It may depend on how hard the brain has to work, according to a study.

To understand, researchers at Yale University in the US explored visual information that is memorable "by pairing a computational model of scene complexity with a behavioural study".

The findings reported in the journal Nature Human Behavior showed that the brain may not remember a predictable event.

"The mind prioritises remembering things that it is not able to explain very well," said Ilker Yildirim, Assistant Professor of Psychology in Yale’s Faculty of Arts and Sciences.

"If a scene is predictable and not surprising, it might be ignored."

The team designed a series of experiments in which people were asked if they remembered specific images from a sequence of natural images shown in rapid succession. They found that the harder it was for the computational model to reconstruct an image, the more likely the image would be remembered by the participants.

"We used an AI model to try to shed light on perception of scenes by people - this understanding could help in the development of more efficient memory systems for AI in the future," said John Lafferty, Professor of Statistics and Data Science at Yale.