The surprising link between a woman’s body size and her jealousy levels

A study of women of reproductive age in China found that women perceive more feminine voices (of other women) as more jealousy-inducing. Interestingly, this effect depended on the body size of the woman experiencing the jealousy. Taller and slimmer women tended to feel more jealous than shorter or heavier women when another woman’s voice sounded more feminine. The paper was published in the PsyCh Journal.

Jealousy is an emotional response to a perceived threat to an important relationship or valued bond. It arises when a person fears losing attention, affection, commitment, or status to someone else. Jealousy can include feelings of insecurity, anxiety, sadness, anger, or resentment.

In romantic relationships, jealousy typically arises when an individual perceives that their relationship may be threatened by rivals who display traits signaling high mate quality (e.g., high physical attractiveness). These perceived threats elicit jealousy responses, which aim to safeguard the relationship from potential rivals.

Scientific findings indicate that the intensity of the jealousy response depends on the perceived mate quality of the potential rival. This is called the mate quality-jealousy hypothesis. The characteristics that signal mate quality tend to be characteristics that differ between the sexes (sexually dimorphic characteristics). According to this hypothesis, women will feel more jealous of other women who have more pronounced feminine characteristics, such as a more feminine voice.

Study author Cairang Guanque and his colleagues hypothesized that women would feel more jealous in situations where other women, whom they perceive as rivals, have more feminine voices. They also hypothesized that the intensity of this response would depend on the woman’s own body size.

Specifically, they believed that the association between the femininity of a rival’s voice and jealousy would be stronger in taller women and women with lower body weight and body mass index (BMI) values. The researchers theorized that taller, slimmer women—who possess traits culturally associated with high mate value—have more to lose if their high-value partners are poached, so they have evolved to be highly sensitive “threat detectors.”

Study participants were 134 heterosexual women between 18 and 40 years of age, recruited from a university campus in China. Their average age was 19.3 years.

In the scope of the study, participants listened to recordings of 131 women saying “Hi.” The study authors analyzed the recordings to precisely measure the acoustic pitch and formant frequencies (which dictate vocal resonance) to determine the level of femininity. They gave participants the following instructions: “You will hear women’s voices. Please rate how jealous you would be (from 1 = low to 7 = high) if she were flirting with your romantic partner. If you are not currently in a romantic relationship, please imagine that you are.” After this voice judgment task, the study authors measured the participants’ height and weight.

Results showed that, as expected, participating women did perceive more feminine voices as more jealousy-inducing. However, this effect depended on body size. Taller women were more sensitive to vocal changes in both pitch and formants, while slimmer women and those with a lower BMI showed increased sensitivity specifically to pitch variations. In other words, taller and slimmer women tended to feel more jealous than shorter or heavier women when a rival woman’s voice sounded more feminine.

“These findings indicate that body size significantly shapes individual differences in jealousy sensitivity during intrasexual competition. Our study supports the mate quality–jealousy hypothesis, highlighting how traits perceived as indicators of higher mate quality amplify jealousy responses,” the study authors concluded.

The study contributes to the scientific understanding of jealousy. However, it should be noted that the participants in this study were mostly 19- and 20-year-old students from a single Chinese university. Results in other cultures or among other age and demographic groups might differ. Additionally, the study only tested auditory cues in isolation, whereas real-world jealousy usually involves visual cues like facial attractiveness and body language as well.

The paper, “From Physique to Feelings: Deciphering the Body–Jealousy Connection in Women’s Responses to Feminine Vocal Cues,” was authored by Cairang Guanque, Chenle Xu, Chuhan Ji, Xingbang Ren, Xue Lei, and Chengyang Han.