Photoshop :: Strange Border On Shape And Other Layers

I am working on a file. I have a background layer. I draw a shape layer, in this case a box, and when I do this layer has what almost looks like a drop shadow on two sides, ie the two edges have darker pixels than the shape color. I see the same sort of behavior on an image layer, in this case a photo, where the pixels on two edges, not the same edges, have different looking pixels. There are no effects on these layers.