When I am explaining the neurobiology of grief, I usually start with a metaphor that is based on a familiar experience. However, for the metaphor to make sense, you have to accept a premise. The premise is that someone has stolen your dining room table.
Imagine waking up thirsty in the middle of the night. You get out of bed and head to the kitchen to get a glass of water. Down the hall, you cross the dark dining room toward the kitchen. At the moment that your hip should bump into the hard corner of the dining room table, you feel . . . hmm, what is it you feel? Nothing. You are suddenly aware that you don’t feel anything in that spot at the height of your hip. That is what you are aware of—not feeling something, something specific. The absence of something is what has drawn your attention. Which is weird—we usually think of something as drawing our attention—how can nothing draw our attention?
Well, in fact, you are not actually walking in this world. Or, more accurately, you are walking in two worlds most of the time. One world is a virtual reality map made up entirely in your head. Your brain is moving your human form through the virtual map it has created, which is why you can move through your house fairly easily in the dark; you are not using the external world to navigate. You are using your brain map to get around this familiar space, with your human body arriving where your brain has sent it.
You can think of this virtual brain map of the world as the Google map in your head. Have you ever had the experience of following voice directions, without fully paying attention to where you are driving? At some point, the voice tells you to turn onto a street, but you may discover that the street is actually a bike path. GPS and the world do not always match up. Like Google maps, your brain map relies on prior information it knows about the area. To keep you safe, however, the brain has entire areas devoted to error detection—perceiving any situations where the brain map and the real world do not match. It switches to incoming visual information when an error is detected (and, if it is nighttime, we may decide to flip on the lights). We rely on our brain maps because walking your body through your mental map of the world takes a lot less computing power than walking through your familiar house as though it were your first experience—as though you were discovering each time where the doorways and walls and furniture are, and deciding how to navigate each one.
No one expects their dining room table to get stolen. And no one expects their loved one to die. Even when a person has been ill for a very long time, no one knows what it will be like to walk through the world without this other person. My contribution as a scientist has been to study grief from the brain’s perspective, from the perspective that the brain is trying to solve a problem when faced with the absence of the most important person in our life. Grief is a heart-wrenchingly painful problem for the brain to solve, and grieving necessitates learning to live in the world with the absence of someone you love deeply, who is ingrained in your understanding of the world. This means that for the brain, your loved one is simultaneously gone and also everlasting, and you are walking through two worlds at the same time. You are navigating your life despite the fact that they have been stolen from you, a premise that makes no sense, and that is both confusing and upsetting.
For the brain, your loved one is simultaneously gone and also everlasting, and you are walking through two worlds at the same time.
In addition to carrying around wide-ranging virtual maps, another of the marvels of the brain is that it is a remarkably good prediction machine. Much of the cortex is configured to take in information and compare that information to what has happened before, to what it has learned through experience to expect. And because the brain excels at prediction, it often just fills in information that is not actually there—it completes the patterns it expects to see.
When you walked through the space formerly occupied by the dining room table, your brain actually felt the table. Then it noticed the difference between the pattern of sensation that it expected and logged, and what actually happened. Imagine the man whose wife has returned home from work at six o’clock every day for years. After her death, when he hears a sound at six o’clock, his brain simply fills in the garage door opening. For that moment, his brain believed his wife was arriving home. And then the truth would bring a fresh wave of grief.
It requires additional time for you to consult with other parts of your brain that report your wife is no longer alive and could not possibly be opening the garage door. Sometimes all this occurs so quickly that it is below the threshold of consciousness, and all we know is that we are suddenly overwhelmed with tears. Therefore, perhaps it is not so surprising that we “see” and “feel” our loved ones after they have died, especially soon after the death. Our brain is filling them in by completing the incoming information from all around us, since they are the next association in a reliable chain of events. Seeing and feeling them is quite common, and it definitely isn’t evidence that something is wrong with us.
When we experience a loss through death, our brain initially cannot comprehend that the dimensions we usually use to locate our loved ones simply do not exist anymore.
Additionally, our predictions change slowly, because the brain knows better than to update its whole prediction plan based on a single event. Or even two events, or a dozen events. The brain computes the probabilities that something will happen. You have seen your loved one next to you in bed when you wake up every morning for days and weeks, months, and years. This is reliable lived experience. Abstract knowledge, like the knowledge that everyone will die someday, is not treated in the same way as lived experience. Our brain trusts and makes predictions based on our lived experience. When you wake up one morning and your loved one is not in the bed next to you, the idea that she has died is simply not true in terms of probability. For our brain, this is not true on day one, or day two, or for many days after her death. We need enough new lived experiences for our brain to develop new predictions, and that takes time.
The brain learns whether we intend to learn or not. It does not wait patiently until we say, “Hey, Siri,” and then begin encoding whatever happens next. Our brain continuously logs the information received through all of our senses, building up a vast store of probabilities and likelihoods, noting associations and parallels between events. Often this happens without our conscious awareness of those sensations, or of the associations made. This unintentional learning has pros and cons. Because learning is unrelated to our intentions, the brain is learning the real contingencies of the world, even when we are ignoring them or do not consciously notice them. Your brain continues to note the fact that your loved one is no longer present day after day and uses that information to update its predictions about whether they will be there tomorrow. That is why we say that time heals. But actually, it has less to do with time and more to do with experience. If you were in a coma for a month, you would not learn anything about how to function without your husband after you came out of the coma. But if you go about your daily life for a month, even without doing anything someone would recognize as “grieving,” you will have learned a great many things. You will learn that he didn’t come to breakfast thirty-one times. When you had a funny story to share, you called your best friend and not your husband. When you washed the laundry, you didn’t put any socks in his drawer.
If you go about your daily life for a month … you will have learned a great many things. You will learn that he didn’t come to breakfast thirty-one times. When you had a funny story to share, you called your best friend and not your husband.
When we experience a loss through death, our brain initially cannot comprehend that the dimensions we usually use to locate our loved ones simply do not exist anymore. We may even search for them, feeling like we might be a bit crazy for doing so. If we feel that we know where they are, even in an abstract place like Heaven, we may feel comforted that our virtual map just needs to be updated to include a place and time that we have never been. Updating also includes changing our prediction algorithm, learning the painful lessons of not filling in the gaps with the sights, sounds, and sensations of our loved ones.
Keep in mind that the brain cannot learn everything at once. You cannot go from arithmetic to calculus without many, many days of practicing multiplication tables and solving differential equations. In the same way, you cannot force yourself to learn overnight that your loved one is gone. However, you can allow your brain to have experiences, day after day, which will help to update that little gray computer. Taking in everything around us, which updates our virtual map and what our brain thinks will happen next, is a good start for being resilient in the face of great loss.
Adapted from The Grieving Brain: The Surprising Science of How We Learn from Love and Loss by Mary-Frances O’Connor and reprinted with permission from HarperOne, an imprint of HarperCollins Publishers. Copyright © 2022 by O’Connor Productions, Inc.