Sydney (LabNews Media LLC) – The brain reacts differently depending on the predictability of an event: During surprises, it directs energy toward absorbing as much sensory information from the environment as possible. In contrast, with expected events, it saves energy by processing them less deeply.
This is shown by a study from the University of Sydney, published in the journal The Journal of Neuroscience. The researchers, led by Dr. Reuben Rideaux and doctoral student Ziyue Hu, used EEG measurements, pupil responses, and behavioral tasks to investigate how the brain handles predictable and surprising visual stimuli.
“With a predictable event, the brain thinks, ‘I already know what this is, I don’t need to process it carefully,’” explains Rideaux. “With unexpected events, on the other hand, it’s like a software update: The brain wants to update its internal model of the world and therefore dedicates energy to gathering as much information as possible from the environment.”
The study shows that expected events are processed in two phases: an initial prediction and preparation, followed by rapid recognition. Unexpected events, in contrast, are depicted more clearly in brainwaves and lead to more vivid memories.
“We found the answer: The brain does both – it saves energy on the familiar and invests in surprises,” says Ziyue Hu. The entire process occurs within milliseconds.
The findings explain why surprising events are often particularly well remembered. They also have practical relevance, for example in competitive sports, where athletes can react quickly through predictions, but remember surprising situations with particular precision.
