What does the left thumb represent in divination?

The left brain controls the right side of the body and the right brain controls the left side of the body. The left brain is an abstract thinking area and the right brain is an image thinking area, that is, the left brain is rational and the right brain is perceptual. The person who crosses his hands and presses his right hand with his left hand is pressing his left brain with his right brain, indicating that sensibility is better than rationality. The right hand presses the left hand, that is, the left brain presses the right brain, indicating that rationality is stronger than sensibility.