Why do we remember some things and forget others?

Why do we remember some things and forget others? Reward motivation seems to be key in learning. A priori, it may seem like a simplest question. But if we try to respond accurately we will realize that perhaps the answer is not so simple. What did we do a week ago at this moment? Are we able to remember it at the moment or should we strive? But surely we can easily remember marked dates such as a birthday, a wedding, the last approved one that gave us a university career, etc.

Content

• Why do we remember some things?
• Memories and rest
• Experiment
• Results: Reward motivation
  • Bibliography

Why do we remember some things?

If we leave aside neurodegenerative aspects and brain injuries, an interesting issue in a healthy brain is The reason we remember some events and forget others. If we go dinner with a friend or friend and have a really good time, that moment is going to stay in memory for much longer than other dinners with other people or with the same person in which we have not had a great time so well. What does it depend on that we remember it for a longer time? As the reader could intuit, he influences it well and living a pleasant (or painful) experience, but an investigation has shed light on a fundamental aspect: the motivation of reward.

From the University of California they investigated this phenomenon and published the results in the article Post-Learning Hippocampal Dynamics Promote Preferental Retention of Rewarding Events (2016) in the magazine Neuron. One of its main conclusions is that our brains take more into account pleasant memories when accompanied by a reward that modulates motivation. So this, along with other variables that we will see more depth, can be one of the reasons why an event is more clinging to memory.

Memories and rest

Memory needs to select memories, since if we remembered absolutely everything, the safest thing is that we would end up exhausted. Therefore, and as highlight from the Department of the University of California, during our rest moments, The brain filters the information that it considers most important to obtain rewards in the future. In this way, decide what to remember. Charan Ranganath, one of the researchers, says that the brain tends to give more priority to memories that will be useful in future decisions.

Experiment

To get to this conclusions, the researchers carried out an experiment. Through functional magnetic resonance they analyzed the brain of volunteers When they answered simple questions and not. For example, they were shown an object on a screen and asked if the object that appeared was heavier than another. Each object was shown with a background image to contextualize it. At this point, volunteers were told that if in a given context they responded correctly they would receive a large or small economic reward.

For example, if they succeeded in a context A, they received a good reward; But if they rightly right in context B, the reward was lower. At the end of a series of objects, volunteers were communicated to the total money. When the volunteers end this part of the experiment, brains scanned during rest time. However, and once the scan was finished, something that the volunteers did not expect was a surprise test of memory of all the objects that had been shown.

Results: Reward motivation

What the researchers observed was that the volunteers remembered better The objects that were associated with great rewards. Moreover, they not only remembered the object, but the background scene, that is, the context in which the object had been presented. Apparently, during the rest moments, the volunteers reproduced the most pleasant memories and that more profits had produced, in this way, reinforced the neuronal connections with which the establishment of the memory was strengthened. That is, the motivation for reward helped them establish some memories and not others.

As stated in the study, the results "suggest that the neuronal dynamics after learning could be a mechanism by which The brain prioritizes the retention of events that lead to rewarding results"(Authors, 2016). In addition to this, they establish an interaction relationship after learning between the ventral tegmental area (ATV) and the hippocampus. In functional magnetic resonance it was observed that these areas are activated and prioritized the retention of motivating information on less relevant information.

It is important to highlight at this point, that the ventral tegmental area belongs to the reward and reinforcement system, so it generates dopamine when something is pleasant to us. In this way, the behavior is reinforced so that it is produced again in the future. Thus, the interaction between the ATV and the hippocampus is reinforced when the motivation of reward is greater, so Memories associated with this reward are established more strong than others less relevant.

Bibliography

• Gruber, m., Ritchey, m., Wang, Shao-Fang, Doss, M., and RANGANATH, C. (2016). Post-Learning Hippocampal Dynamics Promote Preferental Retention of Rewarding Events,  Neuron, 89 (5), 1110-1120.