Foveal v's Peripheral Vision

When building your posture most of the emphasis is placed on bending from the hips and keeping the spine straight with the chin up ect.

However as you can see here with Adam Scott he has made changes to his posture over the years with consideration also being placed on the way he looks at the ball. You can see on the left his head position was more upright which makes him use his peripheral vision to look at the ball.

Whilst on the right he has rounded the top of his spine you can see the peak of his cap pointing down more thus allowing him to use foveal vision which is when you look directly through the middle of the eyeballs.