Dr Mark Shriver, who studies human origins at Penn State University, is interested in ancestry, variations in skin and hair colour, facial features and height.
Is it the colour of his clothes, the length of her arms or even the odd facial scar?
是衣服的颜色,手臂的长度,还是脸上略显古怪的伤疤?
3
In one study the person's gender was reported perfectly by 100 percent of witnesses, hair colour about 73 percent accurately, but facial hair almost always incorrectly.