Anya often says, you know, even if she gets into a dangerous situation, she’ll be fine because Mama will come to her rescue. She can smile and play around like that because Yor is her safe haven12


Both my brother and my dad are big, why am I the only one small?”

“Hmm, maybe it’s genetics?”


“Well, Grandpa is small, huh? But even before that, I’m small! Hahaha.”


“Why don’t you like being small?”

“…Because I can’t beat the big guys.”

“Just because you’re small, you can’t win? There’s not a single way to win?”

“Do you know? There may not be a certain way to get bigger, but there are many ways to get stronger… I’ve only talked about this with Hikaru, so now Hikaru is the first to be strong.”

[Conversation between Hoshiumi’s mother and child, Haikyuu]



Outgoing young people may enjoy going to mixers and parties, but introverted ones may find participating in such events painful.

Some people enjoy spending time reading, watching movies, or visiting art museums, while others find such activities boring.

The “environment” a person seeks is determined by their “temperament”.

This is called “niche picking”.

We choose places that suit us, consciously or unconsciously.

And what is most involved in this choice is “genes”.

As children grow older, they become able to choose their own “environment”.

On the other hand, young children have limited ability to choose their own “environment”.

In most cases, infants and toddlers go where their parents take them.

When taken to a museum, if the child and the parent enjoy spending time together watching dinosaur skeletons and machines explaining physics, the parent will want to take them to places that further stimulate their intellectual curiosity.

However, if the child runs wild in the museum and spends most of their time being scolded or apologizing to other visitors, the parent will hesitate to take them to museums in the future and will no longer think about taking them to places that stimulate their intellectual curiosity.

By showing some kind of behavior or attitude toward the given “environment”, children indirectly influence their experiences and experiences to fit their “temperament”.

However, in many cases, parents respond to such behavior or attitude by scolding them.



Imagine this.

Even though you are introverted, wouldn’t you feel uncomfortable if you were always going out to mixers and party venues?

Since infants and toddlers find it difficult to explain their feelings in words or to analyze why they are feeling unpleasant, they can only show their feelings through actions or attitudes.

The debate over whether “genes or environment” determines a child’s abilities, development, personality, etc., has continued to the present day, and the conclusion is that both “genes” and “environment” are involved, which is probably like, “Well, yeah.”

However, many people may not realize that “genes” are also involved in the “environment”.

“Parents’ genes” influence both the “environment prepared by parents for their children” and the “genes inherited by children”.

For example, let’s say there are parents with high IQs.

IQ is “inherited”.

Parents with high IQs are more likely to pass on high IQ “genes” to their children.

And parents with high IQs are also more likely to build households with many books.

Such parents will read books to their children and take them to places where they can learn.

In other words, children born to parents with high IQs not only inherit “genetic qualities” in terms of IQ, but also receive the benefits of both “excellent genes” and “enriched environment” through various activities that foster “creativity” and “logical thinking”.

Smart parents are more likely to help with homework, encourage their children to read books, and appreciate their children’s love of learning.

Children born to such parents receive the benefits of both “excellent genes” and “enriched environment”.

On the flip side, unfortunately, children may be subject to double negative influences.

For example, it is known that “aggression” is heavily influenced by “genetics”.

Children who inherit an aggressive “temperament” are more likely to have aggressive parents.

Therefore, they are more likely to be in a home environment that involves strict discipline or physical punishment, and such an environment further reinforces their aggressive tendencies.

Such children not only have a genetic predisposition to be short-tempered, but they are also placed in an environment that makes them even more aggressive.

Outgoing and impulsive parents tend to encourage their children to step out of their comfort zones and participate in challenging activities, such as skiing, diving, or rock climbing.

Introverted and intellectual parents tend to create places where their children feel comfortable.

They tend to have many books at home and read them with their children, and they tend to engage in quiet activities that can be done in small groups.

This is not about which one is good or bad.

Both types have their strengths and weaknesses, and a person’s “temperament” is not cleanly divided into extroverted or introverted, but is a mixture of various characteristics.

However, in many cases, the tendencies of our child-rearing are often reflected in the “genetic” “temperament” of the parents themselves.



…Meeting someone bigger or stronger than oneself, one realizes that one is small and weak…

“I’ve known that I’m weak for a long time.”

[Words of Hoshiumi from Haikyuu]