Naked Science Forum
General Science => General Science => Topic started by: Aquila on 11/01/2008 17:38:45
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Is it true that we see black and white when we find ourselves in life-threatening situations and have to take quick decisions?
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No.
I've been in a few life-threatening situations while driving in our northern winters- ever drive on "black ice?" - and while having the sense of time "slowing down," I have never lost color-vision. I'm curious where you heard this.
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I have heard that in those moments when you feel your life highly threatened, your brain tries to cope with the increasing amount of data that should be handled in that very short period of time.
Therefore, it tries to get rid of some of the information that may not be very useful, so it will have processing power left for perceptions that seem to be imperative (like feeling the body`s position in space).
Thus, the energy-expensive processing of colours is eliminated. At least that`s what some scientists claim.
I had seen a documentary (i do not remember the name), that, unfortunately, only referred to this issue for about 2 seconds, but it was enough to get my attention. So, here i am, curious about what others think about this. I think that if this is true, then we should be in possession of an incredible technique that our brain uses when confronted with imminent danger. I find this fascinating and i`m willing to know more about it.
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Hi Aquila and WELCOME to the forum.
I am trying to think back when on the odd occasion I have been scared for my life and I sincerely do not recall a loss of colour. Perhaps with me the threat was not real enough.....but...surely sight is paramount in the majority of those incidents......on the other hand........is black and white clearer than colour images ?
Interesting topic.
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I also have been in those circumstances and never lost my color vision at all.
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I've been in a few and I never lost the ability to see in color either.
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Thank you for the warm welcome!
Surely sight is paramount in the majority of those incidents, but i think an explanation to the black and white vision reports (there certainly have been a few) may be that we instinctively try to widen our visual experience over the environment at that moment. Therefore, considerably more information is sent to the brain from the periphery of the retina, where there are no cone cells responsible for coloured vision. If the brain concentrates on that, then the image will seem to be black and white.
Also, rod cells from the retina are more sensitive to light (they are responsable for scotopic vision) and they make peripheral vision very sensitive to movement. Although rod cells are not very efficient on getting detailed images, they confer achromatic vision, with more emphasis on detecting motion, which our brain seems to badly need in those long seconds. So we do not see a clearer image but we perceive a less detailed one which the brain is capable to quickly analyse.
What do you think?
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It all seems reasonable to me....perhaps the "colour" of the moment is lost during the instance of potential 'life loss' and that we just do not notice that it's turned to B & W !..after all..it's all over probably so quickly !!
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Consider me a "skeptic" here. I really can't see how cone deactivation would impact one's ability to better handle a split-second life/death situation. My own lack of such an experience aside, why aren't there anecdotal accounts of others such as fighter-pilots, etc having this experience?
Having said that, I'm willing to eat some crow here if someone can find some evidence that this actually occurs, even rarely...I did a cursory search and came up empty-handed.
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I rather suspect it depends on the nature of life threatening situation.
Firstly, the amount of information being sent to the brain is not an issue, because much of the information is already preprocessed by the eye, and then will be processed in different parts of the brain, so I cannot see bandwidth being increased by shutting off colour vision.
What may be that as one is losing brain function, as one is on the brink of death, parts of the brain start to switch off, and this may effect colour to some extent, but it rather depends on which parts of the brain is switched off (certainly, a similar phenomena is known with regard to sound processing remaining active even when one is no longer capable of processing vision - such as when partially under anaesthetic). One thing we could imagine that since rods are used for low light vision, if one's vision is failing, it may be that the rods persist in vision at low efficiency, even as the cones are no longer able to see anything with their reduced efficiency.
What is true is that peripheral vision is more dominated by rods, and so monochrome; while central vision has far more cones, and is the dominant area of colour vision. Whether, when under stress, one tends to become more aware of peripheral vision, I cannot say (it may be, that in certain types of threat, one may become more aware of movement in the periphery of our vision, as maybe this is where we imagine the threat to originate).
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Well my memory (as we all know) is not too good, but i can never remember my vision changing to black and white when being in a life threatening situation.
I have been deliberately run over, shot at, present when an IRA cell have been arrested and, rather stupidly, ran in to the back of a stationary car on a push bike. Each 'incident' has had it's own physical and psychological effect but never a change in vision.
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Some people also stated that they have experienced tunnel vision under high stress conditions. In medical terms, tunnel vision is the loss of peripheral vision with retention of central vision, resulting in a constricted circular tunnel-like field of vision.
Considering the fact that usually 90% of the total information we get about our environment comes through our eyes, under high stress the brain may want to reserve more than 10% for some other afferent sensory channels, thus reducing our field of vision (or the quality of sight - black and white vision).
Another possible reason for those phenomena is that when we find ourselves suddenly in a critical situation, more blood is directed to the muscles, this resulting in temporary loss of blood flow to the brain. Therefore, sight is likely to be affected, generating tunnel or black and white vision.
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Isn't it mainly a matter of how we remember a scary event?
Unless the colour experience of a dodgy situation was very relevant, one would be more likely to remember other, more important information - like the size of the tiger's teeth and claws, rather than the colour of the wallpaper.
They do say that we are very conscious of red, as a sign of danger - a glimpse of blood would mean we could be in for a spot of violence in the near future. Colour vision would be a help here.