Objective: The aim of this study was to investigate asymmetrical interactions between humans and their environment using online seat booking sites. Background: Functional differences between the cerebral hemispheres affect the choices people make. For example, when asked to imagine going to a cinema, people preferentially select seats to the right. We investigated whether this experimental research generalizes to online booking sites for aircraft and theaters. Method: Occupancy rates for seats taken on the left and right sides were assessed for 100 airline flights with 12,762 available seats and 37 theater performances with 34,456 seats. On the basis of previous research, a rightward bias was predicted for aircraft and theaters. Results: For aircraft, contrary to expectation, occupancy rate was higher for left- compared with rightside seats. For theaters, a rightward bias was observed when the theater was less than half full. The bias was not affected by the orientation of the map. Conclusion: For aircraft, the leftward preference could be attributable to a rightward turning bias or a feeling that the port seats are closer to the exit, even though they are not. For theaters, the data demonstrate that the rightward preference observed in earlier studies exists only when the theater is relatively empty. Application: Asymmetrical seating may play an important role in the efficient assimilation of information from the environment, and this role should take this into account when designing effective humanenvironment interfaces. The online method of assessing seating used in the current study provides an informative and potentially powerful means of assessing asymmetries in human perception and action.