Doctoral Dissertation Research in DRMS: Testing the Effects of Facial Sexual Dimorphism on Men’s Selective Attention, Implicit Association, and Decision Making

Faces are the primary focus of attention during human interaction. Although humans find different people’s faces easy to recognize, faces are in fact highly variable. One way in which faces vary is on the masculine-to-feminine dimension.

Masculine faces are those with broader jaws, thicker brow ridges and longer chins than feminine faces. Studies have shown that people rate masculine faces as belonging to more physically dominant and aggressive individuals. These perceptions may affect decision making in everyday life, such as who we choose to lead organizations or perform certain tasks.

While previous studies have aided our understanding of individuals’ perceptions of dominance, it does not reveal why they do so. This project examines how faces differing in masculinity capture attention, affect memory, and impact perceptions of threat. A hypothesis is that faces with high levels of facial masculinity are perceived as more threatening and that this increases their attention and memory for them.

Results of this research have the potential to inform our understanding of the cognitive processes which underlie our face perceptions and provide a methodological basis to conduct future studies to understand why highly masculine individuals are treated with deference.

Experiments can provide tests of the effects of facial masculinity on observers’ dominance and threat perceptions. However, most experiments testing the effects of manipulating facial sexual dimorphism on observers’ perceptions have relied on forced choice paradigms, which have significant drawbacks. The current research uses an enhanced methodology to examine the hypothesis that human attention automatically prioritizes processing of masculine faces, and that observers’ selective attention to masculine faces is because they signal threat.

Participants in the study are college students. The basic experimental paradigm has participants complete self-reported ratings of physical dominance, state and trait anxiety levels, and their body dimensions (height, weight, grip strength and chest strength). These measures, collected prior to the experiments, are used to quantify participants physical dominance and anxiety and serve as covariates in the analyses.

Participants complete one of four experiments. Both the Dot Probe and Flanker Task test if participants selectively attend to masculinized men’s faces when they are not instructed to. For the Dot Probe task, participants are presented with two faces varying in masculinity, which is followed by the presentation of a target shape, either a square or diamond.

Participants must classify the shape as quickly as they can. For the Flanker Task, participants judge the orientation of a centrally presented target letter (i.e., upright, or upside-down) while ignoring flanking faces varying in masculinity. The lexical decision task tests whether participants automatically associate these faces with the concept of threat.

Participants judge whether a letter string is a word, while ignoring a simultaneously presented face varying on sexual dimorphism. A portion of the letter strings are words related to the concept of threat. Participants are assumed to be fastest to classify a letter string as a word when it is a threat word, and the presented face has been masculinized.

In the rating recognition memory test participants are presented with a sequence of men’s faces varying on sexual dimorphism and asked to rate how dangerous each man appears. Participants then complete a recognition memory phase, in which they are presented with another sequence of faces, some of which were presented in the rating phase, and asked to judge whether they saw each face in the rating phase.

Better memory for masculinized faces that are perceived as more threatening, assuming threat stimuli is more salient at initial encoding, is assessed with the recognition memory task.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.