What Colour is an Orange in the Dark:

Discussion in 'General Science & Technology' started by paddoboy, Sep 17, 2015.

  1. Write4U Valued Senior Member

    I also agree with the above, however, this does not address the mirror neural network, which seems to record not only the actual sensory experiences and the accompanying emotions, but also has an ability to recognize approximations to the actual experience.

    Does it make a difference if we see someone hurt them selves with a hammer or stab themselves with a knife. In both cases we seem to be able to associate these different actions as causing pain and triggers the same biochemical (emotional ) response of "wincing" in the observer as in the person who is physically experiemcing the pain. That is the foundation of "empathy" which then may result in "sympathy".

    I just wonder if such a mirror neural network can be fashioned in AI. Perhaps a rudimentary form of a mirror neural network may already be found in "spell checkers".
    Last edited: Oct 30, 2015
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  3. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

    I think in a hundred years or so AI may be able to make a "philosophical zombie" that exhibts human "pain behavior" etc but does not know what it is really like to have the qualia of pain. No collection of electronic hard ware and logic can know what it is like to be a bat. To know, you must be one.
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  5. DaveC426913 Valued Senior Member

    Yes. Good answer.

    The colour of an object is determined by the light shining upon it; the colour is influenced by the properties of the object.

    Grass that only receives red light is indeed black.
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  7. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

    No. You are under the influence of very imcomplete, thus wrong, theory. What is more astounding, not even aware of your own experiences.

    As the sun sets, they is very little green light in the direct rays - it has been scattered out during the long nearly horizontal path thru the air. Yet the grass still gives you impression it is green - not orange like the light falling on it.

    The brain does quite complex processing and reaches the true sensation even though the ilumination is far from white. It effetively computes the nature of the illunination and corrects for it. Do the expeiment.

    Only when there is monochromtic red light will you not precieve the grass as green and then it will not be black. Everything with reflection coeficients different for each wavelenght will have a different color percieved, even under monochromtic red light - just not their normal color, but certainly not black as if they were not there.

    "The colour of an object is determined by the light shining upon it." Completely FALSE.

    Read post 31, & 32 again.
  8. The God Valued Senior Member


    Even a subjective thing requires some kind of trigger. So, what probably you are trying to convey is that role of light (EMR) is just to cause stimulus on the retina, and subsequent processing by our visual system gives us the color perception.

    The frequency of light entering our eyes determines the color, that means different frequencies strimulate the retina differentially, which is then processed and transmitted forward. So it is quite possible that different people/animals see different color for the same frequency light. Orange may look violet to some animal, or medically our retina can be altered so that our color perception changes completely. Many animals can see UV light, I am sure the perception would be some kind of color only.

    Dreams: the necessary mandate for the dream is that resources must be present in our memory (and I am not talking about past life memory etc), some one dreams of being a superman, then the dreamer knows what a superman is, someone dreams of making it out with XYZ, then the dreamer must know about the making out as well as about XYZ, so if someone dreams of a colorful rainbow, then those colors must have been mapped in his memory, it has got nothing to do with visual perception. So dreams cannot throw any light on the color perception.

    But then there is Chromesthesia, hearing induced color perception, one form of it is rather sensory based color perception not necessarily in mind only, that means post retinal processing happens as triggered by audio, that competely agrees with your above statement. So I would say EMR is essential means to trigger the retina and subsequent processing gives the perception of color which could be different for different people (but mostly the same).
  9. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

    Only particially and usually there is a specrum of wavelengths entering the eye. What color you precieve depends upon the coefficients or reflectivity of adjacent surfaces as well as the distribution of wavelenths. For example no red light is need to percieve and apple is red. Land had a fanstastic demonstration of this years ago, which I saw in his talk at JHU>
  10. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member


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    note how broad the response of the eye's long wave lenght detectors are (so broad it is a mis-nomer to call them the "red detectors.") Any wave length between about 510 and 620 will cause those color sensitive detectors to respond - send neural impulses to the brain at least 50% as well as the peak red wavelenght does.

    That peak sensitivity is at about 580 but modern dielectric fillers can be inserted into a white light beam from a projector that completely block all wave lenght between 54o and 590, - all the light we normally called red.

    The removal of that red color band would of course lower the neural out put by at most 1/3, so about at most a 50% increase in the intensity of the white light from the projector, passing thru the "red blocking" filter, would restore the rate of neural discharges from the so-called red sensitive retinal cells.

    Your brain would not notice any difference. It only has the neural pulse rate to work from - judge the color being seen. That is not completely true as it routinely makes a comparison between all three different color sensitive cell's pulse rates. So to keep this constant too, the intensity of the projectors providing S and M peaking wave lengths must be adusted in neccessary relation ships to keep the relative strenght of all three pulse rates constant.

    The S wave length sensitive cells were not being stimulated by the light in the blocked band so their projectors adjustment would be a simple reduction of intensity by about 1/3,if the intensity of the projector making "red light" is not increaded to keep the neural activity of that red dectecor constant. The projector stimulating the green sensitive cells may need more complex adjustment - possibly in part by a wave lenght sensitive filter designed for keeping all its total output same as it was.

    As they say about skinning cats, there is more than one way to trick the brain into percieving red light that is not there.

    This is in essence what Land did more than 30 years ago to make me and most of the audience continue to see the apple as red when there was no light that one could call "red" falling on it.

    Most posting here have very little understanding of how complex the brain's processing for colors is, or what factors other than wave lenght also control, to a large extent, what color is percieved.
    Last edited: Nov 15, 2015
  11. DaveC426913 Valued Senior Member

    The sun's light, even at sunset, is still emitted across the spectrum. Thought the sunset appears quite orange, it isn't strictly orange light.
    And you will notice that grass at sunset is significantly darker.

    That being said, it will still appear green to your brain, because your brain automatically tends to compensate for colour cast. If you took a photograph, and checked the values, they would be grey. A grey object, in an otherwise orange scene, will appear green to your brain.
  12. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

    I think you are correct about a photographic color flim recording a color due only to the EM radition it is getting; but the brain is much more complex and many things besides the EM radiation entering the eye affect the color percieved. Read more here:https://en.wikipedia.org/wiki/Color_constancy and see ilusrations there too, for example the first one about colors on a hot air balloon being percieved to be the same even when part is in direct sun light and another is in shadow - very different EM radiation falling on them.
    Last edited: Nov 16, 2015

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