The third aspect of the work of the mind is mind-control, the concentrating power. This is done in two ways: with the help of memory and with the help of mind. The concentration that is performed with the help of memory is a negative or passive concentration. It requires little effort to concentrate with the help of memory. The Hindus taught this by placing certain gods and goddesses before a person and telling him to look at them and then to close his eyes and think about them. By looking at a certain object the memory reflected it, and that reflection was the concentration.