A Cortex case report says 16-year-old KCL met criteria for highly superior autobiographical memory: 13 of 15 sampled off-task thoughts (87%) were personal memories, versus about 39% in comparison data. The pattern was specific to personal memories, not general mind-wandering.
The report says KCL’s scores on specific autobiographical-recall measures were statistically expected to exceed those of 99.9% of the general population. His attention, working memory, executive function and general development appeared broadly typical. The remote assessment used established questionnaires and tasks after KCL contacted researcher Krystian Barzykowski in February 2025.
KCL reported detailed memories from approximately half the days since around August 2022, including recollections reaching back to roughly three months of age. His parents reportedly corroborated some memories from 2010 and 2011, but infant memories are difficult to verify independently. The case examines involuntary autobiographical memories, an area earlier HSAM research largely set aside; the researchers say broader conclusions require more participants and replication.
