Based on the experimental psychology literature, Zajonc suggests that animals (including human beings) are aroused by the presence of “conspecifics” (i.e., members of the same species). As puts it: “The presence of others as spectators or as
co-actors (…) increases the individual’s arousal or drive level.”Zajonc refers to the “sheer presence” of “individuals simultaneously engaging in the same activity in full view of each other”(our emphasis), which is the main characteristic of shopping together