family—together. It endures as a rich, nearly palpable memory within the minds of both Miller parents and each of their children, remote in time and space but instantly accessible to any Miller at the mere utterance of a simple prompt: Remember when Su ran out into the street at Niagara Falls?
Brain scientists call these “episodic memories”—recollections of specific events from one’s lived experience. Episodic memory is thought to be a distinctly human trait, one of the few things that set us apart from the other animals, and perhaps the most important quality that defines each of us as individuals.
But I have no memory of that episode at Niagara Falls. In fact, I have no lingering episodic memory, not a stitch, from the first twenty-two years of my life. My sense of who I am, and my relationship with the other Millers, is entirely based on the events of the last twenty years.
For most people, episodic memory is synonymous with memory itself. But it is only one of at least three different kinds of memory, along with “semantic memory” and “procedural memory.” Each has a different purpose, and each resides in different places within the human brain.
Procedural memory is the remembered ability to perform tasks. We never forget how to ride a bike (or to walk, or to talk, or to swing a bat) because of the fundamental strength of our procedural memories. Semantic memory is the recollection of facts: names, concepts, and even specific events, but not events we recall as scenes from our own life. Most people have semantic memories of Woodstock; those who attended have episodic memories as well. All of my memories from childhood are semantic memories;stories that have been told to me and stories that I can recite, but that don’t feel like any real experiences I have lived. Anyone who has studied psychology in school will also remember the concept of short-term and long-term memories. Short-term memories are disposable, lasting only seconds or minutes: Post-its from our brain. We use short-term memory to recall the digits of a telephone number to be dialed once, the location of a coconut we just spotted in a tree, and other facts useful for our immediate survival but trivial in the broader course of life. Long-term memory is reserved for information useful beyond the present moment: the directions to our house; the phone numbers of loved ones; our blood type; our first date with a spouse.
Repetition—learning—consolidates short-term memories into long-term ones. The consolidation process can be voluntary, as in studying for an exam, or involuntary, as in those conditioning experiments with animals that used electric shocks and treats to “teach” the rat to find the pellet. Long-term memories can endure for weeks or years or decades. The human brain is forever sifting through memories, preserving the ones that matter for our survival and discarding those that don’t. Memories are Darwinian: Only the ones the brain deems most vital to our survival will, themselves, survive.
That was news to me. Jim remembers a dog-walk conversation that we had less than ten years ago when he first realized how I thought my memory was supposed to work. For most of my life I thought that other adults remembered every fact, every image, every scene they had ever lived, recording memories like a twenty-four-hour security camera. But I guess it makes sense: Who could possibly handle that much memory?
Our brain’s anatomy plays a role in memory; the recall of amemory is thought to involve several areas of the brain. Different regions record sights and sounds, numbers and names, motor skills and three-dimensional spaces. To recall a whole memory, the medial temporal lobe, a section at the brain’s inner core, must fetch each individual component from different places in the brain. The medial temporal lobe is also thought to help us consolidate short-term episodic and semantic memories into long-term ones, although it does not
Brain scientists call these “episodic memories”—recollections of specific events from one’s lived experience. Episodic memory is thought to be a distinctly human trait, one of the few things that set us apart from the other animals, and perhaps the most important quality that defines each of us as individuals.
But I have no memory of that episode at Niagara Falls. In fact, I have no lingering episodic memory, not a stitch, from the first twenty-two years of my life. My sense of who I am, and my relationship with the other Millers, is entirely based on the events of the last twenty years.
For most people, episodic memory is synonymous with memory itself. But it is only one of at least three different kinds of memory, along with “semantic memory” and “procedural memory.” Each has a different purpose, and each resides in different places within the human brain.
Procedural memory is the remembered ability to perform tasks. We never forget how to ride a bike (or to walk, or to talk, or to swing a bat) because of the fundamental strength of our procedural memories. Semantic memory is the recollection of facts: names, concepts, and even specific events, but not events we recall as scenes from our own life. Most people have semantic memories of Woodstock; those who attended have episodic memories as well. All of my memories from childhood are semantic memories;stories that have been told to me and stories that I can recite, but that don’t feel like any real experiences I have lived. Anyone who has studied psychology in school will also remember the concept of short-term and long-term memories. Short-term memories are disposable, lasting only seconds or minutes: Post-its from our brain. We use short-term memory to recall the digits of a telephone number to be dialed once, the location of a coconut we just spotted in a tree, and other facts useful for our immediate survival but trivial in the broader course of life. Long-term memory is reserved for information useful beyond the present moment: the directions to our house; the phone numbers of loved ones; our blood type; our first date with a spouse.
Repetition—learning—consolidates short-term memories into long-term ones. The consolidation process can be voluntary, as in studying for an exam, or involuntary, as in those conditioning experiments with animals that used electric shocks and treats to “teach” the rat to find the pellet. Long-term memories can endure for weeks or years or decades. The human brain is forever sifting through memories, preserving the ones that matter for our survival and discarding those that don’t. Memories are Darwinian: Only the ones the brain deems most vital to our survival will, themselves, survive.
That was news to me. Jim remembers a dog-walk conversation that we had less than ten years ago when he first realized how I thought my memory was supposed to work. For most of my life I thought that other adults remembered every fact, every image, every scene they had ever lived, recording memories like a twenty-four-hour security camera. But I guess it makes sense: Who could possibly handle that much memory?
Our brain’s anatomy plays a role in memory; the recall of amemory is thought to involve several areas of the brain. Different regions record sights and sounds, numbers and names, motor skills and three-dimensional spaces. To recall a whole memory, the medial temporal lobe, a section at the brain’s inner core, must fetch each individual component from different places in the brain. The medial temporal lobe is also thought to help us consolidate short-term episodic and semantic memories into long-term ones, although it does not
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