The relationship between brain and behavior seems to be the successor of the famous Cartesian mind-body dualism, where the brain is the physical or biological component and behavior the mental or psychological aspect.
Despite its ancient origin, the body-mind dichotomy continues to be an unresolved problem nowadays. Both concepts have been kept apart as if they were separate and distinct.
However, the idea that the mind and body function separately turns out to be an impediment to scientific progress, since mind and body are related in a more complex way than one might imagine.
Why do we behave in a certain way? Is the brain in charge of our actions?
Try to answer the following question:
What is our brain’s ultimate goal?
Many people will respond:”to perceive, think, reason, or learn.”Even if it is true that the brain performs such tasks, all of them serve as the basis for an ultimate purpose: to direct behavior. For example, through our perception we can know what is happening in our environment, thereby triggering more useful and adaptive behaviors.
The goal, then, is to relate specific brain events to certain behaviors. However, everything is not so simple. For example, the same behavior can be triggered by different physiological mechanisms: we can drink a beer because we are thirsty or because we feel stressed and want to take advantage of its intoxicating effect.
Are we our brain?
Now, try to answer the following questions:
If you could transplant Einstein’s brain into your body, would you think and talk like him? Would you behave exactly like him? Would you have won the Nobel Prize in Physics?
What if Mozart’s brain was transplanted into your body? Would have you composed the same number of pieces as he did?
The first thing we tend to think is that if we had the brain of a genius, we would be the genius, since we think the brain is responsible for our behavior. However, this matter becomes increasingly complicated.
We must not forget that the brain is flexible and has the ability to change. This organ evolves throughout life and adapts to the changing environment. Thus, the relationship between brain and behavior is modulated by different factors:
- The environment: our environmental surroundings influence our brain and behavior. For example, the environment modulates the development of different skills. Therefore, language acquisition can vary for a child coming from a rural area to another from an urban area (because the verbal stimulation that each one receives is different).
Another example is that of enrichedenvironments. It is scientifically proven that individuals raised in enriched environments have a greater number of synaptic connections among neurons (since an enriched environment providesindividuals with possibilities for action and increases cognitive and sensory stimulation) than those in impoverished environments.
Additionally, there are environmental factors that can influence the development of the nervous system. One example is malnutrition in early life.
Therefore, it is demonstrated that our brain can undergo changes due to the environment, therefore influencing future behaviors.
- Sociocultural and historical aspects: returning to the example mentioned earlier on brain transplant, our behaviors might have been very different from those of geniuses in their time. We would have quickly adapted to our socio-cultural and historical context, undoubtedly different from that of Einstein and Mozart.
- Phylogeny: the human brain has a phylogenetic history, that is, inherited species characteristics. Thus, in the human brain, three distinct layers can be distinguished: a deep or reptilian layer (the oldest phylogenetic layer), an intermediate or limbic layer, and an outer or neocortex layer (which distinguishes humans from other animals). Thus, as we evolve as a species, the brain undergoes changes to meet the specific demands of the environment.
- Genetics:the development of our brain is governed by gene expression. To a certain degree, it can create variations such as different sensitivities to reward, different probabilities of emitting behaviors, etc. On the other hand, if there is a mutation in the genes, the process will vary and may cause different disorders.
- Ontogeny: refers to the development of the individual and to what we have learned throughout life. Our current behavior is determined by past experiences. These are stored in our memory and serve as a guide to emit certain behaviors and not others. One example is that, if we have experienced pleasure with an activity in the past, we tend to repeat it.
Another aspect that reinforces the brain-behavior relationship is the behavioral changes observed after brain injury. In fact, neuroscience is responsible for seeking links between specific brain structures and certain behaviors, mainly through the observation of brain-injured individuals. Thus, neuro imaging techniques are used to determine the lesion site and the neuropsychological profile of the individual is examined. If the pattern is repeated in a large number of patients, it can be said that a specific brain area is associated with the impaired function.
In short, all this indicates that there is a complex and interdependent relationship between the brain and behavior. The brain receives information and internal and external influences that enable the most appropriate behaviors to be triggered at any time. In addition, our behavior has environmental consequences, which can be experienced as positive or negative for us. These consequences make us learn and reduce the likelihood that that behavior will occur again in the future. Such learning out come send up producing brain changes, in particular in brain synaptic connections.
– Carlson, N.R. (2006). Fisiología de la conducta 8ª Ed. Madrid: Pearson. pp: 2-3.
– Matute, E. y Roselli, M. (2010). Neuropsicología infantil: historia, conceptos y objetivos. En S. Viveros Fuentes. (Ed.), Neuropsicología del Desarrollo Infantil (pp. 3). México: El manual moderno.
– Tamayo, J. (2009). La relación cerebro-conducta ¿hacia una nueva dualidad? Revista Internacional de Psicología y Terapia Psicológica, 9(2), 285-293.