Talk:Human skin color/Archives/2020/October

Skin pigmentation

skin pigmentation is a disease that makes you an albino, albinos are black and white. — Preceding unsigned comment added by 68.148.190.160 (talk) 00:58, 7 October 2020 (UTC)

Description regarding differences in skin among individuals

Epl, regarding this? Exactly what is it you are aiming for?

No, not everyone's skin color is due to "effects [of] recent exposure to sun." Albinism is an extreme example of that. Many people are pretty much the same color they were all their lives, which is especially true for those sensitive to the sun. And "recent" is inaccurate since sun exposure having affected a person's skin color need not be recent. If you are going to WP:Edit war over this, I'll simply source it. Flyer22 Frozen (talk) 03:47, 18 October 2020 (UTC)

Tanning is the result of recent exposure to the sun. Exposure more than several months old does not affect skin color. If an individual has no exposure for an extended period, that individual will show no tan.

As was indicated correctly by the revision preceding mine, two factors affect the color of human skin, those being genetic makeup and tanning. Even though some individuals cannot tan, or are not showing a tan at some particular time, tanning remains one of the factors that affect human skin color. The purpose of the statement is to identify the factors that may affect human skin color, not to assert that all individuals at all times show a tan. — Preceding unsigned comment added by Epl (talk • contribs) 04:13, 18 October 2020 (UTC)

You stated, "Tanning is the result of recent exposure to the sun. Exposure more than several months old does not affect skin color." Are you forgetting that many people of color started out lighter than they were (some significantly lighter than they were) and are darker now only due to exposure to the sun, which happened years ago for them? That is not recent. It's not tanning in the sense of being temporary and returning to one's previous skin color. Many white people are also darker today because of sun exposure from years ago. Again, not recent. So I fail to see what point you are making. Your wording makes it seem that it's never an "or" matter. But it clearly is. My point is that not everyone is the color they are solely due to genetics or necessarily due to genetics and exposure to the sun.

I'll alert one or more WikiProjects tagged at the top of this talk page to this discussion. Flyer22 Frozen (talk) 04:42, 18 October 2020 (UTC) Tweaked post. Flyer22 Frozen (talk) 04:46, 18 October 2020 (UTC)

The premise of the article is that two factors affect skin color for humans, those being genetics and tanning. Tanning is known to have a temporary affect. If you wish to add that tanning rather has a permanent affect, or that a third factor affects skin color, then you would need to supply a reference supporting such claims. The "point" of the statement is that the color of skin of a human individual is determined by a combination of two factors. The first is genetic makeup. The second is exposure to the sun. Other factors one might imagine, for example, how much chocolate ice cream someone ate in the past month, or someone's height, do not affect the color of human skin. The wording does not imply anything other than that genes and tanning are in the category of all factors that may affect the skin color of a human, and that everything else, including ice cream and height, are not in that category. Epl (talk) 05:11, 18 October 2020 (UTC)

You are using tanning to mean "a temporary effect." The article is not using it to mean that. Not solely anyway. But because the term tanning is often used to refer to deliberate and temporary darkening of the skin...while it is well known that the skin turning darker due to sun exposure is often not temporary, your edit is inaccurate. Again, your "combination of two factors" piece is misleading because it makes it seem that one has the skin color they have due to both genetics and temporary exposure to the sun. When it comes to why someone has the skin color they have, I agree that the first factor is genetic makeup and that the second factor is exposure to the sun. What I don't agree with is making it seem that people always, or even most of the time, have the skin color they have due to both. Per my previous commentary above, that is not always the case, especially if thinking of tanning in a temporary context. The article likely needs some tweaking with regard to how the term tanning is being used.

As for references? I already indicated a willingness to source what I state. Your condescending "Other factors one might imagine, for example, how much chocolate ice cream someone ate in the past month, or someone's height, do not affect the color of human skin" comment is cute but completely unnecessary. I will come back to this section significantly later in the day with academic sources. And I suggest you supply academic sources in this section for your "always a combination" position. Flyer22 Frozen (talk) 06:25, 18 October 2020 (UTC)

Genetics and tanning are absolutely not "the" two factors that affect human skin colour. Just off the top of my head, there's accumulation of beta-carotene due to diet; changes to peripheral circulation due to temperature, emotion, or circulatory system disorders; accumulation of bilirubin due to liver dysfunction; cyanosis; artificial colouration by tattoos and suchlike; and probably many other things I'm forgetting. My physiology textbook says the two factors that determine human skin colour are "pigments" and "blood". Sun exposure, beta-carotene, bilirubin, artificial colouration and genetics can contribute to the former, while changes to peripheral circulation, cyanosis and genetics can contribute to the latter. Adrian J. Hunter^{(talk•contribs)} 08:10, 18 October 2020 (UTC)

If you wish to improve the accuracy of the claims in the article, based on references to credible sources, then I of course have no objection, as long as the strength of the revised claims are proportionate to the reliability of the sources. I am not specifically promoting any fact-based view, only revising the earlier language.

