Propranolol, an inexpensive and widely available beta blocker, is known to be effective in preventing post traumatic stress disorder (PTSD) if administered soon after a traumatic experience. In a recent article, Elsey and Kindt (2016) describe a new way of using propranolol to diminish PTSD symptoms in individuals who already have the condition. The authors describe research that indicates that propranolol can be effective in treating PTSD when administered during the reconsolidation of long-term memories. Taking propranolol as the memory is retrieved diminishes the emotional bite of traumatic memories without erasing them, and without significantly affecting declarative memory for the event.
When memory is characterized as foundational to narrative identity, memory modification has been seen as having morally perilous consequences because of its potential to change or even disrupt identity. But there is reason to doubt that memory modification can have this effect. In a series of studies, Loftus (2003) has shown that memory is reconstructed at the time of recall, and that it is vulnerable to retroactive interference. A memory can be altered in a number of different ways: it can be influenced by how we are questioned about the witnessed event; it can be contaminated by false information presented after the happening; and it can be changed through conversation about what was observed. Additionally, even autobiographical memories can be unreliable. Sheen et al. (2001, 2006) showed that siblings who concur on the details of childhood memories will disagree about their ownership. If the memory was about achievement, the siblings were more likely to remember it as happening to them, and if it was about wrongdoing they were more likely to attribute it to their brother or sister. This illustrates a further point, which is that instead of memory grounding our sense of self, it is actually the other way around--we have a narrative about who we are and we use it to reshape our past (Wilson and Ross 2003).
Despite this evidence for the unreliability of witnessed and autobiographical memory, one could still maintain that an individual might require certain core memories to maintain a sense of continuity of their identity over time. However, a case of memory loss presented by Klein and Nichols (2012) indicates otherwise. This is a case of a man who suffered significant head trauma in a motorcycle accident and experienced retrograde and anterograde amnesia for events that occurred soon before and after his accident. This individual had an intact episodic memory for earlier events from his past, but he described remembering those events as if they had happened to somebody else. Nonetheless, he reported a continuity of his sense of self. Although the specifics of this case are unusual, they suggest that narrative identity does not depend on the maintenance even of core memories.
In their article, Elsey and Kindt (2016) are careful to argue only for the permissibility of the use of propranolol to treat diagnosed medical or psychiatric conditions. But if it is recognized that such memory modification may not be a challenge to narrative identity, there is room for a stronger conclusion. If effective and safe methods are available, memory modification is morally permissible even beyond the treatment of disease, but more broadly when used toward improvement in quality of life.