The Synergy of Hearing and Taste

Xiang Kun's apartment is only seventy square meters, consisting of two bedrooms and a living room. The balcony is also quite small, one might even say cramped.

However, a redeeming quality is the decent view; it is far enough from other high-rises that he can see the mountains in the distance.

Xiang Kun did not bring a chair out, choosing instead to lie directly on the balcony tiles—though, naturally, he had wiped the floor clean beforehand.

Under the cover of night, Xiang Kun's state is exceptional. His physical functions have reached a peak, and his sensory abilities, following targeted training after his last three blood-drinking sessions and subsequent mutation, have improved significantly.

However, limited by his equipment and resources, he has no way to conduct accurate tests or statistics. He once downloaded an app on his phone capable of emitting frequencies from 1 to 22,000 Hertz, but that only tests the frequency range he can hear; it cannot fully measure the overall improvement of his hearing. He also tried using a fixed sound source as a reference, then increasing the distance to determine the maximum range at which he could hear it. But this method requires a relatively fixed, stable environment, is easily disturbed, and is difficult to test accurately.

The same applies to his sense of smell; both can only be subjected to relatively subjective, rough testing.

Lying on the balcony tiles, Xiang Kun closes his eyes, relaxes his muscles, and focuses his entire attention on his hearing and sense of smell—hearing as the primary, smell as the secondary.

Sounds suddenly rush in like a dam releasing floodwaters, a chaotic mix of noises, and the same is true for scents.

The human brain possesses a very mature mechanism for processing external information; one could call it a protective mechanism, or perhaps a lazy one.

When attention is not focused on sounds or smells, although the auditory and olfactory organs are constantly collecting information, this data is weakened, filtered, or even blocked by the brain.

Yet when attention is concentrated on these sounds and smells, the brain can focus on and enhance the transmission of the specific information being attended to, while shielding out other influences.

However, hearing a sound or smelling a scent and locking onto sensory information is one thing; how to make judgments based on that sensory information is quite another.

It is like a person sitting at home hearing a car roar past outside.

If his attention is drawn to the sound, the image of a car speeding down the road outside will subconsciously appear in his mind.

This image can appear because he is familiar with the road outside his home, has heard the sound of cars, and has seen them speeding by.

If someone is even more familiar with car engines and exhaust sounds, they might even be able to distinguish whether the car outside has a four-cylinder or six-cylinder engine, whether it is a Ford or a Toyota, a beat-up diesel truck or a supercar; the image constructed in their mind would be even more specific and rich.

And if this person sitting at home hears the crisp tap-tap-tap of footsteps upstairs, they will identify the sound as high heels. If they have never seen the neighbor upstairs, their mind might conjure an image of a young woman with long legs walking around in heels. But if they know the neighbor is a fifty-year-old woman, then hearing the sound of heels will trigger an image of a fifty-year-old woman walking.

The brain uses its own "database," experience, logic, and instinct to perform necessary "mental filling."

Therefore, being able to collect sensory information is one thing, but whether that information is truly useful in helping the brain make judgments is another.

The reason Xiang Kun lies directly on the floor is not because he lacks a chair to bring out or a blanket to spread, but because in a building made of reinforced concrete, aside from the air, the walls and floors are the primary mediums for sound transmission. Thus, by lying on the floor and making direct contact, he can more easily hear the sounds of the entire building.

Amidst the various chaotic sounds, Xiang Kun carefully distinguishes and slowly filters them. Starting with the closest sound—the apartment directly below, 608—he hears what seems to be a middle-aged couple discussing their son attending university in the north, while the television plays the evening news.

To the side, the neighbor's apartment is silent. No footsteps, no sounds of appliances, no talking, and no breathing can be heard, but there is the sound of curtains blowing; the windows are likely open, but the owner has not returned.

Then he hears the voice of the little chubby girl he saw during the day, Liu Shiling, and locates the source to 706—he knows the little girl lives in 706.

Judging by the sound, the little girl and her mother are at home. Her mother is urging her to take a bath, but she is lingering in front of the television, watching cartoons and refusing to move.

Using 706 as a reference point, Xiang Kun continues to distinguish the sounds he hears and makes judgments.

When he hears footsteps, he can use the structure of his own home and other reference sounds—such as the sound of a faucet turning on, a gas stove igniting, a cup being picked up, or other appliances being switched on—to determine where people are in their homes, and even the direction of their movement.

At the same time, he can use scents to assist his judgment. For example, hearing the clatter of a spatula against a wok in 402, combined with the scent he picks up, allows him to determine what dish they are cooking, and he can even guess the flavor profile with reasonable accuracy.

Moreover, the mutual verification of scent and sound helps him pinpoint locations more precisely.

Time passes bit by bit. From the outside, the lights in the residential complex slowly dim and decrease, and the sounds and movements from each household gradually subside.

It is past one in the morning when Xiang Kun finally opens his eyes, sits up from the floor, and stretches.