I will make a final effort to clarify why the language is not likely to mislead as you seem to worry it may. Imagine making a list of all the attributes that describe an individual person. It would be a long list. How wealthy is someone? What was the mother's age when someone was born. What is someone's favorite food? How many siblings does someone have? Almost anything we can imagine about a person has no possibility to determine skin color. Recent exposure to sun is not in the category of attributes that have no possibility to determine sun color. Therefore, it is the complementary category, of attributes that have the possibility to determine skin color. Whether everyone at all times is showing a tan is not considered under the claim, only that recent exposure to sun is excluded from the long list of factors that have no possibility of affecting human skin color, and rather is included in the short list a factors that do so. Recent exposure to sun is one of the factors that affects human skin color, whether or not every single human has experienced a change in color due to recent exposure to sun.

By analogy, one might indicate that whether someone is diabetic and which foods someone has recently eaten both determine current levels of blood sugar. Never is it implied that everyone is diabetic, only that the diabetic individual is likely to have higher levels of blood sugar, compared against others, following consumption of food high in sugar. Epl (talk) 16:13, 18 October 2020 (UTC)

Late reply. If you are going to state "genetics and recent sun exposure" (rather than "genetics or recent, or long-term, sun exposure") and leave it at that, it is misleading per what I argued above, including the fact that skin color is also due to long-term (not just recent or temporary) exposure to the sun.

Looking at academic sources on this topic:

This 2010 "Human Evolutionary Biology" source, from Cambridge University Press, page 205, states, "Our understanding of human skin color genetics is still incomplete, but comparative genomics is now providing evidence that skin color is a polygenetic trait controlled by several genes that interact in complex ways. Skin, hair, and eye color are all affected by multiple genes, and their pleiotropic interactions. In some populations some variant forms of the genes account for more of the variation in skin color rather than in hair color and vice versa. Combinations of different forms of the genes have brought about the complex and continuous variation in skin coloration that we see in modern humans." I don't think that the source is making a polygenism argument.

This 2011 "Andrew's Diseases of the Skin E-Book: Clinical Dermatology" source, from Elsevier Health Sciences, page 24, states, "After UV exposure, skin pigment undergoes two changes: immediate pigment darkening (IPD, Meirowsky phenomenon) and delayed melanogenesis. IPD is maximal within hours after sun exposure and results from metabolic changes and redistribution of the melanin already in the skin. It occurs after exposure to long-wave UVB, VA, and visible light. With large doses of UVA, the initial darkening is prolonged and may blend into the delayed melanogenesis." Going by this source, you wanting to stress "recent" is understandable. But one of my points, which I've noted more than once now, is that a person's skin color may be due to prolonged sun exposure, not just recent sun exposure. And if you think that readers aren't going to take "recent" to exclude long-term sun exposure, you should think again. Even with common sense telling them that long-term sun exposure plays a factor, stating "recent" only and "and" (instead of "or") is misleading. And if one wants to argue that people typically receive long-term sun exposure because of the years they've been alive and so just about everyone has had long-term sun exposure, I must note, that like this 2013 "Pediatric Dermatology E-Book" source, from Elsevier Health Sciences, page 194, reports, "the majority of most individuals' lifetime exposure occurs during childhood and young adult life." Sources, including this one, stress long-term exposure to the sunlight when speaking of things like cancer. Just about everyone would have the same risk of cancer if "long-term exposure to the sunlight" simply meant the amount of sun exposure that just about everyone has had. But, no, sources use things like "long-term exposure to the sunlight" to stress those who are more at risk than others...such as those who regularly engage in tanning practices. Some sources state "chronic exposure to UVR" to indicate things such as that.

This 2013 (reprint) "Fundamentals of Applied Pathophysiology: An Essential Guide for Nursing and Healthcare Students" source, from John Wiley & Sons, notes, for example, that those with Type V skin have "naturally brown skin with dark hair and brown eyes. These people burn only with prolonged exposure to the sun and their skin further darkens easily."

This 2015 "Anatomy and Physiology - E-Book" source, from Elsevier Health Sciences, page 189, states, "[...] Heredity determines how dark or light one's skin color will be (see Chapter 48). Other factors can influence the expression of the genes for melanin production. Sunlight is an obvious example. Prolonged exposure to the ultraviolet (UV) radiation in sunlight causes melanocytes to increase melanin production and darken skin color (Figure 10-10)." Like Adrian J. Hunter, the source goes on to note other factors that contribute to skin color, stating, for instance, that "other pigments such as the yellow pigment beta-carotene (B-carotene) found in many vegetables and roots (for example, carrots) also contribute to skin color." And, for the record, when I stated above that "I agree that the first factor is genetic makeup and that the second factor is exposure to the sun.", I was referring to the primary factors. These two things are what sources primarily focus on regarding skin color, which is currently reflected in the article.

Looking at these and other academic sources, I'm thinking we can do better relaying the reasons for different human skin colors in the lead. Flyer22 Frozen (talk) 22:56, 19 October 2020 (UTC)

There are plenty of possibilities for improving the accuracy of the opening passage. Go at it if you wish.

Thank you for citing the sources, but I notice no difference in your versus my accounting of the scientific facts, which as I have stated, is a subject on which I have no particular view other than that expressed by the version of the article to which my revisions were applied.

