The mind wags the dog

The brain wags the dog in the cerebrum - which is seen as consisting of two similar halves (the hemispheres) - a functional asymmetry is revealed, partly in terms of emotions. In dogs, it turns out, this is also expressed in the direction of the tail

Zvi Atzmon

Photos: Galileo system

Looking externally at the brain of a vertebrate, one can get an impression of the symmetry between its right and left parts, a symmetry that actually reminds of the external appearance of the body, since many of the internal organs are arranged in a striking asymmetry (and see: "Right and left - only a garden can", "Galileo" 48) . This symmetry has an undeciphered side - the famous crossover between the side of the body and the world on the side of the brain: the left side of the brain mainly controls the actions of the voluntary muscles on the right side of the body and vice versa. Also, except for special cases (like the sense of smell), the right side of the brain receives sensory information from the left side of the body and the world, and vice versa.

The symmetrical (albeit crossed) conception of the brain was cracked in the 19th century. The studies of Mark Dax, Paul Broca and Carl Wernicke indicated that the left hemisphere of the brain is related to speech and speech decoding. This means that despite the symmetrical appearance, the hemispheres of the cerebrum are not symmetrical in terms of their functions and properties. This fact is partly related to the fact that a person has one hand which is the "dominant" hand, the hand that "does the work". In most people (those whose dominant hand is right), the left hemisphere is the one that activates the "dominant hand", and since in the vast majority of people it is also involved in the production of speech and deciphering words and grammar, it used to be called the "dominant hemisphere".
However, there are many abilities in which the right hemisphere actually excels (for the avoidance of doubt, it should be noted that this refers to the vast majority of human beings; there are people in whom the organization of the hemispheres is reversed or less distinct). Evidence indicates that the left hemisphere has an advantage in serial analysis of information (such as the series of words in speaking, reading), while the right hemisphere has an advantage in holistic perception, such as perceiving images and XNUMXD structures and recognizing faces. There is also evidence that the left half has an advantage in logical analysis, as well as in providing an interpretation, while the right half has an advantage in perceiving social and emotional situations. Thus, for example, the right half is more important in recognizing faces, as well as in recognizing (and performing) the intonation of speech (indicative vs. question, for example, or direct vs. ironic). It is also claimed that the left hemisphere is "conservative" while the right hemisphere is constantly updated, for example in relation to the state of the body and its abilities (therefore, paralysis due to damage to the right hemisphere may manifest itself in "disease denial", anosognosia).



Does the dog say about his beloved owner "he understands almost everything, he just doesn't notice the angle of the tail"?

It also seems that the left hemisphere is engaged in a systematic search for solutions, while the right is more important for the "brightening" solutions (see: "Eureka - lightning in the brain", "Galileo" 83). And what is more relevant to our story here - the right hemisphere is more pessimistic, while the left is optimistic. This is partly reflected in the fact that people who have had a stroke that damaged the right hemisphere of their brain are in many cases more optimistic than people who have had a corresponding injury to the left hemisphere of their brain.

The fact that different skills characterize, at least relatively, the two hemispheres of the brain is known as lateralization (or hemispheric specialization; and see: Gita Ben-Dov - "Time, Space and the Hemispheres of the Brain", "Galileo" 56). For a long time, hemispheric specialization was attributed to man only, partly because the linguistic ability (language skills) of man reveals a distinct lateralization.

And by the way, in this case the lateralization is not only functional - a careful examination revealed size differences between the area responsible for decoding speech in the left half of the cerebral cortex (an area known as the planum temporale) and the corresponding area in the right half of the cerebral cortex. The size differences are so evident that attempts have been made to identify the beginning of human speech in ancient hominid fossils based on the marks left by the sacral surface of our ancestors on the inside of the skull.

The notion that lateralization is a unique human trait was abandoned as evidence of lateralization in the brains of other animals increased. Thus, for example, it turned out that among chimpanzees - as among humans - the facial expressions that reflect emotions are more prominent in the left half of the face (which is mainly affected by the right hemisphere). Excited chimpanzees scratch their left torso precisely - another evidence of lateralization. And sheep - which are good at distinguishing between the faces of other sheep - do this mainly through the special abilities that characterize their right hemispheres (also similar to humans).

