, and where others are relative to them. But we don’t know if they get other kinds of information in echoes or if they use them in any kind of communicative way. We have learned from studies in other labs that one animal can actually eavesdrop on the returning echoes and be able to respond and say which item was the target. So they don’t even have to put out the beam to be able to interpret the patterns that they are getting back. This suggests that other dolphins may be able to read the incoming echoes of other animals and get information.

But, I think we are still pretty far away from even understanding the smallest unit that may comprise a whistle and whether or not those whistles may be used in combination with other whistles. If I say “I am going to the store,” I can mix up the different words of that sentence, or make other sentences out of them. Those words are made out of smaller units of sounds called phonemes and morphemes. The duality of patterning makes our language generative, so that we can take a small number of elements and combine them and recombine them over and over again to make an infinite number of sentences that are meaningful. The question is whether something like that exists for dolphins.

AM: How do you immerse yourself in the sensory or cognitive or emotional worlds of the animals you’re studying as opposed to just analyzing them?

DR: When we start working with different animal species, we try to stay objective and unattached as much as we can. We name all of our animals with numbers and letters. But we start noticing that there are differences in personalities in our scientific studies. To say “personality” is fairly new in science. It’s very hard to be completely detached when you’re working with charismatic animals and you’re interacting with them. It’s a normal reaction to have relationships with others, including other animals. In science, we have an “it-ification” problem — the very language we use when we talk about animals can affect how we perceive them ourselves as scientists, but also how others perceive them in terms of emotion. There were so many times when I would refer to dolphins as “he” or “she” in papers that I would submit for publication, and the editors would come back and cross it out and put “it” instead. And I said no, I want to call it a “he” or “she” or by their name. Different dolphins show different types of behavior; maybe one will tend to observe the other more, another will be more reserved. But that is what makes it so interesting. These are not machines any more than we are.

AM: An important key to understanding dolphin communication was what you once called “the dolphin Rosetta Stone.” What was your experiment with the dolphin Rosetta Stone? What most surprised you about the findings of this experiment?

DR: I was interested in the cognitive and communicative data people were getting by teaching vocalizations to chimps and African gray parrots. Virtually all of these studies have shown us that other species can learn to use artificial codes in referential ways. The question is: Do they use grammar? And how do they organize it?

In all of these studies, one of the key findings is that the animals have to work in a social context with communication. With dolphins, when you put them in a rigid situation where they are just interacting with a machine, it does not look anything like communication. On the other hand, if you are directly interacting with the animals, you are opening the possibility for all sorts of inadvertent cuing, like the Clever Hans phenomenon. I wanted to create a test of their communication and social learning that preserves sociality but also prevents cuing, so we created a keyboard. The keyboard gave the dolphins choice and control over the contingencies of the system, which we could use to passively record and identify patterns that might be referential in nature.

With the Rosetta Stone underwater keyboard, there were nine simple keys that would change their position from minute to minute based on a pseudo-randomized schedule. If the dolphin hits a key, they hear a computer-generated whistle, and they get a corresponding object or an activity — for instance, a ball. What we saw looks very much like what we see with young children; the dolphins learned by association between the keys, sounds and objects. Dolphins quickly began to press the symbols for items they preferred. They began imitating the sounds from the keyboard, first hitting a key, hearing the computer-synthesized whistle and then emulating it. But they also began using these whistles in ways that looked like they were being associated with the object. For instance, they started coming up to the keyboard, whistling the sound for “ball” and pushing the “ball” key — that is called productive use. We knew that they had associated those sound signals with the visual forms. But then we would find them creating “facsimiles” of the sounds when they were approaching or playing with objects, and we started seeing evidence that they could combine the sounds for “ball” and “ring” into one compound continuous whistle. That was maybe because they were producing that sound when they were playing with the balls and rings together, that they were putting signals together or that they made up a word for combined activity. So with these contingencies that they could explore on the keyboard, we saw what their interests were.

AM: One of the key features of language is following an order. There is a great scene in your book where the dolphin you are studying, Circe, puts you in a “timeout.” In the book, you describe how you would toss fish to Circe, and if she swam away, you gave her a “timeout,” where you would stand with your back to her. One day, you accidentally gave her a fish with its fins intact, and she spit it out and swam to the other end of the pool, remaining in a vertical position with her back to you for several minutes. She was putting you in a timeout. How did that happen, and what was that moment like for you?

DR: I was in my Ph.D. program, and this was my first real experiment. When that first happened, I was amazed, because I wondered if she could honestly be understanding that this was a correction mechanism. Does she understand why I use it? It’s hard to publish anything based on just an anecdote, so I decided to turn that into an experiment. So I purposely gave her some uncut tail sections, and each time she would put me in a timeout. That was one of the most interesting findings from that study because instead of looking at discrimination, I was looking at whether they could learn associations between things and how that matched preferences. But the fact that she turned the behavior back on me made me think: These are really magnificent minds and we have to think of creative ways to understand them.

AM: What is it like to write about animals as if they are characters in a book? How do you navigate the balance between maintaining scientific accuracy and avoiding anthropomorphism, while also conveying empathy, care and compassion towards the animals you are writing about?

DR: Humans diverged from cetaceans [dolphins, whales and porpoises] over 95 million years ago, but there are still these remarkable patterns that connect us. For example, when we give dolphins mirrors, they behave the same as humans. First, the dolphins act like they’re looking at conspecifics [members of the same species]. Then, they shift to contingency testing where you see these unusual repetitive behaviors in front of a mirror, and the dolphin realizes there’s a match to what they are doing, which is not what they would normally see in a conspecific across from them. This seems to be where they recognize themselves. And then they go on to the third stage, which is self-directed behavior, using the mirrors as a tool to examine themselves. The dolphins seem to be interested in looking at parts of their body they can’t see without a mirror. They like to examine the insides of their mouths or their eyes, or come up close. They do certain behaviors that would be analogous to a dance in front of a mirror, spinning or twirling; it’s playful behavior. They’re watching themselves do things they can’t see. And it’s not behavior they do towards conspecifics, so this is another pattern that emerges.

AM: If we are going to survive this new epoch characterized by mass extinctions and sweeping changes to ecological systems, how should our relationships with animals begin to develop?

DR: There’s a real relationship between knowledge, empathy and respect. It’s my hope that with increased knowledge, there will be increased empathy and respect, and we will become more concerned about their habitats because their habitats are our habitats. I think it’s our responsibility as scientists to find effective ways to share our science and engage the public because that can change policies.