This is false. I frequently find myself annoyed at my AC because it only has settings of 72°F and 74°F, and they are a little too cold and a little too warm for me. I want 73°F. When it's around room temperature, you can absolutely tell the difference.
The further away from room temperature, the less we can distinguish. All our senses work logarithmically like that.
The further away from room temperature, the less we can distinguish. All our senses work logarithmically like that.