The study, led by Dr. Shayna Rosenbaum, a cognitive neuropsychologist at Baycrest's Rotman Research Institute and assistant professor of psychology at York University, found that severe loss of autobiographical episodic memory does not necessarily compromise the ability to figure out the mental states of other people, including their feelings and intentions.
Understanding the feelings and intentions of others is the basis of a person's socialization and what makes us human. It's known as 'Theory of Mind' and associated with the prefrontal cortex.
In the study, the researchers examined two individuals who had limited autonoetic awareness, a rare cognitive condition. The individuals, known as K.C. and M.L., had sustained severe head injuries several years earlier in motorcycle and cycling accidents that erased most of their autobiographical episodic memory.
Both of them could no longer remember personal episodes of their past and how they felt. During the study, K.C., M.L. and 14 healthy controls were put through a series of tests widely known to be sensitive to 'Theory of Mind' and perspective taking i.e. the clear appreciation of empathy, deception, sarcasm and false beliefs in others.
Some of the tests involved looking at the eye regions of faces to determine if the person was deceitful or playful, and viewing emotional scenarios and listening to narratives to determine the other's mental state.
The analysis of the study found that K.C. and M.L. performed as well as healthy subjects on all measures even though they had severely impaired autonoetic awareness. 'We found that if you're trying to put yourself mentally in someone else's shoes, you don't need to put yourself in your own shoes first,' Rosenbaum said.
Rosenbaum suggested that the preserved ability to infer other people's feelings and intentions might be related to semantic memory, knowledge of general facts about the world and people that was left intact after the injury. She said that even though there might be some social consequences of losing your autobiographical memory, it doesn't mean all is lost.
'The person can still be in tune with others' feelings and intentions which can help sustain social relationships, especially with loved ones. It's encouraging to know that this ability may be more resilient and preserved in us than was first thought,' Rosenbaum said.
'Our findings suggest that episodic memory is not necessary to have normal insight into other people's minds,' said Dr. Endel Tulving, a cognitive psychologist. 'We still do not know whether episodic memory might be necessary for the development of such an insight in the first place! This is yet another open problem.' Tulving said.