Chapter 17
Generally, intelligence is inherited.
According to modern neuroscience, genes related to brain development are concentrated on the X chromosome, so parents’ intelligence can be used as an indicator for predicting their children’s intelligence.
The correlation coefficient is about 0.5, I guess.
So the reason I feel smarter than I was in my past life is all thanks to Mom and Dad’s genetic influence.
So it’s reasonable to infer that Arin will also be smarter than the average child.
I noticed Arin’s talent while we were playing board games.
“Arin should get an IQ test too? A-yeon, is there a reason you suddenly thought of that?”
“I just noticed while playing a board game with Arin. She replayed the game in her head, and from the cards I’d already played, she inferred which cards were still left.”
“Card counting? Arin did that? Really?”
“Yeah. She memorized all the card types—one elephant, one lion, two giraffes—and tried to figure out my hand. I was surprised too.”
“…All right. Let’s have Arin take an IQ test too.”
✒️✒️✒️
The place we booked was the same psychological counseling center as last time.
Three years ago.
The place where I’d taken the Wechsler intelligence test and scored a perfect 160 IQ.
Pitter-patter-.
When I led Arin into the waiting room by the hand, Ms. Park Ji-su, who was handling reception, looked up.
“Oh my, Han Seol-ae’s mom?”
“Hello, Ms. Park.”
“It’s been a while. Oh my, Yoo A-yeon is here too! You’ve grown so much.”
Even after three years, Ms. Park Ji-su still remembered us.
Getting a perfect 160 on the Wechsler at twenty-six months old had been quite an unforgettable shock.
“H-hello, teach-er!”
I gave a little bow.
Ms. Park smiled warmly, then noticed Arin holding Mom’s hand.
“And this little one is?”
“She’s our second child. Her name is Yoo Arin.”
“Ah, so she’s your younger sister.”
Ms. Park knelt down to meet Arin at eye level and asked gently,
“Hello there, Yoo Arin?”
Swoosh-.
Arin hid behind Mom and grabbed the hem of her skirt.
“Arin, you need to say hello.”
“… H-hello…”
Her voice was uncharacteristically tiny.
As expected, Arin still lacked much experience with social interactions.
A child who had never ventured beyond the fence of family.
I started worrying whether she’d be able to handle a proper one-on-one test in a closed room with the psychologist.
‘Should I have built up Arin’s social skills and helped her overcome separation anxiety before bringing her in for the test…?’
Ms. Park Ji-su stood up again and said to Mom,
“Is Yoo Arin here to take the test today?”
“Yes, that’s right.”
“I understand. Please fill out these forms and wait a moment.”
Even the counselor seemed to be looking at us with some expectation.
✒️✒️✒️
Arin waited in the waiting room, holding Mom’s hand with her left hand and mine with her right.
Clammy~
The tension Arin was feeling was transmitted through her hand.
Before long, the door to the testing room opened.
“Yoo Arin, please come in.”
Squeeze-.
Our clasped hands tightened.
“Can Mom and big sister come too?”
“We’ll wait outside. It’ll be quick.”
“… How long do I have to wait?”
“Once Arin finishes the test with the counselor, Mom will be right here.”
“That’s right, Arin. Big sister won’t move from here at all!”
Even though we tried to reassure her, Arin’s lips kept wiggling as she trembled, unable to move.
It must have been scary, and the words she wanted to say probably wouldn’t come out properly.
I sprang up from my chair, then crouched down facing Arin.
“Arin.”
“… Yeah.”
“You know your big sister took a test here last time, right?”
“… Yeah. Big sis always bragged about having an IQ of one-sixty…”
“That’s right. It’s not scary at all. The counselor is super kind.”
Arin turned her head to look at me, then at the counselor, then at Mom, and then back at me.
“Really?”
“Yeah, really.”
“Really, really, really?”
“Yeah, really, really, really. And Arin.”
“Huh?”
“If you do your best on the test, I’ll do whatever you want for a whole week—building blocks, board games, drawing, anything you want.”
At those words, Arin’s eyes widened.
Then she squeezed our joined hands tightly.
“… Okay.”
A solemn resolve flowed from Arin’s eyes.
It was just as solemn as Guan Yu heading off to take an enemy general’s head.
Pitter-patter-.
Arin let go of Mom’s and my hands and walked up to the counselor.
At the door to the testing room, she looked back once.
Mom waved, and I waved too.
After making sure of that, Arin went through the door.
Click-.
“Haa…”
“Whew…”
Mom and I both let out a breath, as if the tension had finally left us.
“Mom, Arin’s really grown up now.”
“Thank goodness.”
The act of moving away from the fence of family.
The first step for a child to develop social skills.
Arin had just crossed one big mountain.
