Langlois and Roggman (1990) took facial photographs of males and females. They then created five groups of composite photographs by computer-averaging the individual faces. For one group the computer averaged 32 randomly selected same-gender faces, producing a quite recognizable face with average width, height, eyes, nose length, and so on. For the other groups the composite faces were averaged over either 2, 4, 8, or 16 individual faces.

Each group saw six separate photographs, all of which were computer-averaged over the appropriate number of individual photographs. Langlois and Roggman asked participants to rate the attractiveness of the faces on a 1–5 scale, where 5 represents “very attractive.” The data have been constructed to have the same means and variances as those reported by Langlois and Roggman.

Data on Rated Attractiveness Group 1 Group 2 Group 3 Group 4 Group 5 2.201 1.893 2.906 3.233 3.200 2.411 3.102 2.118 3.505 3.253 2.407 2.355 3.226 3.192 3.357 2.403 3.644 2.811 3.209 3.169 2.826 2.767 2.857 2.860 3.291 3.380 2.109 3.422 3.111 3.290 Mean 2.6047 2.6450 2.8900 3.1850 3.2600

(a) Specify a research hypothesis that could lie behind this study.

(b) Run the appropriate analysis of variance.

(c) What do these data tell us about how people judge attractiveness?