Memories: How the brain chooses which memories to keep or erase

Of the different stimuli that reach the brain every day, only some become permanent memories. The process is not random: the organism uses biological and psychological criteria to decide what to record in more depth. Emotions, level of interest, quality of sleep, and even stressful situations influence which episodes gain space in memory.

This selection occurs in stages. First, the experience is captured. Next, you have to strengthen yourself to last longer. Information that is considered of little importance is easily scattered because the brain prioritizes what contributes to learning and adaptation. This mechanism prevents overload and allows the system to continue focusing on what it considers most useful.

How the brain selects memories

To determine which memories are worth keeping, the brain uses some basic criteria. The first relates to emotion, where situations that elicit fear, intense joy, or strong emotional attachment activate areas associated with the subject. This increases the chance that the ring will remain a lasting memory.

Neuropsychologist Leninha Wagner, from Florianópolis, explains that the brain uses emotional and contextual cues to reinforce records.

“The brain prefers what speaks to our internal history,” he says. “Emotions, context, and repetition act as codes that tell us what is worth moving from the momentary record to the more stable memory.”

Another basic criterion is interest. When the focus is on a specific event, the brain organizes information better and consolidates memories. In moments of distraction, due to impulsivity, multitasking or excessive stimuli, memory formation fails and tends to be lost before consolidation.

In addition to these basic criteria, negative spells or those associated with risk tend to be stored for a longer period. In moments of stress, the body secretes substances that intensify the recording, leaving the memory marked with clear details. This mechanism was useful for avoiding threats in the past, but today it explains the persistence of difficult memories.

Areas of the brain associated with emotions and attention help determine which memories remain and which are lost over time

Memories can change over time

Memory does not remain the same as it was the day it was created. Whenever it is accessed, it goes through the update phase. The brain reopens the record, reorganizes the information and fills in the gaps with elements of the present. This process makes memories vulnerable to change, even when they seem very vivid.

Andre Sena Machado, a psychologist and member of the Regional Psychology Council in Rio de Janeiro, emphasizes that this flexibility is not a defect, but a trait that has accompanied the species since the first humans.

“Memory was born as an adaptation tool. In the unstable regions in which our ancestors lived, reconstructing parts of memory was more useful than keeping all the details constant. This mechanism helped to interpret new situations based on old experiences, even if accuracy was lost along the way,” Andrei highlights.

Habits that help strengthen memory

Certain behaviors enhance the process of turning experiences into lasting memories. An adequate night’s sleep gives the brain the time it needs to organize information and transfer it to more stable areas of the cerebral cortex.

Furthermore, repetition distributed over time helps establish connections between neurons, allowing content to be retrieved more easily. Reducing multitasking and digital stimuli also helps, as interruptions make consolidation more difficult and encourage fragmented memories.

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