Dog as Man's best friend? Not according to biases in episodic memory

Pet ownership is on the rise with pets often considered social companions. Across two experiments we use the self-reference effect in episodic memory to assess whether pets form part of an extended self in a similar fashion to close friends. Participants completed an online surprise memory task for adjectives encoded in relation to either themselves, a close friend, or their pet (experiment one) or with an additional celebrity encoding condition (experiment two). A self-reference effect was identified, such that self-encoded words were better recognized than both close friend, pet, and celebrity-encoded adjectives across both experiments. Crucially, close friend-encoded adjectives were better (experiment one), or similarly (experiment two), recognized when compared with pet-encoded adjectives. Pet-encoded words were recognized better than celebrity-encoded words. Pets may be extensions of the self, but not to a greater extent than close human friends.