Dolphin psychology

• TYPE OF PSYCHOLOGY: Comparative; Cognitive; Developmental; Experimental; Social psychology

Like many mammals, when given certain conditioned stimuli, dolphins can be trained to perform a behavior. But how much deeper do their intellectual abilities extend, and under what conditions do they apply? Observations and experiments are unlocking the cognitive abilities of the cetacean mind. Tests of self-awareness, comprehension of complex sentences, and inferential reasoning provide insights into the psychology of the dolphin brain. By studying these complex processes, scientists better understand the mental processes of nonhuman intelligent species.

Introduction

Animal cognition researchers utilize the encephalization quotient (EQ), a ratio of brain to body size, to estimate relative cognitive potential across species. Because brain size generally scales with body size, EQ helps identify animals whose brains are disproportionately large for their size. A high EQ is often associated with advanced cognitive capabilities, though it is not a direct measure of intelligence. Humans have the highest known EQ at approximately 7.4–7.8, but many cetaceans—including dolphins, porpoises, and whales—also exhibit notably high EQs. Among them, the common or Atlantic bottlenose dolphin (Tursiops truncatus) stands out, with an EQ between 4.1 and 5.0, comparable to that of anthropoid apes. The dolphin’s cerebral cortex—the region responsible for higher-order thought processes—is highly convoluted compared to many other species. This region is highly vascularized and oxygen-dependent, indicating significant metabolic investment in cognitive function. Studies of cetacean brains have also identified specialized neurons called Von Economo neurons, which are associated with social awareness and decision-making. Some research suggests that certain aspects of their mental processing—such as perceptual integration or environmental awareness—may, in specific contexts, match or differ from human capabilities.

Dolphin Communication

Dolphins are known for their remarkable social adaptations. They make many associations with each other throughout their lifetime in social groups, called pods. Dolphins display what researchers call a fission-fusion society, meaning that dolphins leave social groups and temporarily join others. This creates the need to communicate with potentially new pods or reunite with previous ones. To make these connections and address one another, dolphins developed ways of identifying themselves and others. This labeling is what scientists have termed signature whistles. Signature whistles are individual-specific calls emitted during separation as well as introduction to individuals. This adaptation to form connections and social bonds has helped dolphins thrive throughout their evolutionary history.

By one year old, calves have developed signature whistles that will remain generally stable throughout their lives. To develop signature whistles, calves use vocal learning, sometimes copying elements from others. One study on six calves in Sarasota Bay showed evidence that calves may learn to modify signature whistles of dolphins they seldom associate with in their communities rather than dolphins with whom they have strong associations. Thus, calves display the ability of vocal learning. This ability suggests that dolphins form a mental representation linked to a given whistle.

The ability to identify other individuals by signature whistles is a novel adaptation, and studying pods over time can show their ability for long-term social recognition. A study by Jason Bruck suggested that dolphins can hold mental representations of signature whistles of other dolphins for up to fifteen and, in some cases, twenty years, despite the amount of time they were associated. The ability for long-term recognition could potentially help dolphins recognize other individuals and help integrate members into groups within their fission-fusion society.

Research at Florida's Dolphin Research Center in the early 2020s further demonstrated dolphins’ ability to imitate behaviors using passive and active acoustic cues. When a dolphin recognizes a behavior by its characteristic sound, it replicates it accurately. With unfamiliar sounds, the dolphin employed echolocation to discern and imitate the action. This flexibility in problem-solving showcases impressive cognitive adaptability.

Comprehension, Reasoning, and Manipulation

The foundational understanding of dolphin comprehension stems from the pioneering research of Louis Herman, who conducted a series of influential studies to examine dolphins’ capacity for inferential reasoning. Dolphins can learn certain signals for different objects and can even learn inverse sentence structures for as many as five items. When given the signaled instructions such as left, basket, right, ball, in, Herman demonstrated that dolphins can understand how to put the ball on their right into the basket on the left. If the instructions ask to do things that are not possible, for example, if an object is not present or if the syntactic structure is not comprehensible, dolphins will reject the request and continue to wait for a meaningful request. This shows the dolphins' ability for rational reasoning and responding.

Herman also showed that dolphins can manipulate their environments to create the ability to respond to requests. For example, one dolphin named Akeakamai was given the instruction to swim through the hoop, but it was located at the bottom of her pool. So, she spontaneously manipulated the hoop by bringing it upright and swimming through it. Akeakamai also spontaneously manipulated her environment when she was told to fetch multiple items. Instead of bringing them back one at a time, she balanced the items with different parts of her body to bring a group of them back at once. This spontaneous manipulation provided evidence that dolphins can think outside given instructions and effectively and efficiently respond.

