Australasian Science: Australia's authority on science since 1938

Life in the Third Person

By Tim Hannan

People with severely deficient autobiographical memory do not re-experience their past.

Implausible forms of amnesia are popular fodder for Hollywood, with movies such as Dead Again, The Long Kiss Goodnight and the Jason Bourne series all featuring characters who, despite possessing a full understanding of the workings of the world, display an almost complete inability to recall any personal information. Such a condition has never been documented by clinicians, and the notion of a selective, total amnesia for autobiographical amnesia has generally been assumed to be impossible.

However, a recent study has reported what appears to be a milder form of the fictional amnesia in several individuals with a specific inability to relive personal experiences despite retaining otherwise average memory and general knowledge of the world. In this condition, termed “severely deficient autobiographical memory”, recollections are based solely on factual, non-personal knowledge, or as one author put it, the individual is obliged to “live life in the third person”.

The main features of human memory functioning were identified in the 1980s, with the delineation of several memory systems mediated by diverse regions of the brain.

  • The implicit memory system enables the acquisition and performance of motor skills such as riding a bicycle, and is associated with the basal ganglia, motor cortex and cerebellum.
  • Semantic memory is one’s store of general, factual knowledge about the world, and is mediated by the temporal lobe and its connections to the frontal lobe.
  • The third component is autobiographical or episodic memory, which is the system that enables the recall of events from our personal experience.

The distinction between semantic and episodic memory pertains to the difference between the retrieval of a fact and the full recollection or re-experiencing of a moment. Knowing that Princess Diana died in a car crash in Paris is a function of semantic memory, while recalling your experience of hearing the news of this accident relies on your episodic memory, which is especially associated with the hippocampus and ventral regions of the frontal lobe.

When people acquire amnesia through an illness or injury, they lose the ability to store new facts, or to effectively retrieve knowledge. In one famous case from 1957, patient HM underwent temporal lobe surgery for intractable epilepsy, and suffered the near-complete loss of the ability to acquire new memories yet retained the ability to recall pre-surgical personal experiences, factual knowledge and implicit memory.

However, to date it has been less clear that people could have deficient episodic memory while possessing the normal ability to learn, retain and retrieve semantic knowledge.

In the study reported in the Neuropsychologia, Dr Brian Levine and colleagues described the detailed neuropsychological assessment of three individuals with striking difficulties recalling personal experiences (tinyurl.com/on4evt4). Each was a healthy, well-functioning adult in steady employment, with a normal level of intelligence and no history of brain injuries, seizures, stroke, neurological disease or psychological diagnoses. Yet while all three demonstrated the ability to report facts about their world, descriptions of their memories of past events were almost completely without any first-person perspective or sense of reliving the experience. Compared with others of the same age and educational background, the participants provided markedly fewer autobiographical details from their earlier years.

Neuroimaging of the brain found reduced activation in regions associated with autobiographical memory and visual memory. The hippocampus on the right side was also slighter smaller than in controls. These findings of right-hemisphere anomalies are particularly interesting as all three participants exhibited difficulty when asked to copy a complex geometric figure from memory. The authors speculate that there may be a link between visual memory, mediated by the right hippocampus, and the ability to create autobiographical memories.

Future research with individuals with severely deficient autobiographical memory is likely to clarify whether the condition arises from a discrete pathology, or reflects the end of a continuum ranging up to highly superior autobiographical memory. It will also be interesting to understand the impact of deficient autobiographical memory on one’s social experiences, daily function and quality of life, and to explore the possible relationship between autobiographical memory and emotional disorders such as post-traumatic stress disorder.

A/Prof Tim Hannan is Head of the School of Psychology at Charles Sturt University, and the Past President of the Australian Psychological Society.