Why are some quite mentally healthy people unable to remember events from their own past?
The memory of some people is arranged in such a way that they are able to remember in great detail almost every moment of their lives. This phenomenon was discovered several years ago and called hyperthymesia. And now researchers have discovered the reverse syndrome, which they call “autobiographical memory deficit.”
In their work, neuropsychologists describe three cases. AA is a 52-year-old married woman, BB is a 40-year-old single man, and CC is a 49-year-old cohabiting man. All three are doing fine with everyday life, they have a job, but at the same time they claim that all their lives they were not able to remember and relive their own past. In early adolescence, they first realized that they were suffering from a similar problem. At the same time, they normally remember facts and learn practical skills. Two of them had experienced depression in the past, but at the time of the study, it had already passed.
Read more:
- Charging for memory: how to stop forgetting everything
Three patients underwent rigorous neuropsychological testing for intelligence, memory, and mental productivity and scored at or above average. The only major exception was poor results on a test in which I had to draw a complex figure from memory. The researchers believe that the key to unraveling the mystery may lie precisely in the violation of visual memory.
Compared to other respondents (of approximately the same age and education), participants in the experiment were able to recall much less autobiographical details from adolescence and early adolescence. They remembered better in recent years, but scientists believe that this is due to compensation strategies – using diaries and photographs as clues, as well as due to the preserved ability to remember facts and details.
“How does your memory work?”
The BBC documentaries have collected in their film the most curious and significant medical and psychological experiments of recent years, explaining the properties of our memory.
Patients themselves described that they had little to no memories and were unable to re-experience past events. They also had difficulty imagining the future, consistent with the theory that memory and imagining the future use the same mental processes.
Brain scans showed no damage or disease, but when the patients tried to remember something from their past, key brain regions associated with autobiographical memory were less active than in the control group. Another difference recorded by scientists: the hippocampus of the right hemisphere, which plays an important role in memory, was slightly less than normal in patients. These changes may be related to memory deficits, but they are clearly different from those seen in so-called adolescent amnesia, in which memory regions of the brain are drastically reduced.
Scientists do not yet know whether such a syndrome is an extreme manifestation of the norm or still an obvious pathology, and are going to continue research.
Подробнее см. D. Palombo et al. «Severely deficient autobiographical memory (SDAM) in healthy adults: A new mnemonic syndrome», Neuropsychologia, April 2015.