I suggest that we think more in terms of a physiologically appropriate set of more general mechanisms which may subsume several other human functions under the same principle. It seems to me that we must look for abilities to develop generalized dexterity of use for certain kinds of end purposes for any or all muscular outputs from the central nervous system. If there is a task to be done, such as lifting a stone, whether in water or air, a given animal may turn it over with his foot, with his flipper, with his hand, with his tail, or with any other body part with which he could obtain a purchase on the stone. The end task is turning over the stone, to obtain food or whatever. It makes little difference what kind of muscular equipment he uses just so he uses it appropriately.
Let me illustrate with a more complex example seen in our own laboratory. A baby dolphin was being nursed in a small tank artificially. It apparently needed the constant attention of a human attendant. Its mother had not been caught with it. After several days it discovered that if it banged on the bottom of the tank with its flipper in a rhythmic fashion it could bring the humans from the other room. (We heard a loud thumping sound transmitted from a hydrophone in its tank.) Previous to this it attempted to bring the humans from the other room by whistling the distress call of the dolphins; unlike its mother, the humans did not respond to the whistle. In a sense this distress call is in his instinctual pattern for obtaining food and aid by other dolphins. The secondary adaptation and the new effort was that of manipulating the flipper rather than the phonation mechanism in the blowhole. Thus driven by whatever the instinctual need is, it tried different outputs from its brain and finally discovered one which brought the desired results. This ability to change the output from unsuccessful ones to successful ones seems to me to be evidence of a “higher nervous system” function. Of course in fine gradation and small differences, the same kind of pattern can be shown for smaller-brained animals. It is the seeking a new output, not necessarily instinctually tied in, and the radicalness of the change of output, plus the relating of many of the variables to one another thus generating the new output, that seems to be the hallmark of the large brain. These problems are not single variable ones with simple cause and effect, but are simultaneous multiple variable ones.
Among the manipulable outputs (muscular groups) I would include those of respiration and phonation. The dexterous and finely differentiated use of these muscles generates all the complexities of human speech. As more of the physiology and psychology of human speech are analyzed and made part of our sciences, the sharper will be our criteria for separating man from the other animals, and from those with smaller brains. Scientific descriptions of human speech are of relatively recent origin. Scientific descriptions of the physiology of the vocal tract are anything but a closed book at the present time. The neuroanatomy and neurophysiology of speech is in a relatively primitive state of development as a science. With such a lack of knowledge of the intimate and detailed mechanisms concerned, it would be rather presumptuous to evaluate at the present time their role in the measurement and testing of intelligence and intellectual capacity.
However, I wish to point out that these factors are important in such an evaluation and become even more important in terms of evaluating a species that is not human. Thus it is necessary, in order to evaluate the intelligence of even the dolphins, much less the whales, to know something of their abilities in the areas of phonation and other kinds of bodily gestures and manipulations and hence in their abilities to communicate with one another. As I implied in Man and Dolphin, it is not possible to measure accurately the intelligence of any other being than that of a human being, mainly because we do not exchange ideas through any known communication mode with such beings.
The difficulties of such understanding as we can possibly gain of the real situation of the whales in the sea and their adaptation as mammals to this particular environment, can be illustrated by their use of sonic generators for the location of their prey and of the boundaries of their container by means of the perception of echoes. As is well known, the small mammals, such as the bat, use this mechanism in air.[9] The bottlenose dolphin also uses this same kind of mechanism underwater.[7][9][10] Because these animals are immersed in a medium of a density and a sound velocity comparable to the density and sound velocity of their own bodies, they can presumably use their sonar also in looking, as it were, inside one another’s body.[7] The sonar view of the inside of the body of a dolphin may possibly be very instructive to other dolphins and possibly even aid in diagnosis of the causes of certain problems, especially of those of the baby by the mother. For example, their buoyancy depends upon maintaining their center of gravity below their center of buoyancy; otherwise they turn over and drown. If the baby develops gas in stomach #1, he can develop problems in his buoyancy relationship which turn him over; however, the mother dolphin can probably easily find out whether or not there is a bubble of gas in the baby’s stomach by her echo ranging abilities. When she discovers such a bubble, she can then burp the baby by banging on the belly with her beak. We have seen such operations take place in our tanks. Here is another instance of the animal using a given output, coupled with the proper input, to diagnose a problem and to manipulate other outputs in the solution of that problem. How much of this is labeled “instinctual,” i.e., “unlearned,” is purely a matter of intellectual taste.
In the sea it is necessary to use sonic mechanisms for sightings and recognition. If one goes into the sea one realizes that one’s range of vision even under the best of circumstances is rarely beyond 100 feet and most of the time is less than that even near the brilliantly lit surface of the tropical seas. With sonic means, one’s range is extended up to several miles under the best of circumstances and under the worst to a few hundred feet.
Recently we have obtained evidence that shows that the dolphins communicate most of their information in the band of frequencies extending from about 8 kilocycles to 20 kilocycles by means of whistles and sonic clicks.[11] However, as shown by Schevill and Lawrence, they can hear sounds at least to 120 kilocycles[12] and as shown by Kellogg can produce sounds at least to 170 kilocycles.[10] We have recently been investigating the higher frequency bands in these animals and have reliable evidence that they can hear at least to 200 kilocycles and can produce sounds to at least 200 kilocycles.[7][13] With the proper electronic equipment one can listen to the nearer portions of the upper band and quickly determine that they can transmit in these bands without the necessity of transmitting in the (lower frequency) communication band. The high frequency information is broadcast in a narrow beam off the front of the beak as was first detected by Kenneth Norris.[14]
In these bands we find that they can produce musical tones or individual clickings or hissing-like noises. Recently we have found that an emotionally upset animal threatens other animals and humans by productions of very large amounts of energy both in the sonic communication band and in the ultrasonic bands. Recently we have had the opportunity of working with an old bull of 450 pounds weight who is so old his teeth have been ground down flat. In terms of his skeleton, he is the most massive animal we have ever seen. When he is irritated, his “barks” have sizable amounts of energy from about 0.5 to at least 300 kilocycles. He is also capable of transmitting in bands between 100 to 300 kilocycles without transmitting anything in the band from 8 kilocycles to 20 kilocycles in a narrow beam straight ahead of his body. When he is upset by the activities of a younger male, they face one another and blast at one another with short barks of this sort, meanwhile “threatening” by opening their mouths.
Since they live immersed in an acoustic world quite strange to us, we have great difficulty in appreciating the full life of these animals with respect to one another and their environment. From birth they are constantly bombarded with signals from the other animals of the same species and by echoes from the environment which they can apparently use very efficiently. Their ultrasonic (to us) emissions are not merely “sonar,” but are interpersonal and even emotional. These animals are not inanimate, cold pieces of sonar apparatus. They use their ultrasounds and their high-pitched sounds interpersonally with fervor in everything they do.[15]
We have demonstrated that the dolphins are quite capable of using vocal outputs as a demand for further rewards or for surcease from punishment. Their ability in the vocal sphere is quite sophisticated. In addition to the ultrasonic matters mentioned above, their sonic performance, when in close contact with man, is astonishing. In 1957 I discovered their ability to produce sounds similar to our speech sounds.[16] During the last two years we have had many opportunities to pursue further observations in this area. This emerging ability seems to be an adaptation to a new environment which includes Man.[17] They quickly discover that they can obtain various kinds of rewards by making what we now call “humanoid emissions.” When they make a sound which sounds similar to a human syllable or word, we express our pleasure by rewarding the animals in various ways. We have been exploring what some of these rewards are in order to elicit further such behavior under better control.