阅读理解
Art, as we know, is subjective. What one person considers a priceless masterpiece others might see as nothing more than a giant black square. But there's one very specific kind of painting that almost everyone sees the same way-the kind with the" "strange" eyes that seem to follow you around the room. So what causes this optical illusion (视觉错觉) and how do artists achieve this effect?
It turns out, for even a moderately skilled artist, this effect isn't a difficult thing to achieve, In fact, the artists need to use a little illusion of depth, making the person depicted on the canvas appears somewhat 3D on a 2D canvas, and to adjust .the gaze (凝视) of the eyes so that they would be looking at someone standing right in front of the picture.
So what exactly is going on here in our brains that then makes it seem like the eyes follow you even if you move away from being front and center? As demonstrated by a team of researchers from Ohio State University, as you move to the side, the "near? and "far" points of the 2D image don't really change. These near and far points are defined as visible points that, if the image was 3D, would appear nearest and furthest away from the viewer at a given angle.
The idea is simple. No matter what angle you look at a paining from, the painting itself doesn't change. You're looking at a flat surface. The key is that the near points and far points of the picture remained the same no matter the angle the picture was viewed from. When observing real surfaces in the natural environment the near and far points vary when we change viewing direction. When we observe a picture on the wall, the visual information that defines near and far points is unaffected by viewing direction. Still, we willingly accept and interpret the thing in the painting as if it were a real object.
Thus, because the perspective, shadows, and light on the painting don't change as you move around, if the eyes in the painting would be staring directly at the observer who is standing in front of the painting, it creates something of an optical illusion in your brain so that the eyes will continue to seem to stare at you as you move to the side.
In contrast to the eyes following you trick, if the artist tweaks the painting a bit, for example the artist adjusts the gaze of the eyes so that the eyes are looking off somewhere else instead of directly looking at a potential observer, no matter where you stand, the eyes will never seem to be looking at you.
The technique first began popularly showing up in art around the 14th century when the artist and architect Fillipo Brunelleshi introduced the art world to the idea of "linear perspective", being painting with the idea of everything in the picture converging (聚集) on a specific point on the horizon, creating the illusion of depth. Linear perspective, combined with skilled use of light and shadow, allows artists to create masterfully realistic paintings, including sometimes of people that stare at you creepily no matter where you stand.