Highly superior autobiographical memory

How it works

Give a person with HSAM a date, such as 14 March 2003, and they tell you the day of the week, what they did, what the weather was, and what was in the news. They answer in seconds and describe it as effortless. Many say the memories replay like a film they cannot switch off¹.

The ability is narrow. In standard laboratory memory tests, such as remembering word lists or strings of digits, people with HSAM score about the same as everyone else¹. It is memory for their own lives, not memory in general. They also form false memories at the same rate as other people when tested with standard suggestion tasks¹.

Brain scans show some differences in the temporal lobe and in the caudate nucleus, a region also linked to habit and obsessive-compulsive behaviour¹. Many people with HSAM describe obsessive traits, such as collecting and organising. Nobody knows whether constant reviewing of the past creates the memory or the memory creates the habit. It has not been trained in anyone. It appears in childhood and lasts for life¹.

How common it is

Researchers had confirmed about 62 cases worldwide by 2024¹. Confirmation requires passing a hard screening test of public events by date, so many people with the ability are probably unidentified.

History and culture

The first published case was Jill Price, known in the 2006 paper as “AJ”. She wrote to the memory researcher James McGaugh at the University of California, Irvine, in 2000, and his team studied her for years². The actress Marilu Henner has it and has described it on television³. The word hyperthymesia was coined for the first case. HSAM is now the usual name¹.