In one of the strangest findings in recent psychology, it seems the grouping of objects affects human decision making. Dubbed the group-contagion effect, it seems that when looking for objects with a negative connotation (defective or infected) people prefer to select from objects spaced further apart, and when looking for objects with a positive connotation (beneficial or desirable) people prefer to select from objects that are more closely packed.
The current explanation being offered is that we naturally imagine that the traits of objects transfer to their close neighbours - that is, closely packed objects are considered "contagious". But this explanation is just as weird as the phenomena: it might be logical if the people in question were arranging the objects, but why should it affect their decisions when choosing from pre-arranged objects?
It's another reminder that while we tend to believe our decision processes are logical, our subconscious and subjective beliefs are always working to sway our conclusions.