My Favorite Teacher and Crystallized Intelligence

My homeroom teacher in the sixth grade used to say, "You young teenagers are the best at studying. Once you become an adult, your memory capacity will steadily decline. So, study hard while you are still at an age where you can absorb anything."

Now that I have gone through my student years, worked for many years, and reached the age of sixty, what I think is that my teacher's words were a cliché—or perhaps a very common—sermon, filled with the general wisdom of the time, his own personal feelings, and love.

To be clear, I have no doubt that my teacher's words were filled with great and sincere love for his students. However, I also remember thinking to myself at the time, "People called doctors or scientists are all adults, aren't they? They all achieve deep learning and research after becoming adults." So, I concluded, "Yes, teacher, you want us to study. I understand, I will study. So you don't need to give such far-fetched reasons." I was satisfied with that conclusion in my own way. Again, to be clear, that homeroom teacher is still my "favorite teacher" to this day. Mr. Ota liked cigarettes. Even though he wasn't an art teacher.

In reality, it seems that behind the brain changes commonly described as a "decline in memory" lies the rise and fall of two types of intelligence.

It is said that in 1971, the year before I entered elementary school, a researcher named Cattell first proposed that humans have two types of intelligence—fluid intelligence and crystallized intelligence—and that each reaches its peak at a different time. The former refers to the ability to deal with new problems and logical thinking skills, while the latter refers to the ability to utilize knowledge accumulated through past experience and learning. It seems their respective productivity curves look like the diagram.

It says the peak of fluid intelligence is in the mid-30s. If so, the peak of crystallized intelligence is in the 70s. We who are around sixty have crystallized intelligence. Let's make use of it!

What? You ask what exactly crystallized intelligence is for? ChatGPT can tell you that!

(800 characters)

About this essay

Author's intention

The theme of the assigned book is study methods, but I was reminded of the words of my elementary school homeroom teacher, which symbolically and experientially expressed the "brain changes after becoming an adult," which is the angle and basis of the book. I also remembered that a book I read a while ago had an explanation about two types of intelligence, so I decided to conclude by appealing to the crystallized intelligence that increases after middle age.

Strictly speaking, memory capacity itself and fluid intelligence do not completely overlap, so I inserted "brain changes commonly described as a 'decline in memory'" where I changed the topic to try to prevent any nitpicking (laughs).

Also, I do not know if the brain changes mentioned in the assigned book are related to the change from fluid intelligence to crystallized intelligence. However, I judged that both are the same as brain changes that occur as one becomes an adult.

I tried to make the evaluation of my homeroom teacher, Mr. Ota, interesting by using extreme expressions, such as being harsh and expressing affection. The final conclusion was added as a follow-up to the natural question, "So what should I do with crystallized intelligence?" which I could not write due to the character limit.

Process to completion

I purchased the assigned book on Kindle on January 25th. It took me about two days to finish reading it by the end of the month. However, I couldn't come up with any ideas on what to write, and while I was thinking of letting it sit for a while, time passed in a flash and it became February 20th. It was three days before the deadline. Without any ideas, I squeezed out the episode about my homeroom teacher into the iPhone memo app as a starting point and started writing.

When I transferred it to my computer and started writing in Word, I remembered an episode about a middle-aged university student that was broadcast on TV when I was in elementary school as the next episode. It was a story about how even in middle age, one's mock exam scores are not inferior to those of current high school students. I added that and finished the 20th. The next day, I remembered the story of fluid intelligence and crystallized intelligence, and with that as the second half, the whole thing was completed. However, the character count was over, and when I read it deeply, I felt that the two episodes in the first half were not connected in content and there was even a dissonance. So, I deleted the episode about the middle-aged university student and completed it. I made fine adjustments on the 22nd to finish it. Furthermore, I wrote "About this essay."

I said I remembered and wrote about the two types of intelligence, but looking back after finishing, I feel like it was predicted that I would write this story immediately after finishing the assigned book. I also feel like the only reason I didn't start writing the teacher's episode was because of the prejudice that "it doesn't seem like I can write it very interestingly." Once I started, it was easier than I thought. I want to make use of this experience in the future.