rough translation:to be a true tsundere you need blonde hair and twintails
I won't be talking about what tsunderes are, you should know it by now if you're even remotely interested in the Japanese fictional media. Now, the character type itself was studied thoroughly times and times again, but the topic of my personal study lies in an uncharted territory.
To preface, there are two types of tsunderes, at least I would like to believe there are two main types.
The first type are characters who initially are hostile towards the love interest, but over time they slowly became attached to them and become affectionate. They may still show-off some signs of "tsun" later in the story, but it's done in a teasing manner, essentially it's something they overcome within their character arc. Then there's the second type, these characters also start with hostility, but… they don't stop. Even after they have acquired mutual understanding with their love interest, their "tsun" side is still going rampant. Whenever the love interest is in their head space, tsunderes of this type immediately start being aggressive, which manifests itself in verbal abuse, harassment and sometimes open violence.
As you could've guessed, I'm going to be talking about the second type. I won't be going into details as to why their personality is like that, it's always some childhood trauma or mental illness, and it's different from character to character. More specifically, I will be delving into this topic with a preconception that tsundere characters are mentally ill. That's right, something in their brain is not operating properly and I will be examining what exactly.
There's a reactive side of your brain — mainly amygdala, hypothalamus and periaqueductal gray. These parts decide how you react to any outside influence, be it a threatening object or an adorable one. It is also related to the neural reward system, but I don't know what to make out of it yet. Evidently, tsunderes (of the second type) have issues with these areas of their brain, it's clearly abnormal to be causing pain (emotional or even physical) to someone you deeply care about. It's not just irrational, it doesn't align with how humans are biologically. All of this is very similar to a phenomenon called "cute aggression".
Cute aggression is an aggressive behaviour found in humans, it happens when they see something cute, such as a young animal or a baby. Namely, people then greet their teeth, think about how they want to destroy this thing, clench their fists, etc. This phenomenon really strikes me as familiar… You see a similar response in tsundere characters. There are multiple studies that try to answer how exactly does it happen, and among other things they examine the cute aggression phenomenon.
What happens is that people usually don't go from happiness (caused by cute stimuli) to aggression right away, most of the time they feel an "overload" of happiness from seeing cute things and then the brain picks up an appropriate response, that being a "threat". Why? Because the brain thinks that if something is causing an overload, that clearly must be a threat to your well-being. In tsundere characters this response happens to be an aggressive, violent behaviour, often exaggerated, but clearly a sign of a mental disorder.
tl;dr
In summary, my hypothesis is that a strong emotion of love causes the tsundere's brain to "overheat" in the sense that it becomes overloaded with emotions beyond measure, causing the brain to consider the object of love as a "threat" and then choose to respond with aggression, specifically aggression because they have a strong issue with the following parts of their brain — the amygdala, hypothalamus or periaqueductal gray matter.
Sources:
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3260787/
- https://escholarship.org/uc/item/1h093538
- https://clarkrelationshiplab.yale.edu/sites/default/files/files/Psychological%20Science-2015-Arag%C3%B3n-259-73.pdf
- https://www.researchgate.net/profile/Yoshimi-Ohgami-2/publication/281311204_Source_Analysis_of_Stimulus-Preceding_Negativity_Constrained_by_Functional_Magnetic_Resonance_Imaging/links/63aa7ab503aad5368e43cbb2/Source-Analysis-of-Stimulus-Preceding-Negativity-Constrained-by-Functional-Magnetic-Resonance-Imaging.pdf
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