Dogs exhibit more jealous behaviours, like snapping or pushing their owner, when their owners displayed affectionate behaviours towards what appeared to be another dog compared to random objects. The study by University of California, San Diego psychology professor Christine Harris and former honours student Caroline Prouvost - is the first experimental test of jealous behaviours in dogs. The findings support the view that there may be a more basic form of jealousy, which evolved to protect social bonds from interlopers.