My problem with people who elevate the human "self" into something grandiose -- like an eternal soul -- is that they muddy the waters regarding what the self truly is.
An article in the August 2022 issue of Scientific American, "Creating Our Sense of Self," goes a long way toward clearing things up.
Download How Our Brain Preserves Our Sense of Self - Scientific American
The first paragraphs lay out the basics of the self.
We are all time travelers. Every day we experience new things as we travel forward through time. As we do, the countless connections between the nerve cells in our brain recalibrate to accommodate these experiences. It's as if we reassemble ourselves daily, maintaining a mental construct of ourselves in physical time, and the glue that holds together our core identity is memory.
Our travels are not limited to physical time. We also experience mental time travel. We visit the past through our memories and then journey into the future by imagining what tomorrow or next year might bring. When we do so, we think of ourselves as we are now, remember who we once were and imagine how we will be.
Some religiously-minded people glibly talk about doing away with the self as if this was an unalloyed good thing. But as the excerpt above says, the self is our sense of a core identity. It requires memory and imagination to function as it should.
There's evidence that a particular region of the brain is responsible for this.
A study, published in the journal Social Cognitive and Affective Neuroscience (SCAN), explores how one particular brain region helps to knit together memories of the present and future self. When people sustain an injury to that area, it leads to an impaired sense of identity. The region—called the ventral medial prefrontal cortex (vmPFC)—may produce a fundamental model of oneself and place it in mental time. When the region does so, this study suggests, it may be the source of our sense of self.
So how did the researchers determine the extent to which someone has a sense of self? This is necessary in science, but not in religion or mysticism, because science seeks what is real and true, not what is fantasized and false.
Psychologists have long noticed that a person's mind handles information about oneself differently from other details. Memories that reference the self are easier to recall than other forms of memory.
They benefit from what researchers have called a self-reference effect (SRE), in which information related to oneself is privileged and more salient in our thoughts. Self-related memories are distinct from both episodic memory, the category of recollections that pertains to specific events and experiences, and semantic memory, which connects to more general knowledge, such as the color of grass and the characteristics of the seasons.
SREs, then, are a way to investigate how our sense of self emerges from the workings of the brain—something that multiple research groups have studied intensely. For example, previous research employed functional magnetic resonance imaging (fMRI), a method that uses blood flow and oxygen consumption in specific brain areas as a measure of neural activity, to identify regions that were activated by self-reference. These studies identified the medial prefrontal cortex (mPFC) as a brain region related to self-thought.
This area, the mPFC, can be further divided into upper and lower regions (called dorsal and ventral, respectively), and it turns out that each one makes different contributions to self-related thought. The dorsal section plays a role in distinguishing self from other and appears to be task-related, whereas the ventral section, the vmPFC, contributes more to emotional processing.
The researchers studied three groups of people. One group consisted of seven people who had lesions in the vmPFC part of the brain mentioned above. Another group consisted of eight people with injuries to other parts of the brain. The third group consisted of 23 healthy people.
All people in the study underwent a thorough neuropsychological evaluation, which confirmed that they were within normal ranges for a variety of cognitive assessments, including measures of verbal fluency and spatial short-term memory. The researchers then asked the participants to list adjectives to describe themselves and a well-known celebrity, both in the present and 10 years in the future. Later, the participants had to recall these same traits.
These were the findings.
The researchers discovered that people in their control group could recall more adjectives linked to themselves in the present and future than adjectives linked to the celebrity. In other words, scientists found that the self-reference effect extends to both the future and the present self. Although there was some variation in the group—people with brain injuries to areas other than the vmPFC were somewhat less able to recall details about their future self when compared with healthy participants—the self-reference effect still held true.
Results were distinctly different, however, for the participants with injuries to the vmPFC. People with lesions in this area had little or no ability to recall references to the self, regardless of the context of time. Their identification of adjectives for celebrities in the present or future was also significantly impaired when compared with the rest of the participants' responses.
In addition, people with vmPFC lesions had less confidence about an individual's ability to possess traits than other people in the study. All of this evidence points to a central role for the vmPFC in the formation and maintenance of identity.
The last part of the article had a couple of observations that fascinated me. One is that other studies had shown that when we think of our past self, that former version of ourselves seems like a stranger to us.
More broadly, the study helps us understand how self- related memories—recollections key to maintaining our core sense of identity—depend on the function of the vmPFC. But what about our past selves? Curiously, in previous studies that asked people to consider their past selves, there was no more activation of the mPFC than when considering someone else. Our past selves seem foreign to us, as if they were individuals apart from us.
One idea that scientists have put forward to understand this distinction is that perhaps we are not very kind in our judgments of our past selves. Instead we may be rather critical and harshly judgmental of our previous behavior, emotions and personal traits. In these situations, we may use our past primarily to construct a more positive self-image in the present. Put another way, because we may recognize flaws in our past self's behavior, we tend to distance ourselves from the person we once were.
I also resonated with the notion that memory is a form of imagination. It's well known that every time we retrieve a memory, there's a strong likelihood that this changes the memory. So over time our memories may become less and less accurate as regards what actually happened, since we embellish the memory -- often to make the past more acceptable or satisfying to our present self.
Bringing the present and future into the spotlight, then, is central to understanding the way our brain and thoughts build our current identities. In many ways, it makes sense that the mPFC is important in this process of recalling present details and imagining future ones that build on our recollections. The prefrontal cortex, including the mPFC and its subdivisions, forms a network in the brain that is involved in future planning.
That network also includes the hippocampus, a brain structure that is central to episodic memory formation and that can track moments as sequential events in time. In past work, researchers have found that manipulating the activity of the hippocampus alters creative and future imaginings, which suggests an important role for brain structures supporting memory in imagining the future.
In fact, although we often think of memory as the brain's accurate and dispassionate recording device, some scholars have characterized it as a form of imagination.