Muller-Lyer Illusion History and Use in Psychology

米勒-莱尔错觉是一种广为人知的视错觉，在这种错觉中，两条相同长度的线似乎具有不同的长度。这种错觉最初是由一个德国人创造的psychologist1889年被命名为弗兰兹·卡尔·穆勒·莱尔。

What Do You See?

In the image above, which line appears the longest? For most people, the line with the fins of the arrow protruding outward appears to be the longest while the line with the arrow fins pointing inwards appears shorter. While your eyes might tell you that line in the middle is the longest, the shafts of both lines are exactly the same length.

First discovered in 1889 by F.C. Muller-Lyer, the illusion has become the subject of considerable interest and different theories have emerged to explain the phenomenon.

How It Works

视错觉can be fun and interesting but they also serve as an important tool for researchers. By looking at how we perceive these illusions, we can learn more about how the brain and知觉过程work. However, experts do not always agree on exactly what causes optical illusions, as is the case with the Muller-Lyer illusion.

尺寸恒常性解释

心理学家理查德格雷戈里认为，这种错觉的产生是因为对尺寸恒常性尺度的误用。在大多数情况下，尺寸恒定性允许我们通过考虑距离以稳定的方式感知物体。

Other researchers contend that Gregory's explanation does not sufficiently explain this illusion. For example, other versions of the Muller-Lyer illusion utilize two circles at the end of the shaft. While there are no depth cues, the illusion still occurs. It has also been demonstrated that the illusion can even occur when viewing three-dimensional objects.

深度线索解释

Depth plays an important role in our ability to judge distance. One explanation of the Muller-Lyer illusion is that our brains perceive the depths of the two shafts based upon depth cues. When the fins are pointing in toward the shaft of the line, we perceive it as sloping away much like the corner of a building. This depth cue leads us to see that line as further away and therefore shorter.

When the fins are pointing outward away from the line, it looks more like the corner of a room sloping toward the viewer. This depth cue leads us to believe that this line is closer and therefore longer.

矛盾的线索解释

An alternative explanation proposed by R. H. Day suggests that the Muller-Lyer illusion occurs because of conflicting cues. Our ability to perceive the length of the lines depends on the actual length of the line itself and the overall length of the figure.由于一个图形的总长度比线条本身的长度要长，这会使带有朝外鳍的线条看起来更长。

“许多视觉错觉之所以如此有效，是因为它们利用了人脑反射性地处理信息的方式。如果一个幻觉能以这种方式吸引注意力，那么这就表明大脑会迅速无意识地处理这些视觉线索。研究人员迈克尔·普劳克斯博士解释说：“这也表明，也许视觉错觉代表了我们大脑喜欢看到的东西。”。