In an attempt to begin to tackle the age-old question of what shapes one's identity, researchers at Duke and the University of Arizona surveyed the caregivers of those with different neurodegenerative diseases to see which ones seemed most likely to strip away the essence of a person. Reporting in the journal Psychological Science, they say that people can be stripped of their abilities to move, think, and even remember, but it is not until they are stripped of their moral characteristics—i.e., courage, kindness, and honesty—that their caregivers begin to feel that the person's true identity is slipping away. "Essentially, identity is not what we know, but what we stand for," reports Scientific American.
To test this, the researchers asked the caregivers of 248 people suffering from either Alzheimer's, fronto-temporal dementia (FTD), or amyotrophic lateral sclerosis (ALS) such questions as, "How much do you sense that the patient is still the same person underneath?" Those caring for ALS patients were least likely to feel an essential metamorphosis in identity has occurred, while those caring for FTD patients, who suffer from frontal control damage that impacts things like empathy and impulse, were the most likely to feel the patient's identity had changed, reports the Wall Street Journal, which calls the research "profound. Our moral character, after all, is what links us to other people." A statistical analysis of all three groups found changes in moral behavior to predict changes in perceived identity more than changes in memory or intellect, regardless of the type of disease. (A 38-year-old with Alzheimer's says, "I don't feel like myself because of this disease.")