Human memory is delicate, and it tends to blur with time. Yet a very small number of people around the world carry an exceptional gift: the ability to recall the everyday events of their past with perfect clarity. Researchers have recently identified this rare ability in a 16-year-old boy, describing it as highly superior autobiographical memory (HSAM), or hyperthymesia. The findings, published in the journal Cortex, keep the teenager's identity confidential, referring to him only as KCL.

According to the researchers, KCL can recall events from his childhood with remarkable accuracy and detail, including moments from when he was just three months old. His parents have verified the truth of these early memories and say his conscious memory grew noticeably stronger from the age of three. A particular scent, a song, or even a short phrase can bring his memories flooding back involuntarily.

Researcher Kristian Barzikovski of the University of Grenoble Alps in France and his colleagues analysed KCL's involuntary recall in depth. The study found that KCL retrieves past memories far more effectively than ordinary people, while his mental capacity for future planning and other kinds of thinking remains normal. The researchers argue this is not a matter of generally superior memory, but rather a change in how the brain retrieves stored information.

The team ran a series of remote tests on KCL and confirmed that he has hyperthymesia, or HSAM. They estimate that only about 0.1 per cent of the global population possesses such extraordinary memory. People with this condition behave like anyone else; they learn everyday information just as well as ordinary people, but differ sharply in the way they recall their past.

Source: Science Alert