Can one significantly increase his/her intelligence during his/her adult life? There are so many people who while growing up have not had the opportunity to develop their potential because of stupid parents, unhealthy life styles, psychiatric drugs, poverty, etc..Even more frustrating is how our ability to learn decreases as we age, as if mother nature was telling us: 'you didn't make it then, now deal with it!!'
Of course, intelligence (defined as the ability to understand) can be greatly improved during one's lifetime.
However, it is very difficult, if not impossible, to achieve anything without aiming for it. Once we establish a need to Understand - it is up to us to determine the amount of effort, make the committment and then act on it.
Needless to say, we have the Freedom of Choice to do whatever we feel like. The easiest thing of course is not to do anything...
In essence, if you make an effort to understand something today, no matter how elementary, and you achieve it - you increase your ability to understand other things tomorrow. As you know, lifetime has many days...
I disagree that the ability to Understand decreases with age. It does only for those, who stop learning and/or misuse their potential. @2000 years ago a great man expressed it as follows  "Whoever has something will be given more, and whoever has nothing will be deprived of even the tiny bit that person has..."
In essence "use it or lose it" principle of Nature seems to apply not only to muscles, but also to our Intellect.
I totally agree. Members of my family use to say: 'at the age of 14 it is easy to learn languages, but at 40? No chance'. I then think: 'This is not due regressed intellect, but lifestyle and the missing effort to even start learning.' My grandma, (84 right now), started to re-learn the french language, because she had forgotten most of it. 'I want to improve my French', she says, 'because I learned it 40 years ago, I forgot some of it..'.
I always wondered why my grandma got her first grey hair at the age of 70, when I know people, who got them in their early 40's and 50's. It seems that using one's mind has also a positive effect on one's body. Let's keep thinking... [paul]
Is it possible to develop intelect without interacting with other individual intelects?I heard there are some yogis that live alone all their lives in the mountains and they are very wise and advanced spiritually. How is that possible?
Intellect can only develop ITSELF. Evolution of Intellect is a result of entirely individual effort.
A good company can be thought provoking and quite stimulating, but a lack of it is not an obstacle in Thinking and Understanding. On the contrary. A lack of clutter brought in by other people can be quite beneficial...