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The Brain’s Self
The year is 2029. Technology in Japan has advanced to the point that many humans have cybernetic bodies and computerized brains. In this cyberpunk society, an individual’s self and mind is known as a ghost, and their body is the shell within which it is contained. This, though, makes some individuals question their identity, even if they are not completely computerized. If you recognize this as the plot of “Ghost in the Shell”, you’d be right.
“Ghost in the Shell” is an anime movie set in a society in which technology has advanced to the point where cyborgs are common, with cybernetic bodies and computerized brains. The protagonist, Major Motoko Kusanagi, is a female cyborg who has various technological improvements that enhance her abilities of surveillance, communication, and combat. However, with all of these enhancements comes the question of identity, and thus the film incorporates philosophical themes that focus on self-identity in a technologically advanced world. Throughout the movie, Kusanagi questions identity, including her own:
“There are countless ingredients that make up the human body and mind, like all the components that make up me as an individual with my own personality. Sure I have a voice and face to distinguish myself from others. But my thoughts and memories are unique only to me.”
Major Motoko Kusangi
With the phrase, “my thoughts and memories are unique only to me”, Kusanagi makes the point that: since I have thoughts unique to me, I am me. What Kusanagi says in this quote introduces an important theme: what is the self? To Rene Descartes, a 17th century philosopher, since we are thinking, we can know that we exist. To him, our sense of self is assured because we are able to think about ourselves. We can be deluded and gaslit by others into doubting whether anything exists, but because we are able to doubt OUR existence, we can know that, at the very least, our mind exists. As he famously put it: ”I think, therefore I am.”
Mind-Body Dualism
“Cogito ergo sum”, or, “I think therefore I am” in English, is the Latin phrase coined by Descartes, who made a tremendous contribution to our understanding of our minds. By this phrase, Descartes suggests that since we OURSELVES are able to have thoughts, we can know that we OURSELVES exist; it is a matter of existence, but more importantly, it is a matter of the self. We can be certain of our own identity because we can doubt it.
Descartes is most famous for his contributions to what is known as mind-body dualism: the belief that there are two substances within ourselves, that are completely distinct but are causally linked. The nonphysical mind is the substance responsible for our thoughts, beliefs, and emotions (a thinking substance); the physical body (brain) is the matter that is controlled by and communicates with the mind (an extended substance, as he puts it). The mind is what senses, feels, and does things, not the body.
The problem with this, however, is that it raises the question of how we are able to relate the properties of the mind (thinking, sensing, believing, etc.) with the properties of the physical body (matter, atoms, neurons, brains), known as the mind-body problem (https://spot.colorado.edu/~heathwoo/Phil100/mindintro.html). This was a big question in philosophical debate in Descartes’s time and, despite the major advancements in neuroscience, still remains so.
Recently, there has been a lot of research into how the concept of self appears in the brain, and there are interesting findings that suggest the self is recognized by a specific region of the brain in the frontal lobe. Moreover, because Descartes described the self as resting within the nonphysical mind (or thinking substance), evidence that this region of our brain is responsible for recognizing the traits of our self would seem to reject Descartes’s hypothesis, as it is obviously part of the body (or extended substance)-
Therefore, I will take it a step further and ask: what is the self to the brain?
Who Am I?
The frontal lobe of the brain is, as it sounds, the foremost region of our brain. It is the most recent addition to the brain in our evolutionary history, and its size is what distinguishes us from the rest of the animal kingdom. Humans and monkeys, for example, have this brain region, whereas lizards don’t.
The frontal lobe is what does a lot of our high-order thinking. To Descartes, it would be the mind (our thinking substance), essentially. The frontal lobe is also divided into several anatomical sections, based on their different functions. The very front of the brain, the prefrontal cortex (PFC), is a region that is even more specialized for our thoughts and perception of ourselves.
There is one region of the PFC that has recently shown promise in our understanding of ourselves. It thinks about and recognizes the traits that describe who we are–it thinks, therefore it is; this section is known as the medial PFC (mPFC).
