Studies have shown that highway drivers are less likely to drive at speeds greater than the posted speed limit if houses or buildings are in some way visible from the road. Assuming similar car, road and traffic conditions, highway drivers are more likely to drive at speeds in excess of the posted speed limit if the natural surroundings are not interrupted by buildings. Psychologists hypothesize that seeing signs of civilization reminds drivers of their responsibility to the safety of their fellow humans, thus making them more likely to obey the posted speed limit.
Which of the following, if true, most strongly supports the psychologists' interpretation of the study?