Double take: Scientists solve the mystery of “hyperfamiliar” faces
Posted on Tuesday 12 May 2026
For some sufferers of a rare condition called hyperfamiliarity for faces (HFF), this confusing and sometimes distressing reality can be an everyday occurrence.
Now neuroscientists at the University of York, in collaboration with Dartmouth University in the US, have uncovered exactly why this happens. By scanning the brain of a woman named Jenny - who developed HFF after a severe migraine - researchers have identified the neurological triggers behind the condition. The study provides a unique insight into how the human brain separates the simple act of seeing a face from the emotional spark of recognition.
The findings reveal that the condition is caused by an altered connection in the brain. While Jenny's visual systems and memory perform normally, the communication between the two has become hyperactive to generate a constant false alarm of familiarity.
Neuroimaging
To understand the mechanics of the condition, the York team used neuroimaging to monitor Jenny's brain activity while she watched clips of the television series Game of Thrones. Crucially, Jenny had never seen the show before.
They compared her results to two groups: people who were devoted fans of the show and those who were entirely unfamiliar with the characters. The results revealed that even though the faces were completely new to her, the activity in Jenny's hippocampus (a region of the brain vital for memory) closely mirrored that of the long-term fans.
Powerful signal
Professor Tim Andrews, senior researcher from the Department of Psychology at the University of York, said: “Our findings show that Jenny's basic face-processing system is perfectly intact. She can see features and recognise her own family and friends without any issues. Her basic vision is also normal. The problem arises because the communication between her visual system and her memory system has become exaggerated. Her brain is essentially sending a powerful signal that she knows a person when it should be silent.”
The study suggests that the sense of familiarity is not a single process but a result of a dynamic interplay between the visual parts of the brain and the medial temporal lobe. In people with HFF this connection is altered.
Understanding these brain mismatches could eventually lead to better diagnostic tools for broader memory disorders and conditions like Fregoli syndrome where patients believe strangers are actually acquaintances in disguise.
Fundamental social experience
Dr Kira Noad, the lead author on the study and a former PhD student at the University of York added: “Jenny describes the experience as both confusing and distressing. It highlights that the feeling of knowing someone is a distinct neurological track from actually knowing who they are. In HFF these two tracks become uncoupled.
“By studying this rare imbalance we are advancing knowledge of how all our brains navigate social interactions and create one of our most fundamental social experiences.”
