> The woman operating the computer explained what I was to do. When she gave me a signal, I needed to look straight at the camera, then turn my head slowly and

> The woman operating the computer explained what I was to do. When she gave me a signal, I needed to look straight at the camera, then turn my head slowly and steadily to the right. I was then to turn at the same speed back to face the camera. Then I had to turn my head fully to the left, and back again to face the camera. At the same slow, steady speed, I was then to tilt my head back and look up, then to look straight at the camera. After that, I had to tilt my head down at the same speed and look toward the floor, and then to return to the original position. Finally, I was to slowly and completely open my mouth and hold that position. After I closed my mouth and looked steadily at the camera, my facial scan would be complete. All of these movements needed to be carried out in the assigned order in a single, uninterrupted sequence, two seconds per position. If any movement did not conform to the requirements, the computer would give a signal and stop running, after which I would have to start over from the beginning. > ... > My wife, who had been going through these procedures immediately after me, struggled when she came to the facial scan. The sequences for men and women differed in only one way: While men were required to open their mouths wide at the end, women had to close their mouths tightly and puff out their cheeks. I wondered what the reason was for this difference. Does anyone know the reason for the difference?