A key phenomenon we need to understand to interpret this research is known as the self-reference effect (SRE): information related to ourselves is remembered more easily than information related to others (https://academic.oup.com/scan/article/16/12/1205/6292181?login=false). SRE has been strongly linked to the mPFC when asking individuals about their present self; however, results from a neuroimaging technique that measures the activity in the brain showed that there was diminished activity in the mPFC when asked about their future self, which was nearly the same as the activity shown with information related to other people. Hence, to further explore this, researchers from Italy designed an experiment to test how SRE presents itself in the brain in both the present AND the future.
Who will I be?
Another region of the PFC, the ventromedial PFC (vmPFC), also recognizes traits that refer to ourselves (https://www.scientificamerican.com/article/how-our-brain-preserves-our-sense-of-self/). However, as exemplified by researchers, the vmPFC seems to have that property that the mPFC lacked: a strong SRE was still present when patients with an intact vmPFC imagined what they might be like in the future (https://academic.oup.com/scan/article/16/12/1205/6292181?login=false).
In the experiment, researchers presented participants with a series of trait adjectives and asked them whether the adjectives described their present self, future self, another person (presently), or another person in the future. They were then later asked to recall the adjectives corresponding to each group they had heard. Predictably, because of SRE, participants recalled traits describing themselves much more than those describing others. As well, other results show that this region performs a different role in our identity in each hemisphere: in our left hemisphere, activity in the vmPFC correlated with the participant’s ability to judge whether the trait applies to their identity or not (certainty); the right hemisphere’s vmPFC showed activity related to their ability to judge how important that trait is to their identity (importance) (https://academic.oup.com/cercor/article/22/3/659/327966?login=false). For instance, if the left hemisphere were to recognize “intellectual” as referring to the participant when presented with a list of trait adjectives, the right hemisphere would judge the importance of that trait to the participant.
The study compared three groups of participants: neurologically healthy individuals, patients who had brain damage but not to the area of interest (vmPFC), and patients that had damage specifically to the vmPFC. By studying both patients whose vmPFCs were injured and control patients with brain injury that did not affect the vmPFC, the researchers were able to show that SRE deficiency was not simply a consequence of brain injury in general.
Those with damage to their vmPFC exhibited little to no evidence of SRE, meaning that they were unable to identify traits that described themselves or were uncertain about them. Furthermore, this lack was identified both when individuals were asked about their present self and future self. In healthy and control patients, however, SRE was correlated with activity in the vmPFC, with both information about the self from the present and future. The vmPFC did show diminished activity with regard to information regarding the future self, but this difference was proportional across all three groups.
These findings regarding the vmPFC uncover something unique from the previous findings of the mPFC, where there was an absence of response in the future self condition. Since control brain injury patients had SRE results proportional to healthy controls, the absence of SRE shown by vmPFC patients is even more illustrative. Therefore, we can conclude that this region, the vmPFC, is a major contributor to our self-identity. It is the ghost of our brain in the shell of our body.
It Thinks, Therefore I Am
We return now to the question we asked at the beginning: what is the self to the brain? After reflecting on the components that make up who she is and distinguish her from others (“my thoughts and memories are unique only to me”), Kusanagi continues saying how all of these things make up who she is:
“Each of those things are just a small part of it [referring to her technological enhancements, thoughts and memories]. I collect information to use in my own way. All of that blends to create a mixture that forms me and gives rise to my conscience.”
Major Motoko Kusangi
What Kusanagi alludes to here is that, yes, she has all of these things that are “unique only to [her]”, but what truly makes us ourselves is what we make of this information. Our brains blend together all of the information we gather, and from that information, we assign to ourselves traits that we believe describe us and describe who we will be. We remember these traits more readily because of SRE, and the processes underlying SRE would not be possible without our vmPFC, as clearly demonstrated by the study which showed those with lesions to their vmPFCs to have a virtually absent SRE. Who would we be without our brains? Who would we be without our vmPFCs?
References
- Oshii, Mamoru. (Director). (1995). Ghost in the Shell [Film]. Production I.G.
- https://spot.colorado.edu/~heathwoo/Phil100/mindintro.html
- https://academic.oup.com/scan/article/16/12/1205/6292181?login=false
- https://www.scientificamerican.com/article/how-our-brain-preserves-our-sense-of-self/
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