In our previous conversation, we talked about how experiences contribute to shaping our understanding of what we go through. The importance of this constructive capacity becomes evident when we see its influence on our behavior. For example, in a situation where people could choose between a sweet or a bitter food, most would likely choose the sweet one, because generally, foods with that flavor promote a pleasurable experience; this preference occurs even in newborns and can be measured by the facial expressions of the baby provoked by each of these flavors (Steiner et al., 2001). It is important to remember that human decision-making involves various factors and is not limited solely to the pleasure generated; for instance, using the same example, we can imagine that some people would not opt for the sweet for health reasons, while others would simply prefer the bitter flavor. But the question now is: how can experiences determine our behavior?
The answer to this question lies in the modifications generated by learning. In the late 1960s, Eric R. Kandel demonstrated that even the simplest behaviors can be modified by learning. Later, the scientist discovered that this learning was accompanied by molecular changes and alterations in the strength of the synapses between the neurons that produced the behavior in question, and found that repeated training caused these modifications to be sustained over long periods, leading to long-term memory. Kandel observed that in the process of habituation (decrease of a certain response after repeated exposure to a specific stimulus) the number of presynaptic connections between the neurons involved in the response decreased, while in sensitization (increase of a response after the repetition of a certain stimulus) the opposite occurred, meaning new connections were formed that persisted during the time the memory was retained.
Today we know that experiences promote neuroplasticity, that is, adaptive neural modifications that strengthen, weaken, or create new neuronal connections. This is why practicing a skill leads to improvement; for example, when we perform an activity for the first time, like riding a bicycle, we generally do not succeed because we do not yet know the correct movements or the necessary speed and balance; however, each time we repeat the task, we strengthen the neuronal pathway responsible for its execution and become more skilled. In conclusion, we have seen that our nervous system is capable of undergoing modifications that reflect in our behavior; and this neural plasticity makes me reflect on what neural pathways we are strengthening at this moment. Could positive stimuli help us reinforce beneficial connections?
References
Steiner JE, Glaser D, Hawilo ME, Berridge KC. Comparative expression of hedonic impact: affective reactions to taste by human infants and other primates. Neuroscience and Biobehavioral Reviews. 2001; 25:53-74;
Kandel, ER. Even simple behaviors can be modified by learning. In: In Search of Memory – The Emergence of a New Science of Mind (Kandel, ER). 2009; p. 211-231, Companhia das Letras.
Kandel, ER. The biological foundations of individuality. In: In Search of Memory – The Emergence of a New Science of Mind (Kandel, ER). 2009; p. 211-231, Companhia das Letras.
