What makes a terrorist?

After the London & Glasgow terror attacks, terrorism is on the front pages again. Now WSJ reports a study by Princeton economists that shows there is no provable link between poverty & terrorism nor between illiteracy & terrorism.
The London attack was planned by doctors & a new book theorizes that its not your income level or education that determines if you become a potential terrorist but the curtailing of civil liberties.
So how come China is not suffering this epidemic?
Have terror attacks increased or decreased since India's growth rate exceeded its innate 'hindu' rate of growth?
How is that most of the foot soldiers for various 'jehad', 'separatists' movements come from the underbelly?
What drives doctors or LSE grads or pilots to