Here’s a comment that most of us would attribute to an older adult: “I can’t remember what I did yesterday, but I can remember the name of my 4th grade teacher.” We seniors are known for being better at retaining long-term memories than at forming new memories. Are our long-term memories really that good, though? How does our ability to retrieve memories of years gone by compare with that of younger adults?
Researchers indicate that long-term memories for life events can be divided into two types and that older adults retain one type better than the other. First, there are memories related to a specific event (usually defined as something occurring within a 24-hour period). Such memories tend to include specific recollections about what was seen or felt that have the quality of actually re-experiencing the event. Second, there are memories about events that took place over an extended period of time or that happened on a number of occasions. These memories don’t have as much sensory or emotional specificity—thinking about them doesn’t have the same quality of mental time-travel that the first type of memories does. An example of the first, high-resolution sort of memory is my recollection of my visit about 11 years ago to my son’s house a couple days after the birth of my oldest grandson. I have a very clear, detailed memory of my grandson lying on the changing table, looking up at me, his limbs slowly rotating as we made eye contact. I remember the feeling of awe and of boundlessness I had at the time. An example of the second, low-resolution sort of memory is my recall of the dozen or so visits to my son’s house over the subsequent few years. I can remember some details, but they aren’t nearly as clear as that initial memory, and the visits run together in my mind.
Compared to younger adults, older adults can’t recall as many high-resolution memories, i.e. detailed memories of specific events. Instead, their recollections tend to be populated with broad, low-resolution memories—indistinct memories for events that were repeated more than once or occurred over an extended period of time. When older adults do have memories of events occurring on a single day, these often lack perceptual or emotional specificity. Older adults know what happened during such an episode, but usually can’t revisit the moment in a way that brings it back to life.
I’ve been engaging in more life review over the last year or so, which means I’m thinking more about the past. I get frustrated at times trying to call to mind specific memories. So many of my memories are not of discrete events but instead meld numerous instances of the same sort of event–driving a particular route, eating in a particular restaurant, conversing with a particular person–into a single memory. And so many memories have been striped of visual elements. I remember taking three semesters of calculus in college, for example, but can’t remember the classroom, the teacher, my fellow students, or any of the class sessions. As I write this, I’m trying to remember as many college professors as I can. I had more than 30 teachers, but can get a mental picture of only nine of them, and know the names of only six of those. From the research I described above, it seems that my experience is typical. Most of us over 60 have vague, general memories more often than we have detailed, specific ones. Our minds shuffle the deck of memories better than they deal out specific hands.
Except there is one portion of our lives for which we tend to retain more specific, detailed memories. A team of French researchers led by Pascal Piolino of the Universite Rene Descartes found that memories for specific events occurring in the first 17 years of life were particularly well-preserved among older adults. Maybe that’s why most of us are more nostalgic for the days of childhood and adolescence than for the days of our 20s or 30s. We prefer events to which we can mentally return over events we may remember but can’t revisit.
Note: I drew on several studies to compile the above findings. A recent study that refers to all the earlier studies I read is this one. The study by Piolino and colleagues described in the last paragraph is described more fully here.