✒️✒️✒️
Two weeks had passed since Arin took the test.
We came back to the psychology center to hear Arin’s test results.
Ms. Park Ji-su spread the results sheet out on the table.
I stood on tiptoe and peeked at the results sheet.
Arin was still too short to see it.
…………………
Verbal Comprehension: 133
Visual-Spatial: 137
Fluid Reasoning: 160
Working Memory: 135
Processing Speed: 160
Full-Scale IQ: 145
…………………
“The overall score came out to 145. Statistically, that corresponds to 3 sigma. In percentage terms, it’s about the top 0.27%.”
“Ooh!”
I marveled.
As expected, Arin really is smart too.
Three sigma means that if you gathered 370 people, she’d be number one among them.
Of course, this big sister is four sigma, so if you gathered 15,787 people, I’d be number one~
Anyway, it was something to be happy about that my little sister was smart.
As I was thinking that, Ms. Park Ji-su continued.
“The important thing to note is that the gaps between the indices are large. Fluid reasoning and processing speed both hit the test’s maximum of 160, but verbal comprehension, visual-spatial, and working memory are relatively lower. The highest and lowest scores differ by 27 points.”
“Is that a problem?”
Mom asked with a worried expression.
“Rather than a problem...”
Ms. Park chose her words carefully and continued her explanation.
“In technical terms, it’s called asynchronous development. It’s a pattern often seen in gifted children, where one specific area develops explosively ahead of the others.
If the gap between indices is 20 points or more, you have to assume the full-scale IQ score doesn’t reflect the child’s actual abilities. In cases like this, it’s more accurate to interpret each index separately than to focus on the overall IQ score.”
As I listened to Ms. Park Ji-su, I sorted it out in my head.
‘So 145 is just an average score, and it doesn’t really show Arin’s true strengths.’
If I was an all-rounder with a nicely filled-out pentagon, Arin was the type with sharp corners.
Ms. Park Ji-su continued her explanation.
“What it means that fluid reasoning and processing speed are both 160 is that she’s exceptionally good at identifying rules and patterns and figuring out the best approach.”
“Then could verbal comprehension of 133 be a problem?”
Mom asked.
“No, not at all. 133 is still in the top 1 to 2 percent. It’s an excellent score. It only looks relatively low because it sits next to 160, and that’s simply because she’s still at an age where verbal experience is almost nonexistent.
Vocabulary and general knowledge are things that accumulate over a lifetime. Her verbal intelligence is already high; it just means she has only three years’ worth of verbal input so far.”
In simple terms, Arin’s hardware is outpacing her software.
Her brain is solid, but she lacks the knowledge to match.
I had the cheat code of memories from my past life, so I got a perfect score in this field, but if I’d lacked knowledge, I might have gotten a score similar to Arin’s.
“Children with this kind of profile usually react before they can explain things logically. If you ask, ‘Why did you do that?’ they’ll answer, ‘Because it felt like that’s what I should do.’
Intuition arrives first, and logic comes along afterward. In areas with clear rules, like board games or puzzles, children like this show overwhelming skill.”
I recalled the way Arin had been playing the animal card game.
Arin had memorized the animal cards and used a card-counting strategy to infer the remaining cards from the ones that had been discarded.
It wasn’t something Arin did consciously; it was the result of intuitively seeking the path to victory.
“One more thing: children like this often have another difficulty. The conclusion is already formed in their heads, but the speed at which they can explain it in words can’t keep up, which makes them very frustrated. That gap will naturally narrow as she gets older, but for now, you shouldn’t assume she doesn’t know something just because she can’t explain it verbally.”
Mom slowly nodded.
“Thank you for the kind explanation, Ms. Park.”
“Thank youuu—! Arin, you should say thank you too!”
“Th-thank you…”
Arin lowered her head, fidgeting behind me.
As we left the center, Arin asked with a puzzled expression.
“Big sis, I don’t understand what the counselor is saying.”
“She says Arin is super smart.”
“How smart?”
“Thiiiis much.”
I spread my arms wide to emphasize that it was that big.
Then Arin’s eyes sparkled brightly.
“It means she’s very special.”
“Special like you, big sister?”
At Arin’s question, I thought for a moment.
“She’s special in a different way from big sister.”
“How’s it different?”
“Big sister is good at lots of different things. But Arin is good at games with rules. She might even be better than this big sister.”
“Really? Then can I win the animal card game we played before too?”
“Yes. You can win. If not now, then later.”
“Really?”
“Really.”
Arin’s face lit up.
So that’s what it means to grin from ear to ear.
“Hehe. But for now, I win.”
“Just you wait, big sis! Hehe!”
Arin grinned from ear to ear and hugged me tightly.