Australian researchers have discovered new details about how the human brain processes predictable and unexpected events, helping to shed light on one of the most debated questions in neuroscience: how the brain allocates its resources to respond to the environment efficiently.
The study, led by scientists from the University of Sydney and published in The Journal of Neuroscience, concluded that the brain adopts distinct strategies depending on whether it faces familiar or surprising situations.
According to the researchers, when an event is predictable, the brain anticipates it and preps the appropriate response, allowing for faster reactions and energy savings. However, this information is processed with less detail, which explains why we tend to remember routine events less well.
In contrast, when confronted with unexpected situations, the brain redirects more resources to gather sensory information from the environment. This mechanism enables the formation of more precise and detailed memories, updating the internal models we use to interpret the world.
“The brain is constantly under pressure to make decisions and process enormous amounts of sensory information. Therefore, it seeks to conserve energy whenever possible,” explains Reuben Rideaux, a psychologist at the University of Sydney’s School of Psychology and the senior author of the study.
According to the scientists, this process works like a software update: when something unexpected arises, the brain invests more energy to understand the event and to better prepare for future situations.
The investigation involved 40 participants who watched visual stimuli while researchers recorded brain activity using electroencephalography (EEG) and monitored pupil dilation. At certain moments, the expected patterns were unexpectedly altered.
The results showed that participants reacted more quickly and with greater accuracy to predictable stimuli. However, when asked to recall the exact location of these stimuli, performance was worse than that observed after unexpected events.
The researchers further found that the brain processes predictable events in two stages. First, it anticipates what will happen and prepares a rapid response. Then, upon confirming that the prediction was correct, it reduces the effort devoted to detailed information processing.
The team concluded that both expected and unexpected stimuli are represented in the brain in about 100 milliseconds, but surprising events leave a stronger and more detailed neural trace.
The authors believe these findings could contribute to a better understanding of attention, learning, and memory mechanisms, as well as inspire new applications in artificial intelligence systems and artificial neural networks, making them more efficient at information management.
