Our Feelings. Why Do We Have Them? (2)

My previous article "Our Feelings" (Brain & Mind - November  2001-March 2002) was a suggestion about the role of feelings and emotions in the Darwinian Evolution Theory. It's a text of Neuroscience where I suggest the reason why feelings and emotions exist in our brains.

Doubts were expressed by several readers and for this reason  I've felt the necessity to develop this matter a little further.

To begin, we must understand  that there's a kind of order, an upward scale of complexity of living beings on our planet, from lowly unicellular life to worms, arthropods, reptiles, fishes, birds, mammals, primates and humans. Among all these, the main difference between us and the other animals is that we have the most complex nervous system. Except for this, our bodies are very similar, in genetics, physiology and biochemistry, to most of other mammals. It's important to bear in mind that increasing complexity doesn't necessarily mean that there is a corresponding "timeline" in the evolutive history of each animal group in relation to the others. For instance, a bird is more complex than an insect, but the latter may be younger as a species. A new species may even evolve to a lesser degree of complexity, in case ecological changes provide for it. Neurophysiologist Rodolfo Llinás, in his remarkable book "I of the Vortex" cites an example of a sea invertebrate which digests its own brain when it evolves from a free-moving worm in the ocean to a permanently attached barnacle.

Modern science has now proved without doubt that living beings evolve, or better, they modify, adapt themselves to changes in the environment. The so called "standard model" of biology has firmly married the discoveries of molecular biology, genetics and evolution. It is arguable that this applies to all aspects of our biology, including the basis for our most complex behaviors and emotions.

Biological evolution means that a permanent (gene-coded) change occurs in the form and functions of cells, tissues and organs of living beings. However, since Darwin's time, but especially due to the pioneering work of animal ethologists in the 1930's, such as Konrad Lorenz, we know also that behavior is also subjected to selective and adaptive pressures. Behavior "came into being" on Earth long ago. For example, an unicellular being such as an ameba is able to react to positive and negative stimuli coming from the environment by altering its movements, so as to assure its survival. These kinds of simple behaviors, such as tropisms, have probably existed for hundreds of millions of years and can be found even in organisms without nervous systems, such as plants. However, natural selection has continuously pressed for more and more advanced forms of behavior, which generated the evolution of sensory organs, muscles and specialized neural networks. In terms of behavior, it is equally valid the concept for morphological changes: the more varied is the spectrum of available behaviors, the highest are the chances for survival in changing environments. Diversity is the keyword here. Many theorists suggest, therefore, that brain complexity is essentially related to the complexity of behavioral strategies for survival of the species and to the rigors of competition. This is not difficult to imagine because organisms which have to aqcuire and process a greater amount of information on the environment require more complex nervous systems.

Eventually (and this was one of Darwin's main worries) all rational and emotional features of human brains, even exceedingly "higher" and complex ones, such as language, thought, logic, emotional feelings, etc., can be entirely explained by natural selection effects on evolution. Some authors, such as Richard Dawkins, go to the extreme lenght as to suggest that the essential feature of all life forms is to preserve the survival of genes ("The Selfish Gene").

In my first article I quoted an example of the bonding which appears between parents and children, and feelings such as affection, love, etc, without which none of us would be able to survive after birth. However, in many situations the drive to protect our younger ones conflicts with our own instincts for survival. At this point, my suggestion is that the brain's rational side becomes so important as its emotional side. Furthermore, reactions such as aggressiveness against predators and toward the defense of the social group as a whole may take precedence over the protection of youth, with a view to perpetuate the species, as we observe in many non-human primates, such as chimpanzees, where infanticide is common and related to the instinctual basis of these kind of defenses.

This is not so in human beings. Because of cultural evolution, this instinctual, emotional basis may be entirely subverted by reason. For instance, a mother may prefer to sacrifice her own life to save her baby's. Or the survival of an entire group may be threatened on the basis of purely rational decisions (such as in war). "Knowing" is rational, "feeling" is emotional, hence these are the two main pillars upon which all our behavior and conscience are based. We are both rational and emotional, these two spheres are unified and cannot be separated, as it has been beautifully explained by neurologist Antonio Damasio, in his book "Descarte's Error". Citing the seemingly lack of emotion in sociopathic personalities and the alterations of mood and behavior in brain-lesioned patients, such as in the historical case of Phineas Gage, Damasio goes on to explain that René Descarte's error was to suppose the separation between rational and irrational (emotion), and that being supremely rational was the best to Humankind. It is not: without emotion, rationality loses an important component and becomes pathological.

In conclusion, Nature found out a way to sort out the problem of living beings which have a family which depends on their genitors in their maturing period. The behavioral strategies which came out after millions of years of hominid evolution and sexual selection involves a complex mixture of reason and emotion. This is probably the basis of our uniqueness among all others species.

 The Author

Argos de Arruda Pinto Physicist  Email: argos@linkway.com.br Santa Rita do Passa Quatro SP,. Brazil. .