The beauty-in-averageness effect stems from research showing that a blended face, a morph of multiple individual faces, is generally rated as being more attractive than its individual component faces.
But researchers Jamin Halberstadt, Piotr Winkielman, and colleagues found this effect to be somewhat puzzling, given the nature of morphed faces:
“As equal parts of two distinct individuals, morphed faces are maximally ambiguous regarding identity, and many theories associate ambiguity with negative affect.”
The researchers hypothesized that the beauty-in-averageness effect may depend on the fact that the original faces that go into the blend are typically unknown or are unrecognizable to participants. Given this, they predicted that people should find blended faces more attractive when their constitutent faces are unknown, but less attractive when the constituent faces are known and recognizable in the blend.
To test their hypothesis, they asked participants from The Netherlands and New Zealand to judge blended faces of local celebrities, people who are famous in only one of the countries. Their results are reported in Psychological Science.
As predicted, Dutch participants rated morphs of New Zealander celebrities as more attractive, but morphs of Dutch celebrities as less attractive, than the original individual faces. And the data showed exactly the opposed pattern for the participants from New Zealand.
Further analyses confirmed that the more participants recognized their local celebrities, the less attractive they found the morphs of those celebrities to be.
Halberstadt, Winkielman, and colleagues believe that their findings may reflect differences in processing fluency – a morph of familiar faces may be more difficult to process, for example, precisely because the constituent faces are at least somewhat recognizable.
“[A] morphed face represents a good and fluently processed example of a ‘face,’ but a poor and disfluently processed example of either of the individual faces from which it was created,” explain the researchers. “Fluent and disfluent processing could in turn produce positive and negative affect, respectively, that generalizes to the attractiveness of the blends themselves.”
Halberstadt, J., Pecher, D., Zeelenberg, R., Ip Wai, L., & Winkielman, P. (2013). Two Faces of Attractiveness: Making Beauty in Averageness Appear and Reverse. Psychological Science. DOI: 10.1177/0956797613491969