Opponent process theory: why do I see green after looking at white?

In summary, the conversation discusses the experience of seeing a green and then purple patch on the ceiling after staring at a bright light. The person questions why the colors appear and how it relates to opponent process theory. The other person responds by explaining that this phenomenon is due to adaptation to bright lights and the different speed of adaptation of the three photoreceptor types in the eye. They also suggest that certain eye conditions or deficiencies may contribute to this experience.
  • #1

DeuteriumDude

35
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This morning, I was lying on my bed, looking at the bright morning light coming in through the window. The blinds (which are white) were at least half shut, so much of the light was filtered through them. I then stared up at the ceiling, and saw a nebulous patch of green. I shut my eyes, and the nebulous patch of green became clearer still. I then reopened my eyes, looking again at the ceiling, and the nebulous patch became purple.

Here's what I don't understand: shouldn't the nebulous patch be black, since I was originally looking at something white? A green patch should be left by staring at purple. There is nothing purple in my room or outside my window. And yet, I've had this happen to me before while reading a book under bright sunlight: eventually, everything in my field of vision will look green. Also, why does the nebulous patch turn purple when I shut and reopen my eyes? None of these things seem to follow the predictions of opponent process theory.
 
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  • #2
My first thought is that you are seeing green in response to red; the eyelids are very thin and full of blood vessels, so if you close the lids while strong light is shining on them, you may be aware that the darkness under the lids is red-tinted if you have the eyes positioned as if to see (not rolled back).
 
  • #3
Dude, take care of your eyes. :wink:

DeuteriumDude said:
Here's what I don't understand: shouldn't the nebulous patch be black, since I was originally looking at something white? (...) Also, why does the nebulous patch turn purple when I shut and reopen my eyes? None of these things seem to follow the predictions of opponent process theory.
Well this theory is about color perception in steady condition, while here you're playing with adaptation to dangerously bright lights. I'd guess the green switching to purple comes from the relative speed of adaptation of the three photoreceptors types, especillay the blue ones versus the two others.
 
  • #4
Dude its very normal its just impression of bright light which remains in eyes its happens to indivisuals whose eyes are more sensetive to light like high myopics,or people with vit A Deficiency,zinc deficiency
 

1. What is opponent process theory?

Opponent process theory is a psychological theory that explains how our visual system perceives color. It states that there are three opposing pairs of colors: red-green, blue-yellow, and black-white. These pairs work together to create color vision and explain why we see certain colors after looking at others.

2. How does opponent process theory explain why I see green after looking at white?

According to opponent process theory, the color green is represented by one half of the red-green pair. When we look at a white object, all three pairs of colors are stimulated equally, resulting in a neutral response. However, after staring at white for a prolonged period, the red-green pair becomes fatigued, causing the green to become more dominant. This is why we see a green afterimage.

3. Is opponent process theory the only explanation for afterimages?

No, there are other theories that attempt to explain afterimages, such as the trichromatic theory and the retinex theory. However, opponent process theory is widely accepted and provides a comprehensive explanation for afterimages and color perception.

4. Can opponent process theory also explain why I see other colors after looking at bright objects?

Yes, opponent process theory can also explain why we see other colors after looking at bright objects, such as yellow after staring at blue. This is because the blue-yellow pair is also stimulated and fatigued in a similar way to the red-green pair.

5. Does opponent process theory have any limitations or criticisms?

Some critics argue that opponent process theory does not fully explain color perception and afterimages, as it does not take into account other factors such as individual differences in color perception and cultural influences. Additionally, some studies have found evidence that contradicts certain aspects of the theory. However, overall, opponent process theory is still widely accepted and continues to be a valuable framework for understanding color perception.

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