The greater involvement of the right hemisphere in the identification and processing of emotions is particularly noticeable when it comes to negative emotions. Perhaps this is one of the reasons why the left side of the body (that is, the right half of the brain) was suspected and slandered in many cultures, and that Shaitars suffered from bad treatment, which in certain circumstances reached the point of oppression and persecution. In many languages, words indicating right are close to, or identical to, words indicating proper, appropriate, fair (for example, in English - right), while words indicating left are close, or even identical, to words indicating bad, sometimes dangerous, even satanic qualities; For example, the Latin word sinistra and its various European derivatives.

In terms of the behavior of animals, it is accepted among researchers that the left half of the brain deals with approaching and storing energy, while the left deals with moving away and expending energy. In humans, an expression of this is greater activity in the left hemisphere when you feel a sympathetic and loving environment, closeness and security; Under these circumstances, the body's maintenance systems are activated, filling its reservoirs. On the other hand, dangerous situations instill a feeling of fear, in which the right hemisphere works more. Dangerous situations increase the heart and breathing rate, stop the building and maintenance processes (such as digestion) and increase the tendency to spend energy to escape.


Even staunch dog lovers will probably be surprised by the fact that not only the wagging of the tail, its strength and pull, indicate the dog's mood, but also the direction of its tilt. Illustration: Rose Nimrod

Dog owners - and perhaps better: people who have canine friends - know very well the mood of the one walking on all fours next to them (and of course - also the other way around). However, even die-hard dog lovers will probably be surprised by the fact that not only the wagging of the tail, its strength and pull, indicate the dog's mood, but also the direction of its tilt. At least this is what Giorgio Vallortigara, a neuroscientist from the University of Trieste in Italy, and two veterinarians from the University of Bari, Angelo Quaranta and Marcello Siniscalchi, claim in an article they published in the journal Current Biology (and see : for further reading). From the findings they present, it appears that when the dog is excited and feels a positive emotion, such as joy and security, the tail wags more to the right when wagging, while when a negative emotion, such as fear or dissatisfaction (this is at least a possible interpretation, see below), the tail wags more to the left. This means that the muscles that move the tail to the right are activated more in circumstances of joy and a sense of security; And remember that these muscles are activated by the left half of the brain. In circumstances of fear, apprehension, and perhaps embarrassment, the right half of the brain is activated more, and it mainly activates the muscles that move the tail to the left.

Velortigra and his fellow veterinarians examined the relationship between the angle of the tail and external stimuli in 30 dogs whose owners volunteered them for the experiment, all "mixed" house dogs. During the experiment, the dog was kept (for a few minutes at a time) in a cell with video cameras, aimed at documenting the angle of the tail. The cage had a peep hole that opened for one minute, during which the dog saw its beloved owner, a stranger, a friendly stranger cat, a fearful (Belgian Shepherd) stranger dog, or during the minute of exposure nothing was seen. There was a 90 second break between exposures.

In the analysis of the videos, it became clear that when the dog saw its owner, its tail wagged vigorously. What gentlemen - this find has been known, obviously, for thousands of years. However, the novelty is that under these circumstances the angle of tilting the tail to the right (using the muscles in our right hand, operated by the left hemisphere) was greater than the tilting to the left. The kashkush was more right-handed even in the presence of a person who is not the owner, although the power of the kashkush was then lower, befitting a loyal friend. Even in the presence of the lovable cat when the dogs crawled more to the right, although the intensity was even lower. It can perhaps be concluded that the sight of the lovable cat caused excitement, but a relaxed excitement, that of the left hemisphere. On the other hand, when the subject discovered in front of him a fearsome and unfamiliar Belgian shepherd, he wagged his tail with a clear tilt to the left - evidence of a great activation of the right hemisphere. When the peep hole was opened and nothing appeared, when the dog swung (out of anticipation?), and also in this case with an excessive tilt to the left. Is the embarrassment due to an unfulfilled expectation? Or from a feeling of loneliness? - This was not addressed by Valortigre and his colleagues in their article.

Dog lovers often say that "he understands everything, it's just a shame we don't know how to talk". Does the dog say about his beloved owner "he understands almost everything, he just doesn't notice the angle of the tail"? In truth, the angle differences found by Valortigre and his colleagues are so small that they cannot be discerned by the eye (at least by the human), except by precise measurement in video films.