Using sound and scent, he has "toured" the movements of the entire building, visiting every single household. Although the only person he has actually met, knows by name, and can count as an acquaintance is the little chubby girl from 706, Liu Shiling, tonight he has recognized almost everyone through sound and scent, and even learned quite a few "secrets."

Of course, Xiang Kun does not do this to pry into others' privacy; he is conducting training.

Just as he began training for endurance and agility after increasing his muscle mass, now that his sensory abilities have rapidly improved, he needs to train his brain to process the sensory information he receives.

It is like two professional athletes with the same body weight and similar muscle content; because they engage in different sports and undergo different training, their methods of exerting force differ, and the results of that force naturally differ as well. A professional boxer's punch is naturally heavier than a professional basketball player's, while a basketball player's ability to execute basketball maneuvers under the same level of opposition is certainly stronger than a boxer's.

Therefore, Xiang Kun knows that having stronger sensory abilities is useless; he must practice and learn how to apply these powerful senses.

The first stage was collecting "samples" of sounds and scents he had never noticed before, building a "database," and turning it into an instinct for his hearing and smell—this is already more than half complete.

The second stage is what he is doing now: how to use sound and scent to help him judge the surrounding environment and situation, turning them into his "super eyes."

Don't be fooled by the fact that it takes him five or six hours to "tour" a building now; once he is familiar with it, perhaps in just a second or two, he will be able to quickly locate anyone in the building using sound and scent, and even build a real-time holographic image of the entire building in his mind.

Xiang Kun has already discovered that while his sensory abilities are evolving, his brain is evolving as well. At the very least, he no longer experiences the nausea and dizziness he felt at the beginning when immersed in multiple sounds at once.

At 7:30 the next morning, Xiang Kun puts on his gym bag and heads out, preparing to go to the gym. Although it is quite far from his previous gym—requiring a subway ride and a bus transfer, taking at least forty-five minutes—he does not intend to change gyms; after all, he has already paid for the membership and cannot get a refund.

Furthermore, he does not plan to take public transport; he intends to run there directly. The process of running is also a part of his training.

After stepping out, Xiang Kun happens to see Liu Shiling from 706 also leaving. Behind her is a plump young woman who bears a six or seven-part resemblance to her; it must be her mother.

"Baldy Uncle!" As soon as Liu Shiling sees Xiang Kun, she runs over to greet him.

Hearing this, her mother is immediately embarrassed and quickly follows, saying, "Oh my, I'm so sorry. The child doesn't know any better, calling people names like that. You must be the new tenant in 708, right? We'll be neighbors from now on. If you need any help, just let us know."

The little chubby girl runs to press the elevator button, while Xiang Kun chats with Shiling's Mother for a while. He learns that they only moved into 706 this year and that they own the apartment. Liu Shiling's father works in engineering and is often away, while Shiling's Mother is a full-time housewife, primarily focused on raising their only daughter.

Xiang Kun also gives a simple self-introduction, saying he is a programmer who has been working for seven years, though he does not tell her that he is currently unemployed.

They do not wait long. There are two elevators in this unit, and a descending one arrives quickly.

With a ding, the elevator doors open, but a dog's head pokes out, poised to pounce. Liu Shiling, who is standing at the elevator entrance preparing to enter, is startled and takes two steps back, nearly falling. Xiang Kun quickly reaches out to steady her.

Looking back, he sees a young woman in her twenties in the elevator, holding a leash attached to an adult Husky. The Husky is clearly very excited; as soon as the elevator door opened, it tried to lunge out. The young woman, who had been playing on her phone with one hand, barely managed to hold it back.

"PINKIE! PINKIE! STOP! Don't move!" The young woman switched to using both hands to pull the dog, shouting a reprimand.

However, the husky kept trying to get out, and the little chubby girl outside the elevator was clearly already terrified, looking timid as she hugged Xiang Kun's thigh, not daring to speak.

Shiling's Mother clearly knew this woman walking the dog, and frowning, she said, "Ms. Yang, you need to hold your dog properly. In such a small space as an elevator, with a dog this big and a child this small, what if it bites or pounces on her..."

Ms. Yang pulled on the dog without looking up and said, "It's fine, PINKIE just wants to play with the little girl, it won't bite, I'm holding it! ...PINKIE! STOP! SIT! SIT, quickly!!"

Shiling's Mother was clearly not complaining to Ms. Yang for the first time and knew it was useless, so she pressed the elevator button and said to Xiang Kun, "You go down first, we'll wait for the next one."

Xiang Kun, however, took the little chubby girl's hand and walked into the elevator together.

The little chubby girl had been a bit scared and reluctant to go in, but seeing the husky—which had just been so lively and eager to pounce, and which Ms. Yang couldn't hold back at all—suddenly shrink behind Ms. Yang, its head pressed tightly against the elevator wall as if it were trembling, she calmed down.

Xiang Kun turned back to Shiling's Mother and said, "It's fine, come in together."