 Chaz Firestone and Brian Scholl have alleged that this fallacy has been the cause for mistaken thinking in perception research, including in studies that presumed to show that wearing a heavy backpack makes hills literally appear steeper, or holding rods outstretched horizontally would make doorways look narrower.In the example of holding rods outstretched, the original experiment had subjects evaluate the width of apertures (intended to simulate doorways), then show this width on a ruler held by experimenters.The width was evaluated as narrower by those holding rods than those who were not.