With wrinkles, it's the quantity, not their location, that ages you most

You emerge from bed, drag yourself to the bathroom and peer through heavy, hooded eyelids at the mirror. There to your horror you see last night's frivolities etched into your face: freshly dug, trench-like furrows, and spidery lines scrawled across your skin as if by a mindless, scribbling toddler. It's aged you by about ten years - or has it? Actually, the impact of wrinkles, both in terms of quantity and type, on perceptions of age has been little researched since the early 1980s [pdf]. According to a new study, however, it's the number of wrinkles you should be worried about, less so the location of them. But forced to choose, forehead, nose and mouth wrinkles are apparently more ageing than bags and wrinkles in the eye region.

Jose Aznar-Casanova and colleagues used computer software - of the kind used by the FBI for suspect photofits - to create several dozen male and female faces that differed systematically according to their number (one to four), depth, and location of wrinkles. The faces were all Caucasian, presented in grey-scale, with no hair or eyebrows - the idea was to try to remove the complicating influence of factors besides wrinkles on age judgments.

In an initial study, 99 participants from three age groups categorised these faces into one of eight age groups: child (3-12 yrs), teenager (13-19 yrs), young adult (20-29 yrs), adult (30-39 yrs), middle-aged (40-49 yrs), senior (50-69 yrs), sexagenerian (60-70 yrs) and elderly (over 70). In a second study, 22 students were presented with pairs of faces and had to estimate in each case the difference in age between the two.

So what did the researchers find? Unsurprisingly, faces with more wrinkles and deeper furrows were judged to be older. Moreover, the density of wrinkles had more of an effect on age judgements than differences in location of wrinkle. However, as mentioned, eye bags tended to have less of an impact on age judgments than other types of wrinkle, such that a face with eye bags/wrinkles was generally perceived as younger than an equivalent face with wrinkles to either the nose, forehead or mouth. There was also some limited evidence that wrinkles and shallow furrows aged male faces more than female faces. Overall, female faces tended to be perceived as younger than male faces. Finally, the age of the observer made a difference such that the younger participants - preadolescents and undergrads - tended to judge faces to be younger than did middle-aged participants.

With all the money that's spent in some cultures on cosmetic efforts to appear more youthful, you'd think more investigations would have been conducted into the precise factors that influence age judgements. This study makes a start but Aznar-Casanova's team acknowledged there's lots more work to be done: 'It is probably impossible to take into account, in one single study, all the information that a face can convey. For example, we did not present experimental stimuli in colour, nor did we include non-Caucasian faces, and we omitted hair and eye-brows from the faces.'
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Aznar-Casanova, J., Torro-Alves, N., & Fukusima, S. (2010). How Much Older Do You Get When a Wrinkle Appears on Your Face? Modifying Age Estimates by Number of Wrinkles. Aging, Neuropsychology, and Cognition, 17 (4), 406-421 DOI: 10.1080/13825580903420153