In the short story "Pedestrian" by Ray Bradbury,"Regressive tendencies" pertains to Leonard Mead's walking at night while the other residents of the town sit before their television sets. In all the time that he has walked, he has encountered no one else. When asked why he is out, Leonard replies that he is walking; however, since no one else has walked for years, his behavior is considered "regressive"; that is, he has reverted to activities of the past, activities perceived as outdated and anti-societal.
In ten years of walking by night or day, for thousands of miles, he had never met another person walking, not once in all that time.
As Mead has walked along, he has peered into the darkened rooms of homes, addressing the occupants and asking them what they are watching, who has been shot,
and it was not unequal to walking through a graveyard where only the faintest glimmers of firefly light appeared in flickers behind the windows.
Inside the homes there appear to be only grey phantoms, lifeless creatures, sitting in darkened rooms, silent as they watch their television screens. The one man who is actively engaged in walking is the aberration, he is apprehended by the police and taken away for his "regressive tendencies."