A field experiment investigated violation of the spacing norm which keeps distance between people in a particular type of crowding, high social density, when the number of people in an area is large but space is not necessarily restricted. The proportion of people passing a drinking fountain who drank from the fountain was observed in conditions of high and low social density and, for each of these densities, when a confederate stood one foot from the fountain and when no one stood near the fountain. Three hundred passersby were observed in each of the four conditions. The observations supported the conclusion that the spacing norm was followed in low social density (p <.01) but violated under conditions of high social density for reasons other than lack of space. Interpretation focused on several concomitants of high social density, especially excessive social stimulation, and the accompanying tendencies to attribute less of the usual social meanings to people and honor fewer of their expectations.