Why Your Brain Finds Some Objects Impossible to Forget

Have you ever wondered why a picture of a bicycle might stick in your mind longer than a photo of a generic chair? Vision scientists contend that objects carry an intrinsic property known as ‘memorability’—a metric describing the likelihood that an item will be successfully encoded and later retrieved. While earlier work suggested this property is supported by semantic information, the specific neural mechanisms remained largely unexplored until now.

To investigate this, researchers combined three distinct datasets: feature norms for approximately 1,000 natural object images, conceptual and perceptual memory data, and neuroimaging data from an fMRI study using a subset of 360 images. This multi-layered approach allowed the team to analyse how the brain responds to objects with varying levels of memorability.

The study found that memorable objects elicit consistent brain activation across different participants in key mnemonic regions, specifically the hippocampus and the rhinal cortex. Crucially, the variance in this neural activity is mediated by semantic factors—the descriptive meaning behind the images. The authors propose that the specific features of memorable images facilitate memory formation by engaging the brain's encoding processes more deeply. In short, the semantic richness of an object acts as a catalyst for the brain’s filing system.