However, note (again) that the revised language only indicates that sun exposure is among the factors that have the potential to affect the color of an individual's skin, not that every human individual is currently affected as such. (Smoking is a factor that affects human life span, a comment not negated by some individuals having no habit of smoking, or even by some having never smoked even once. Value of real estate holdings is factor that effects the net worth of an individual or organization, a comment not negated by some having no holdings.)

Use of the term "recent" does not contradict any comment you have made. The term simply indicates that the farther in the past some exposure to the sun has occurred, the less likely it is to have any effect currently observable. It does not imply any particular time duration. The term "prolonged" also does not imply any particular time duration. The uses are vague with respect to any particular amount of time, and the two terms are not in conflict. Also notice that at least in some of the uses, "prolonged" is describing the time duration of exposure, not the time duration of the effects of exposure, which is a different event. An argument that "recent" is a misleading term would require two premises: 1) "Recent" implies a time duration below some value. 2) Skin color may be affected by events farther back in time than that value. Neither premise appears in your analysis.

To summarize, the choice of language to include "recent" simply indicates color changes due to any single event of sun exposure are transient not chronic.

Also note that cancer risk occurs from accumulated damage to the skin, but is not associated (as far as I know or you seem to have sourced) with skin color. That either cancer risk or skin color might be associated with the term "prolonged" to describe exposure is irrelevant, because the precise set of concepts and relations associated with any use of the term may naturally vary according to context. Epl (talk) 22:00, 20 October 2020 (UTC)

I see no need to debate this any further. We disagree. Per what I've stated above and the sources I listed above, I do not agree with your wording. And it's clear that Adrian J. Hunter doesn't either. But then again, Adrian J. Hunter also doesn't agree with the current wording. And I already stated that "Looking at these and other academic sources, I'm thinking we can do better relaying the reasons for different human skin colors in the lead." You are stating all these things while providing no sources to support what you are stating. Your argument that "The term 'prolonged' also does not imply any particular time duration." is not entirely accurate. This is especially when sources on the topic mention a time frame. Of course, they typically are not exact by stating something like "four years of exposure." But it's usually clear that unless referring to sunburn, they don't mean "for a day" or some other short time. You argued "that skin color might be associated with the term 'prolonged' to describe exposure is irrelevant, because the precise set of concepts and relations associated with any use of the term may naturally vary according to context", but I don't see how one can't then argue the same for "recent." And the issue I have with your wording is not simply with the word "recent."

Two editors (three if counting TSamuel who thanked me for reverting you via WP:Echo) thus far are against the wording you used; so per WP:ONUS, you should not restore that. Flyer22 Frozen (talk) 03:09, 21 October 2020 (UTC)

If my suggestion has been rejected, I still would push strongly for language different from that currently used. It is a rather awkward and generally problematic structure, "Differences in skin color among individuals is caused by variation in pigmentation, which is the result of genetics (inherited from one's biological parents), the exposure to the sun, or both." It seems to suggest editorial uncertainty about why different human beings have different colors. In fact, this language is frankly generally showing poor style according to a variety of considerations.

(Also note the lack of grammatical agreement between "Differences" and "is". This discrepancy is an error, which I myself originally introduced.)

(And please take a final procedural note, that you might refrain from indicating that you see no value in arguing a point immediately before continuing to argue that point. The objections evince a misunderstanding of the fundamental logical concepts as expressed through the language. I accept that you have a different view, but if you prefer that I no longer defend my position, then please don't conclude the discussion with a straw man attack.) Epl (talk) 03:49, 21 October 2020 (UTC)

Stating "I see no need to debate this any further." at the beginning or end of my post makes no difference. I led with that in a topic sentence way, explaining why I felt/feel that way. There was no straw man attack. I need no lessons from you on anything. In the future, you might want to hold yourself back from making condescending comments, especially when you are arguing matters while providing no sources for your arguments.

What we agree on right now is re-wording the text, but not exactly for the same reasons. Flyer22 Frozen (talk) 19:13, 22 October 2020 (UTC)

Nothing written was intended as a slight against you, so I'm sorry that anything rubbed you the wrong way. I had noticed your objection to the "ice cream" example, which was simply a rhetorical device, and makes no reference to you personally in any way. The purpose of the example was to draw a contrast between one category of items, such as ice cream, which may have no effect on skin color, versus other items, such as sun exposure, which may have such an effect. The device depends on an assumption that all would agree that ice cream is in the former category, and is not a suggestion that you would think otherwise. Neither is the characterization of your comments as "straw man" an insult, just an observation that you appeared to get from my comments something different from what I intended to put in them.

And again, since my proposed revisions targeted language not facts, I would not understand why you would want me to support them with references, or even how I might do so. Epl (talk) 21:52, 22 October 2020 (UTC)

You've made claims about what factors cause/contribute to skin color and claims about wording regarding this topic. Given what I've argued above, I fail to see why you think I wouldn't expect sources from you on a few of your arguments. But I don't want to debate this now as well. Flyer22 Frozen (talk) 23:12, 22 October 2020 (UTC)