How facial aging affects perceived gender: Insights from maximum likelihood conjoint measurement
Conjoint measurement was used to investigate the joint influence of facial gender and facial age on perceived gender (Experiment 1) and perceived age (Experiment 2). A set of 25 faces were created, covarying independently five levels of gender (from very masculine to very feminine) and five levels of age (from very young to very old). Two independent groups of observers were presented with all possible pairs of faces from this set and compared which member of the pair appeared as more feminine (Experiment 1) or older (Experiment 2). Three nested models of the contribution of gender and age to judgment were fit to the data using maximum likelihood. The best fitting model of the three was decided by likelihood ratio tests. Both gender and age contributed to the perceived gender and age of the faces. For judgments of gender, an additive model was rejected in favor of a saturated model in which responses depended on the levels of gender and age. In particular, faces were perceived as less feminine as age increased, but this trend was more pronounced in feminine faces compared to androgynous or male faces. For judgments of age, an additive model was rejected in favor of a saturated model for only half of the observers. For the other half of observers, perceived age increased as the faces become more feminine. Taken together, the results entail that: (a) observers integrate facial gender and age information when judging either of the dimensions, and that (b) cues for masculinity and cues for aging are positively correlated. This correlation exerts stronger influence on female faces, and can explain the success of cosmetics in concealing signs of aging and exaggerating sexually dimorphic features.