"Myth Busting" by The Human Tetrachromacy Research Collaborative: Toppling myths surrounding potential human tetrachromacy...

The contents of this website are subject to copyrights protections of Creative Commons International License 4.0 to Kimberly A. Jameson, September 18, 2014. UC Irvine.

MYTH #1. The "100 Million Colors" idea:

The truth is, based on scientific experiments that have been done on human color vision, no one knows if human tetrachromats can see 100 million colors -- or even exactly how many colors a human tetrachromat can perceive. In fact, to my knowledge, no scientist has ever suggested the existence of such an empirical result (let alone demonstrated proof of "100 million colors" in a journal publication). The notion that 100-million colors is the consequence of expressing an extra photopigment class in one's retinas most likely comes from the over-simplification and over-generalization of a theoretical model. That is, it is based on an extrapolation of a theory involving the geometric expansion of visual capacities that are thought to arise with the addition of spectrally different photopigments when moving from dichromat observer types (a system involving 2-photopigment retinal processing) to trichromats (a 3-photopigment system) and on to tetrachromats (a 4-photopigment system). The geometric expansion theory is introduced briefly in the context of color vision by the excellent research team of Neitz, Carroll and Neitz (2001). Article found here. See Figure 3, and on p. 31-33 of the article entitled "Almost Reason Enough for Having Eyes." J. Neitz, J. Carroll, M. Neitz - Optics & Photonics News, 2001.

The first media mention of this magical "100 million colors" number seems to have occurred as a simplified interpretation of this geometric expansion theory found in a news article in 2006 appearing in the Pittzburg Post Gazette: Original news item found here.

This PPG news item featured an interview with Dr. Jay Neitz and the topic of his color vision genetics research. The PPG piece implies that Neitz said "100 million colors" in the same breath as human tetrachromacy, although what they write is not presented in quotations as if it was his very words. Instead it summarizes what he "said", and in that way connects tetrachromacy with the 100-million colors idea, and, if you read both the PPG piece and the Neitz, Carroll and Neitz (2001) article, you'll see there's a good chance that because of their fervor an oversimplification in quantifying ensued, and with the push to publication, some misinterpretation or loose quoting likely occurred as a result of such zeal. Just pointing out here the difficulties of blending science with popular media when constraints of news reporting are in operation.

Of course, given the power of the internet, the simple idea of "100 million colors" went viral as human tetrachromat news because, in part, it's an easy sound-bite that takes home a big message in real terms. In fact, there is no scientific basis for anyone to say that tetrachromats see 100 million colors -- I've not been able to find a scientific report that says anything even remotely like that. That number comes from theory - out of an arithmetic generalization of what might be possible if one were to build a tetrachromat robot with perfect processing and no signal information loss or compression. But, we all know theories are not always shown to be 100% accurate after actual testing, and, chances are, given what we know about how human processing channels combine information, the potential for human tetrachromats to differentiate on the order of "100 million colors" is probably not a realistic estimate, and is most likely a gross overestimation.

BOTTOM LINE: The "100 million colors" number comes from theory that assumes perfect neural processing, and human neural processing systems are notoriously imperfect. Also, there is the common-sense argument: Would it not be the case that if it were really 99 million more colors than normal, a human tetrachromat difference would have been absolutely trivial to show in an experiment? Well, as it turns out, it is not at all easy to show differences in color perception for potential human tetrachromats. So, why does the idea persist if it's not actually true? Perhaps, because it's easy to write about and digest, and people like to hear the "100 million color" idea because it's quantified, it's catchy, easy, uncomplicated. Generally, misconceptions of this sort are not unusual in public communications of results at the early discovery phases of phenomena. Scientists and media reporting will, given time, shake out the wheat from the chaff, good ideas will replace those that are less good. And hopefully as we learn more about potential human tetrachromacy there will be other interesting details to discuss, and explanations to give, and they will replace "100 million colors" idea for tetrachromacy with empirically demonstrated results and proven facts.

Return to The Human Tetrachromacy Research Collaborative page.

MYTH #2. The idea that the potential for human tetrachromacy is "only possible in women":

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BOTTOM LINE: The proven facts.

Return to The Human Tetrachromacy Research Collaborative page.

MYTH #3. The idea that the real-world objects affording a potential human tetrachromat the ability for tetrachromatic color perception are "natural" as opposed to "man-made" objects:

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BOTTOM LINE: The proven facts.

Return to The Human Tetrachromacy Research Collaborative page.

MYTH #4. Human tetrachromats can perceive more color in industry-standard RGB film photography and images than do normal color-vision human trichromats:

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BOTTOM LINE: The proven facts.

Return to The Human Tetrachromacy Research Collaborative page.