Dolphins can also understand the ability to create things. Elele, another dolphin Herman studied, understood the concept of creating and, when given the signal, came up with seventy-two spontaneous behaviors over her 144 trials. Thirty-eight of those behaviors were never seen or exhibited before and thus independent of the possibilities of mimicking another dolphin's behaviors or being taught. Elele made them up, illustrating that dolphins can invent things in their own mind and display their ideas.

A 2024 study by King et al. built on the foundational research of Herman, extending his findings with a larger sample size of twelve dolphins in three facilities. The researchers set out to explore the ability of bottlenose dolphins to engage in innovative behavior in response to a trainer's hand gesture command "create," meaning they must perform a new behavior. Trainers withheld reinforcement for repeated actions to encourage originality in each trial.

Like Herman’s Elele, each of the dolphins exhibited creative body movements, vocalizations, or previously learned behaviors displayed with modifications or in unique combinations. However, some dolphins presented with higher levels of creativity than others. As the study progressed, many dolphins expanded their behavioral repertoires, demonstrating adaptive learning and a willingness to experiment.

The findings support Herman’s hypothesis that dolphins are active problem-solvers who can flexibly manipulate learned elements in innovative ways. By expanding the scope of inquiry beyond a single subject and controlling for reinforcement history, the 2024 research strengthens the argument that innovation in dolphins is intentional, repeatable, and rooted in complex cognitive processing.

Joint attention

Due to the dolphin's social nature, researchers wondered if they could understand some of the fundamental skills of human social cognition. Following a gaze is a skill infants can learn by fifteen months old, foreshadowing the comprehension of joint attention. Put simply, it is following the direction someone is looking. It is then followed by understanding and adopting the point for the purpose of directing the receiver's attention to something one desires or pointing as a means to simply share something one found of interest.

Although dolphins cannot point in the human sense, experiments have found that they can understand the point and gaze without previous exposure. One experiment by marine researcher Alain Tschudin tested six dolphins who had never been exposed to pointing. A red bucket and a white container lid were placed to the left and right of each dolphin, and then each was given a hand signal to fetch it. The informant only used right-hand signals to point to the right and cross-body signals to point to objects on the left. The goal was to determine if they could comprehend what object the informant was directing them toward. Over the first twelve test trials, three dolphins performed above chance on pointing; with additional trials, four dolphins performed above chance on pointing. Thus, evidence suggests that dolphins can readily understand a dynamic pointing gesture.

Tschudin used the same setup to test head gazing cues and, instead of pointing, used his head to show the dolphins where the object was. In the first twelve trials, two of the dolphins performed above chance, and with continued trials, two more were above chance. However, the point and head gaze were both dynamic signals, meaning that the movement of the arm or head could have potentially been interpreted by the dolphin as a direction on where to go and not the point or gaze itself. Pack and Herman wanted to test if dolphins could understand the static point, so they conducted an experiment in which objects were placed around the dolphin, and a first informant gave a signal for an action with no destination object. Then, a screen was raised, and the informant maintained a stationary point. Both dolphins tested were virtually errorless in interpreting the signals, supporting the belief that dolphins can understand dynamic and static cues.

Another marine mammal researcher, Mark Xitco, wanted to see if dolphins could create their own cues to make a referential indication toward an object. For six months, dolphins Toby and Bob were exposed to scuba divers who had an underwater keyboard to communicate certain goal objects or areas in which these objects were. Things like toys or food were placed in clear containers, which the dolphin would need the assistance of a tool or a human to open. Spontaneously, the dolphins fixed themselves in front of containers and, using their rostrums or mouth area, began signaling toward the object. This behavior only occurred if divers were present, which can be interpreted as the dolphins' version of pointing. Not only did they spontaneously adopt this referencing of objects, but simultaneously, the dolphins were observed to monitor the diver's attentional condition. Monitoring was defined as Toby and Bob following the divers with their heads while keeping their bodies positioned toward the goal object. It occurred when the divers were far from the dolphin or the object, not when the dolphin and diver were close. Monitoring shows that the dolphin is waiting for the diver's attention and may track the diver’s attention.

This possible early form of understanding others’ attention was explored in a follow-up study by Xitco et al. Dolphins were notably able to employ monitoring and pointing behaviors when the diver was facing forward. Dolphins may use body position and the direction someone is looking to infer where their attention is focused. Not only can dolphins understand human points, but they also instinctively devise their own mechanisms for drawing attention to desired items. Strong evidence suggests that this pointing is referential because it is much more likely to occur in the presence of a diver facing the dolphin, thereby inferring where the diver's attention is according to body positioning. This ability to think outside oneself and attribute mental states to others is evidence of a dolphin's consciousness. Awareness of one's own existence was once thought of as a strictly human trait that separated us from all other animals. This level of consciousness suggested some physical understanding that one is the author of one's body and actions are under one's own control. To demonstrate that dolphins have a sense of body awareness, Herman conducted an experiment in which one dolphin, Elele, had to use nine different parts of her body to carry out different directions given. She succeeded 90 percent of the time in showing different body parts and 68 percent of the time in using different body parts to complete tasks never presented to her before. Furthermore, there was evidence that she recognized some ownership and agency over her body and how it moved, and had a sense of her own body image. She had not previously been exposed to having labels for each body part. Through her ability to incorporate and move her body in different ways to complete tasks, she exhibited an awareness of her own body parts and perhaps a conscious perception that she had control of them.

