Just a thought........

[alexr]

This and statements like it, ie cows see things 10 times larger than we do etc, have always baffled me. How they KNOW that? Look through a pigeons eyeball???/ It's not how the birds brain translates it when it is alive. I'd like to know how come scientists can expound these theories with absolute certainty, when examoning a dead bird has no relation as to how the living birds brain /eye interface functions in life

 

If you look at the back of the eye you can distinguish two basic types of light sensitive cells rods and cones. One has pigments that pick up colour the other simply sees light and darkness. If you extract the pigments in these cells you can determine the colours that can be seen by the eye. Simple really. Whither the brain determines the colours seen as being red or blue or what ever is then irrelevant as the colours of the decoy match that of the real thing so will be seen by the pigeon as a pigeon. Perception and interpretation then becomes a mater for philosophers rather than scientists.

 

One interesting question you might consider is whither or not what you see as a cat is what I see as a cat. If you a brought up to interpret one set of visual inputs as a cat there is no reason to believe that your brains interpretation of that input uses the same pathways as my brain might use. However because the actual object is the same and ( despite your reluctance to admit that Yorkshire might have a similar cultural heritage as the rest of the country ) we are culturally instructed to accept that input as a cat, we would both see it as a cat.

[fullbore]

If you look at the back of the eye you can distinguish two basic types of light sensitive cells rods and cones. One has pigments that pick up colour the other simply sees light and darkness. If you extract the pigments in these cells you can determine the colours that can be seen by the eye. Simple really. Whither the brain determines the colours seen as being red or blue or what ever is then irrelevant as the colours of the decoy match that of the real thing so will be seen by the pigeon as a pigeon. Perception and interpretation then becomes a mater for philosophers rather than scientists.

 

 

I understand all that, but what I thought I had made clear in my op was that although pigeons might have the requisite number of rods and cones etc for scientists to surmise they can see in colour, doesn't mean they actually can. Science has no idea how the pigeons brain actually translates all the signals, Come to that, how do the then suggest they can see uv?

[poorwullie]

Follow on question for ten points.

 

Do fish sweat?

[alexr]

I understand all that, but what I thought I had made clear in my op was that although pigeons might have the requisite number of rods and cones etc for scientists to surmise they can see in colour, doesn't mean they actually can. Science has no idea how the pigeons brain actually translates all the signals, Come to that, how do the then suggest they can see uv?

I think that comes down to two things.

1) Experimentation. Use of UV stimuli producing either a directly observed responce, such as pecking at a UV marked trigger resulting in food, or the use of micro probes inserted into the vissual cortex producing a detectable change in electrical activity when UV stimuli are used.

2) An inherent belief that nature does not do some thing as complex as producing the mechanism for colour vision and then fails to wire it up

[George1990]