Hayduk (1985) investigated the ability of two models to account for a series of stop-distance measurements of personal space preferences. The repeated failure of the factor model implied that it was incorrect to interpret the multiple stop-distance measurements as reflecting a single, stable underlying characteristic called one's personal space preference. The success of the simplex model (a linear sequence of effects) indicated that personal space must be viewed instead as dynamic, which is in accord with the view that spatial preferences are situation dependent. The difficulty with the simplex model is that it is so sparse. Beyond its assertion of momentary expansions and contractions in spacing preferences, it seems to provide almost no theoretical flexibility. This paper demonstrates a range of theoretical styles (models) that are consistent with the simplex model, and hence documents a variety of theoretical and interpretational options that remain available to personal space researchers. Selecting among these conceptualizations of personal space will require further experimental investigations because all the equivalent optional models fit the current data equally well. Patterson's (1976) arousal attribution theory is used to illustrate how a theory postulating feedback loops might be consistent with the non-looped simplex model. Some intriguing parallels between these loop models and human physiology are also noted.