Jemma Spike

And this is where we need to talk about where this number came from, because it didn't just magically appear randomly.

what really happened and what it all stems from is this singular study that was done actually i lie not a singular study it was a couple of studies there was one done in 1999 and one done in 2004 by the same group of researchers that looked at brain development from childhood to adolescence particularly what they were looking at was increases and decreases in gray and white matter

gray matter is responsible for a lot of our thinking, like it's called the thinking matter and decision-making and white matter is kind of what carries the messages between the different lobes or parts of your brain.

So if you were to see like a cross section of a brain, it's the white matter is a lot of the stuff in the middle.

And in these studies, they wanted to know when our levels of white and gray matter like reached peak maturity.

And

And so they scanned hundreds of brains, hundreds and hundreds to figure this out.

Here's the catch though.

The oldest subject, the oldest person whose brain they scanned, how old do you think they were?

21.

They were 21 years old.

I think there was a couple of other studies around that time that had a couple 22-year-olds, a couple 23-year-olds.

But those most prominent studies, firstly that one in 1999 and then the very famous one in 2004, the oldest participant was 21.

So where did that 25 number come from?

This 25 number that came from this research?

Well, it came from the author of the paper called Jay Geard.

I don't know if it's Geard, it's G-I-E-D-D.

And he basically speculated and he said, well, I guess it would be 25.

If we wanted, based on our research, if we wanted to guess when the brain fully developed, 25.

I would say 25.