Dolphin Psychology

Type of psychology: Comparative; Cognitive; Developmental; Experimental; Social psychology

It is clear that dolphins, as well as many mammals, can be trained to portray a behavior when given certain conditioned stimuli. But how much deeper and through what situations and conditions can their intellectual abilities apply? Observations and experiments are unlocking the cognitive abilities of the cetacean mind. Tests on self-awareness, ability to comprehend complex sentences and inferential reasoning skills provide insights into the psychology of the dolphin brain. By studying these complex processes, we gain understanding of how non-human intelligent species, like dolphins, mental processes truly work.

Introduction

Animal cognition researchers utilize a ratio of body size to brain size called the encephalization quotient, or EQ. Because larger animals would ordinarily have larger brains and small animals smaller brains, the EQ is universally used to identify species where the ratio is suggestive of disproportionately large brains for an animal's typical size. Wherever the EQ is high, scientists infer superior intelligence. While humans have the largest EQ, many species of cetaceans, the family group to which dolphins, porpoises, and whales belong, have high EQs. The common bottlenose dolphin, tursiops truncatus, is perhaps of greatest interest because it has evolved an unparalleled brain mass relative to its body size. While humans have an EQ of 7.0, bottlenose dolphins, along with four other delphinidae (dolphin) species, have EQs ranging from approximately 4.1 to 5.0; these are ratios significantly greater than those found in any of the anthropoid apes. Of the delphinidae, the bottlenose brain is of special interest because the cerebral cortex, where thought processes occur, has the most convoluted and circuitous pattern of any animal, including humans. This area is a blood-rich, highly oxygen-dependent, and highly complex brain formation that invites scientific inquiry. It is clear to scientists that bottlenose dolphins think. What is intriguing is that there may be particular, individual dimensions of thought, the way certain incoming data is processed, for example, that may exceed human capacity.

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 other ones. This creates the need to communicate with potentially new pods or reunite with previous ones. To make these connections and address one another, dolphins have developed ways of identifying themselves and others. This labeling is what scientists have termed signature whistles. Signature whistles are individual specific calls that are emitted during separation as well as introduction to new individuals. This adaptation to make 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 must learn to use another's whistles and model theirs accordingly. One study done on six calves in Sarasota Bay gave 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. This makes sense because it differentiates the types of signature whistles in one area and helps identifying others to be more salient. Thus, calves display the ability of vocal learning. This ability evidences that dolphins hold a mental representation that is coupled with the whistle given.

The ability to identify other individuals by signature whistles is a novel adaptation, and studying pods over time can show their ability of 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 15 and sometimes 20 years, despite the amount of time they were associated. The ability of long-term recognition could potentially help dolphins recognize other individuals and help with admitting new members to groups within their fission-fusion society. Comprehension, reasoning and manipulation

Much of what is known about dolphin's comprehensive abilities comes from the ground-breaking research of Louis Herman. He conducted multiple studies to explore a dolphin's range of 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 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 semantically sound 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 on the bottom of her pool. So she spontaneously manipulated the hoop by bringing it upright and swimming though 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 bodies in order 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, was able to understand the concept of creating and when given the signal came up with 72 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 have the ability to invent things in their own mind and display their ideas.

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 15 months of age, 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 evolutionarily cannot point, it has been found through experiments that they can understand the idea of 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 12 test trials, three dolphins were able to perform above chance in touching the correct object and the other six reached significance by their 18th trial. Thus, evidence suggests that dolphins can readily understand a dynamic pointing gesture. To test head gazing cues, Tschudin used the same set up and instead of pointing used his head to show the dolphins where the object was. In the first 12 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 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 in which the dolphin would need the assistance of a tool or human to open. Spontaneously, the dolphins fixed themselves in front of containers and using their rostrums, or their mouth area, began a signal at the object. This behavior only occurred if divers were present so it can be interpreted as the dolphins' version of pointing. Not only is it intriguing that they were able to 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 body positioned toward the goal object. It occurred when divers were far from the dolphin or the object was far, not when the dolphin and diver were close. Monitoring shows that the dolphin is waiting for the attention of the diver and can actually infer the diver's attention. This theory-of-mind capability, the idea that one can interpret the mental state of another, can be explored in a follow-up study by Xitco et. al. Dolphins were notably able to employ monitoring and pointing behaviors when the diver was face forward. Dolphins may use body position and the direction someone is looking to infer where his or her attention is focused. Not only can dolphins understand human points but they can 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 who is face toward the dolphin and thereby inferring where the diver's attention is according to body positioning. This ability to think outside of one's self 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 and separated us from all other animals. This level of consciousness portrays 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% of the time in showing different body parts and 68% of the time using different body parts to complete tasks never presented to her before. Furthermore, there is evidence that she can recognize some ownership and agency over her body and how it moves and has a sense of her own body-image. Never before was she exposed to having labels for each body part. By 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 has 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 of 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, like other animals do under the belief it is another animal. But instead for a significant amount of the trials, their first action was a self-directed behavior in order to view the marking. When the mirror was present and uncovered, dolphins spent more time than in any other of the conditions 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 of it.

Bibliography

Herman, L. (2010). “What Laboratory Research Has Told Us about Dolphin Cognition." International Journal of Comparative Psychology, 23(3), 310–330.

Melzer, Dawn K., et al. "A Comparative Test of Creative Thinking in Preschool Children and Dolphins." Animal Behavior and Cognition, vol. 9, no. 3, Aug. 2022, pp. 349-362, DOI: 10.26451/abc.09.03.07.2022. Accessed 1 Feb. 2023.

Reiss, D. (2011). The Dolphin in the Mirror: Exploring Dolphins Minds and Saving Dolphin Lives. Boston, MA: Houghton Mifflin Harcourt.

Reynolds, J., Wells, R., & Eide, S. (2000). The Bottlenose Dolphin: Biology and Conservation. Gainesville, FL: University Press of Florida.