Octovision and Patterns of Confusion
Octopuses are color blind. It says so right here in the paper:
Evidence that Octopus is Color Blind
The paper was written in 1977 by a J. Messenger. It does acknowledge that the test was only with some colors and one species. The title makes no such distinction.
This morning, I watched a Science Channel presentation on octopuses. "Octopuses are color blind," the narrator intoned. It was done with the same flat style as assertions on the same channel that climate change was doing irreparable damage to the Earth.
The 1977 paper above tested one species, with only certain colors, and ignored that octopuses generally see three types of polarization as well. Much more recently, I still see statements like this on threads for octopus enthusiasts: "Well yea, they say that Watasenia scintillans otherwise known as the firefly squid are the only cephalopods with colour vision, so far..."
This apparently comes from Wikipedia, which states: "The Sparkling Enope Squid [Firefly Squid] is the only species of cephalopod in which evidence of color vision has been found."
We have this reference from the science website AbsoluteAstronomy:Surprisingly in light of their ability to change color, most [cephalopods] are probably color blind - certainly all octopus are.
That use of "certainly" seems inappropriate for a science site.
With all of these assertions that all octopuses are color-blind, it seems a dreadful oversight not to have told the octopuses themselves: Color Discrimination Conditioning in Two Octopus Octopus aegina and O. vulgaris.In the transposition tests, O. aegina showed correct responses at 70-100% to the blue ball irrespective of the shades of grey employed, implying the possession of color vision.
That paper demonstrates that color vision varies between species. (It also might vary among individuals, just as it does with us.)
That Octopus Aegina, the "marbled octopus," does a pretty good job of blending in with the color of its surroundings:
"Octopuses are color-blind" is the common thing to say about the topic. And I noticed that one of the experts presented in the documentary this morning was a J. Messenger, just like the author of the 1977 paper and perhaps the same person. How much would it have harmed the presentation to have said "Some (or even Most) species of octopus appear to be color blind" instead of that blanket, wrong, statement? And I wonder about Dr. Messenger; is he still convinced of his original assertion? Would he approve of that narration?
I was amused at two aspects of that 1977 research: One of the eight octopuses decided not to play with the doctor, and refused to participate in the games. Another one apparently got disgusted with the proceedings and left -- it escaped from the tank. So they continued with the six that were willing to go along with the tests.
The second aspect that amused me was the identification of a skin coloration that indicated that the octopus was struggling to decide what to do, the "conflicted" pattern. In my own story, the descendants of creatures like this express their feelings that way. "Conflicted" is a lot more subtle than simply "scared" or "relaxed."
===|==============/ Level Head
Evidence that Octopus is Color Blind
The paper was written in 1977 by a J. Messenger. It does acknowledge that the test was only with some colors and one species. The title makes no such distinction.
This morning, I watched a Science Channel presentation on octopuses. "Octopuses are color blind," the narrator intoned. It was done with the same flat style as assertions on the same channel that climate change was doing irreparable damage to the Earth.
The 1977 paper above tested one species, with only certain colors, and ignored that octopuses generally see three types of polarization as well. Much more recently, I still see statements like this on threads for octopus enthusiasts: "Well yea, they say that Watasenia scintillans otherwise known as the firefly squid are the only cephalopods with colour vision, so far..."
This apparently comes from Wikipedia, which states: "The Sparkling Enope Squid [Firefly Squid] is the only species of cephalopod in which evidence of color vision has been found."
We have this reference from the science website AbsoluteAstronomy:Surprisingly in light of their ability to change color, most [cephalopods] are probably color blind - certainly all octopus are.
That use of "certainly" seems inappropriate for a science site.
With all of these assertions that all octopuses are color-blind, it seems a dreadful oversight not to have told the octopuses themselves: Color Discrimination Conditioning in Two Octopus Octopus aegina and O. vulgaris.In the transposition tests, O. aegina showed correct responses at 70-100% to the blue ball irrespective of the shades of grey employed, implying the possession of color vision.
That paper demonstrates that color vision varies between species. (It also might vary among individuals, just as it does with us.)
That Octopus Aegina, the "marbled octopus," does a pretty good job of blending in with the color of its surroundings:
"Octopuses are color-blind" is the common thing to say about the topic. And I noticed that one of the experts presented in the documentary this morning was a J. Messenger, just like the author of the 1977 paper and perhaps the same person. How much would it have harmed the presentation to have said "Some (or even Most) species of octopus appear to be color blind" instead of that blanket, wrong, statement? And I wonder about Dr. Messenger; is he still convinced of his original assertion? Would he approve of that narration?
I was amused at two aspects of that 1977 research: One of the eight octopuses decided not to play with the doctor, and refused to participate in the games. Another one apparently got disgusted with the proceedings and left -- it escaped from the tank. So they continued with the six that were willing to go along with the tests.
The second aspect that amused me was the identification of a skin coloration that indicated that the octopus was struggling to decide what to do, the "conflicted" pattern. In my own story, the descendants of creatures like this express their feelings that way. "Conflicted" is a lot more subtle than simply "scared" or "relaxed."
===|==============/ Level Head