A social-scientific study, in which participants viewed photographs of persons over the age of seventy in order to assess visual signs of age in the elderly, has concluded that,
The main indicators of age are biological: skin, eyes and hair colour — but supplemented by vigour, style and grooming. 
It is to be hoped that this study will finally put to rest the long-standing hypothesis that it is principally cardigans and soup-stains that give the elderly away.
 Helle Rexbye & Jørgen Povlsen, “Visual Signs of Ageing: What are We Looking At?”, International Journal of Ageing and Later Life, Vol.2:1, 2007, pp.79-80. (According to the authors, the study has value because it “questions a postmodern [Baudrillardian] fluidity of visual signs — at least when the concern is signs of ageing.” (Ibid., p.80.) Are we really at the stage where scientific research is required to re-affirm the obvious in the face of the absurd?)