Date of Award


Document Type


Degree Name

Master of Arts in General Experimental Psychology



First Reader/Committee Chair

Campbell, Kelly


Recent studies suggest that genes may influence human mate preferences. What would this mean for same-sex siblings who share genes? Might they also share mate preferences and engage in mate poaching or would social norms and strong sibling bonds discourage such behaviors? We hypothesized that siblings would perceive their mate preferences to be more similar to their sibling’s than to an average person of their same gender. It was also hypothesized that the association between perceived sibling mate preferences and sibling mate poaching would be moderated by sibling closeness and sibling competition. Additionally, it was hypothesized that sibling mate competition would be negatively associated with participants’ investment in their niece(s) and/or nephew(s), that participants would report greater distress when thinking about a sibling poaching one of their mates compared to other relationship types and lastly, that men would be more likely to poach a sibling’s mate than women. No statistically significant difference was found between perceived similarity in sibling mate preferences and non-sibling mate preferences. We were unable to test the role of sibling closeness and sibling competition in sibling mate poaching due to low variability in the sibling mate poaching scale; however qualitative analyses provided insight regarding the prevalence of and circumstances surrounding sibling mate poaching. Other findings included a small, negative correlation between sibling mate competition and investment in nieces and nephews, greater distress reported when thinking about a sibling poaching one’s mate versus others poaching a mate, and no significant difference in sibling mate poaching scores for men and women. Study limitations and directions for future research are reviewed.