Do People With Amnesia Know if Their Personality Has Changed?

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Amnesia. It's the favorite plot device of soap opera writers everywhere. Just when your favorite couple is finally about to get together, one of them has a car accident, and BAM! Amnesia. Now they can’t remember anything about their would-be lover, or even who they themselves are, throwing a wrench into the romance once again and making viewers wonder if those kids will ever be able to make it work. Scenarios like these have greatly influenced the average person's ideas about how amnesia works. The type of amnesia used in most movies and TV shows (even as there are inaccuracies in how it is portrayed) is called retrograde amnesia, or the inability to remember past information.

However, a more common form of amnesia is anterograde amnesia, in which damage to the brain leaves people no longer able to form new memories, but they still retain old memories, including previously acquired skills. One question a newly published study by Garland and colleagues asked was how the inability to store new information affected patients’ sense of their own personalities. Can people with this form of amnesia accurately understand themselves? Or does the amnesia distort their self-views?

A large body of research has confirmed that personality, or our relatively consistent thoughts, feelings, and behaviors across a variety of situations, changes over time. These changes occur in response to normal developmental processes, individual life events, and even efforts to change your own personality. Numerous studies have confirmed that while there is an element to personality that is pretty stable, to some extent our personalities continue to develop and change even into old age.

One question you might ask is how a person's personality can change when they are unable to store and reflect on their lives and relationships. Although some personality change comes from reacting to our own lives, some appear to be simply developmental; for example, most people, regardless of certain life events, tend to become more conscientious as they age. Thus, we might expect people with amnesia to experience these normal developmental changes as well. But another big question remains: If people with anterograde amnesia cannot form memories for new information, can they have an accurate view of their own developing personalities?

Amnesia of any kind is extremely rare, so the sample for this study consisted of seven patients from the Iowa Neurological Patient Registry who had been diagnosed with severe anterograde amnesia following damage to their medial temporal lobes and/or hippocampus. Patients’ injuries that caused the onset of amnesia had occurred between 4 and 28 years earlier, with the injury occurring between ages 28 and 52.

In order to determine whether amnesia allows people to maintain a sense of self, and whether that sense of self reflects participants' personality development or is stuck at a pre-injury state, researchers asked patients about their personalities over a period of time. After the initial assessment, they were again asked to provide information on their personalities one day later, after two weeks, after two months, and finally, one year later. Researchers also asked patients’ caregivers about the patients’ personalities, and similarly, they were asked again at 2 months and 1 year after the baseline assessment.

Both patients and their caregivers provided this information using the Big Five Inventory, a commonly used and well-validated personality questionnaire that measures the personality traits of extraversion, agreeableness, conscientiousness, emotional stability, and openness to experience, and has often been used to track personality development over time. In personality development research, researchers typically measure people’s personalities at various time points and calculate the degree of similarity of these ratings over time using statistical modeling and metrics like test-retest correlations. This allows us to see how much personality is changing, when, and in which specific traits.

Additionally, this can be used to determine the degree to which people's perceptions of their own personalities are in line with others' perceptions of them. In most studies of self-other agreement, we would expect both the self and others to have a degree of accuracy in reporting a person's personality. However, in the current study, researchers measured self-caregiver personality agreement to examine the extent to which patients' self-views were accurate and up to date (in other words, the caregiver was used as the benchmark for accuracy).

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Garland and colleagues wondered if deficits in declarative memory, a type of memory that pertains to life events and facts, would inhibit amnesia patients from being able to recognize their own personality development. They found that patients had a fairly stable view of their own personalities over the one-year span. This is not uncommon in personality research—in non-amnesic people, we might expect people to display some change, but over this period of time, there is also generally a lot of consistency in their personality.

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When caregivers were asked about the patients' personalities before they developed amnesia, their perceptions and the patients' aligned very closely, and they had a similar level of self-other agreement that we would see in typical samples. However, it appeared that over this year-long period, caregivers' reading of their patients' personalities and the patients' self-understandings deviated; self-other agreement was lower than researchers typically see in people without amnesia. In other words, caregivers noticed changes in patients' personalities that the patients themselves appeared unable to track.

The researchers concluded that anterograde amnesia does not prohibit people from maintaining a sense of their own personality, but that their idea of who they are may simply not be updateable. It may be difficult to think about how a person would undergo personality change if they cannot recall and reflect on their lives after a certain point. But this research points to the idea that perhaps it can nonetheless, and that loved ones and close others can see it.