Diana Reiss and Lori Marino also explored dolphin consciousness in the ability to recognize their mirror images as themselves. During training sessions, two dolphins at the New York Aquarium were under three conditions: marked, sham-marked (touched but no mark left behind), or not handled during training sessions. After each training session, the amount of time for release and investigation of their body in a mirror was significantly greater when they had felt the mark, or sham mark, than when not being handled at all. They did not display any social behaviors toward the mirror, as some animals do when they treat the reflection as another animal. But instead of a significant number of the trials, their first action was a self-directed behavior to view the marking. When the mirror was present and uncovered, dolphins spent more time than in any other condition in the experiment. Thus, during a sham-mark trial, when the dolphin realized it was not marked, it would be more likely to stop its self-directed behaviors. Although dolphin self-awareness requires deeper investigation, there is evidence that they can recognize themselves in mirrors and can align their bodies as a means to investigate certain areas. These findings have also raised questions about dolphin welfare, particularly regarding how their cognitive abilities are affected by captivity compared to natural environments.

Bibliography

Bates, Mary. “The Purpose of Play for Young Male Dolphins.” Psychology Today, 10 June 2024, www.psychologytoday.com/za/blog/animal-minds/202406/the-purpose-of-play-for-young-male-dolphins. Accessed 27 Mar. 2026.

Davies, James R., and Elias Garcia-Pelegrin. “Bottlenose Dolphins are Sensitive to Human Attentional Features, Including Eye Functionality.” Scientific Reports, vol. 13, no. 1, 2 Aug. 2023, article 12565. doi:10.1038/s41598-023-39031-7. Accessed 27 Mar. 2026.

Herman, Louis M. “What Laboratory Research Has Told Us About Dolphin Cognition." International Journal of Comparative Psychology, vol. 23, no. 3, 2010, pp. 310–30. doi:10.46867/ijcp.2010.23.03.07. Accessed 27 Mar. 2026.

Hof, Patrick R., and Estel Van der Gucht. “Structure of the Cerebral Cortex of the Humpback Whale, Megaptera novaeangliae (Cetacea, Mysticeti, Balaenopteridae).” The Anatomical Record Part A, vol. 290, no. 1, 2007, pp. 1–31. doi:10.1002/ar.a.20407. Accessed 27 Mar. 2026.

Janik, Vincent M., and Peter J. B. Slater. “Vocal Learning in Mammals.” Advances in the Study of Behavior, vol. 26, 1997, pp. 59–99, doi:10.1016/S0065-3454(08)60377-0. Accessed 27 Mar. 2026.

Jerison, Harry J. Evolution of the Brain and Intelligence. Academic Press, 1973.

Melzer, David K., et al. “A Comparative Test of Creative Thinking in Preschool Children and Dolphins.” Animal Behavior and Cognition, vol. 9, no. 3, 2022, pp. 349–62. doi:10.26451/abc.09.03.07.2022. Accessed 27 Mar. 2026.

Pack, Adam A. “Dolphin Social Cognition.” The Cambridge Handbook of Animal Cognition, edited by Alexander B. Kaufman et al., Cambridge University Press, 2021, pp. 383–414.

Reiss, D. The Dolphin in the Mirror: Exploring Dolphin Minds and Saving Dolphin Lives. Houghton Mifflin Harcourt, 2011.

Reiss, Diana, and Lori Marino. “Mirror Self-Recognition in the Bottlenose Dolphin: A Case of Cognitive Convergence.” Proceedings of the National Academy of Sciences, vol. 98, no. 10, 2001, pp. 5937–42, doi:10.1073/pnas.101086398. Accessed 27 Mar. 2026.

Reynolds, John E., et al. The Bottlenose Dolphin: Biology and Conservation. University Press of Florida, 2000.

Zeng, Ying, et al. “Bottlenose Dolphins (Tursiops truncatus) Display Gaze Alternation and Referential Communication in an Impossible Task.” Heliyon, vol. 10, no. 12, 17 June 2024, article e33192. doi:10.1016/j.heliyon.2024.e33192. Accessed 27 Mar. 2026.