Back in college, when I tried IQ tests for the first time, I used to clock close to 140 consistently in various tests. Recently, I tested my IQ in an app and it fell below 130 for the first time... I thought the app was not correct. So I tried it again in another online test. That gave a score slightly below 130 too. I was worried if I was becoming less intelligent a I got older. Then I took another test today and I got a 145. Here is the result of that IQ test
A normal intelligence quotient (IQ) ranges from 85 to 115 (According to the Stanford-Binet scale). Only approximately 1% of the people in the world have an IQ of 135 or over. Genius or near-genius IQ is considered to start around 140 to 145. Less than 1/4 of 1 percent falls into this category.
It looks like, it has got to do a lot more with familiarity with the tests and patience rather than actual intelligence. Back in College, I was very serious about these tests as I expected employers to test me on these. So I wrote these exams more carefully but when I tried in recently, I wasn't paying too much attention as I was merely checking out the app. Then when I tried it online, I was still figuring out the format. Now, the third time that I tried, I was more careful in my responses and I really was trying to perform well... just to reassure myself... and walah! here is the score. But again, it is just for the sake of reassurance. It doesn't mean anything. I haven't become smarter or dumber over the years, I have been using my intellectual faculties differently, which is not suitable to the IQ tests.
So don't worry if you score less on your IQ tests as you near 40 :) Just pay more attention.