Mothers are less disgust sensitive than childless females

Disgust is a basic emotion which motivates avoidance of disease cues. Females consistently display higher disgust sensitivity than males, although the evolutionary origin of this difference remains unclear. We examined the parental investment hypothesis, which posits that higher disgust sensitivity amongst females is adaptive since mothers may be more sensitive to potential pathogens which can negatively influence their offspring's survival. Contrary to the parental investment hypothesis, mothers demonstrated lower disgust sensitivity than childless females. Neither the total number of reported children, nor having at least one dependent child, resulted in heightened disgust sensitivity. Reduced disgust sensitivity may be caused by the source effect, which suggests that familiar stimuli are perceived to be less disgusting than unfamiliar stimuli. Lower disgust amongst mothers caring for a dependent offspring may facilitate cleaning of offspring's feces, dirty clothes or removal of uneaten foods.