Wikipedia:Reference desk/Archives/Science/2024 May 9

= May 9 =

LED lighting dimmer switch
Can you tell me about this? Does it it exist yet?

I now have parrot bird with red eyes and if you turn the light on from dark to light it drops him on his back. So I can't use LED bulbs in his room. Because previously I used a dimmer to bring light up gradually. Can you tell me? Thank you. Iqbal. 146.200.107.107 (talk) 02:15, 9 May 2024 (UTC)
 * Yes. They exist. I just went to the web site of my local hardware store, searched for "led dimmer switch" and found several. HiLo48 (talk) 02:25, 9 May 2024 (UTC)
 * There are also dimmable LED light bulbs that can be used with most types of dimmer. --Lambiam 06:02, 9 May 2024 (UTC)
 * There are also led light bars that can be programmed for a gradually changing brightness and colour to simulate sunrise and sunset. Some even support simulating random clouds passing in front of the sun and the occasional thunderstorm with lightning. Aquarium lights tend to have such features. PiusImpavidus (talk) 12:13, 9 May 2024 (UTC)
 * Note that dimmable LEDs don't dim the same way incandescents do.
 * When incandescents dim, a lower level of power continues to be continuously conducted through the filament. The lower power produces less light.
 * LEDs don't really have variable brightness in response to different levels of power the same way incandescents do. Instead, they're dimmed by flickering them on and off at an extremely high frequency.  The frequency is too high for our eyes/brains to perceive the flickering; but since they're not on all the time, less total light is emitted.
 * In order to respond to a decrease in power this way, the LED bulb needs to have specialized hardware in its base. So you'll have to buy special "dimmable" LED bulbs.  I've had very mixed experiences with these, fwiw, and some that are nominally dimmable don't dim well or at all.  Others produce extremely unpleasant light at lower levels.  -- Avocado (talk) 20:33, 9 May 2024 (UTC)
 * Specifically, incandescent lights (is there anyone still using those? They've been banned in the EU for over a decade) can be dimmed by reducing the root-mean-square voltage over the filament. This lowers the light output, makes it redder and lowers the efficiency. Leds have constant colour and the brightness is controlled by electronically controlling the average current. Pulse-width modulation appears to be the simplest efficient way to control the average current. Dimmable led lights have some electronics that take the input voltage as a cue to change pulse width. Flicker is invisible to humans, but may appear when there's some beating with another periodic process of similar frequency (spinning things, cameras). A simple low-pass filter would eliminate the flicker. PiusImpavidus (talk) 07:54, 10 May 2024 (UTC)
 * Yeah, you can still buy incandescents in the US. They keep partially walking back the bans.  And they're still allowed for specialty purposes (like heat lamps and candelabras), and maybe at low wattages?  I've also recently seen incandescent bulbs with purportedly higher efficiency than old ones being sold in places -- I'd be unsurprised if our regulations are weak.  And maybe leftover inventory is still allowed to be sold?  Small retailers I think get them under the table from ... somewhere.  If you search a major hardware store's site, you'll find a selection still for sale.  Here's what we've got on the topic. -- Avocado (talk) 13:17, 10 May 2024 (UTC)


 * The flicker fusion threshold of birds is much higher than humans, up to 140 Hz (see this article). So a dimmed LED light that looks merely dim to us may appear to be flickering to a bird. I can imagine that that might be as unpleasant to a bird as a flickering light is to humans. Maybe some LEDs have a phosphorescent coating that absorbs and reemits the light after a delay, thus temporally buffering the light output, which might settle the parrot. Otherwise perhaps it is better to dull the light using a translucent screen or by reflecting the light off a surface. JMCHutchinson (talk) 11:43, 10 May 2024 (UTC)
 * Yeah, even as a human (hello, fellow humans!), I find dimmed LEDs to produce a very unpleasant light. I wonder if we can detect the flickering subconsciously even if we consciously can't?  There's a theory that we can with fluorescents (which flicker even at full brightness), causing a bit of dysphoria in flourescent-lit spaces. -- Avocado (talk) 13:05, 10 May 2024 (UTC)
 * I have noticed that I can sometimes see flicker with peripheral vision that I can't when looking directly: aaand I see this is mentioned in the article. Flicker fusion threshold may also be of interest. {The poster formerly known as 87.81.230.195} 188.220.175.176 (talk) 14:57, 10 May 2024 (UTC)

Ambivert vs. omnivert
Is there a difference between ambivert and omnivert, or are these the same? 2601:646:8082:BA0:24BD:2FE2:B975:68AE (talk) 06:13, 9 May 2024 (UTC)
 * --136.54.106.120 (talk) 16:08, 9 May 2024 (UTC)
 * OK, thanks! So, an ambivert is someone who's near the middle of the scale all the time, whereas an omnivert is someone who goes from full extrovert to full introvert and everything in between? 2601:646:8082:BA0:CD56:E11E:9CF:F450 (talk) 02:45, 10 May 2024 (UTC)
 * Some researchers have questioned the validity of personality tests. I doubt that the validity of the specific labels ambivert and omnivert has been seriously studied; they may be pure pop-psych products. Also, even when valid, it can be questioned whether all this labeling isn't more harmful than beneficial. --Lambiam 08:29, 10 May 2024 (UTC)
 * I hope you're not also questioning the validity of the labels extrovert and introvert, are you??? And if these are valid terms (which they are), then we also need a term for someone who's in the middle of the scale! 2601:646:8082:BA0:448D:8CB2:2FBC:B6C7 (talk) 23:19, 10 May 2024 (UTC)
 * Do we also need a term to label people who are halfway between introvert and omnivert? One problem with these personality tests is that they do not depend on a person's actual behaviour, but on their self-reported interpretation of their self-imagined behaviour in hypothetical, vaguely described situations. Validity as a personality label requires IMO consistent reproducibility over time, not of such self-reports, but of actual behaviour in a context of actual situations . I don't expect this stuff will be able to hold itself up well against the scientific method. --Lambiam 06:34, 12 May 2024 (UTC)
 * Did you not read any part of this section other than your own comments??? First of all, as already explained above, the definition of omnivert is not that of someone occupying a certain position on the scale, but someone who fluctuates between extroversion and introversion, and hence there can be no "halfway" between omnivert and anything else!  And as for the others, yes we do need specific terms for the far ends of the scale and also for the middle -- this is standard for any property which exists along a continuum!  Also, I've personally taken both the ocean test and the MBTI test, and I can tell you, the situations described in the current versions are quite specific and mostly applicable to real life (at the very least, with the disclaimer that I'm one of the most pronounced introverts ever, I had no problems with the questions being "vague" or not applicable to me personally), so your criticism of these tests (at least in their current versions) is completely misplaced!  And, as far as your demands for observation of "actual behaviour" (your emphasis, not mine), this would require a Big Brother-style system of constant and pervasive surveillance of your test subjects, which is completely impractical, highly illegal and unethical, and would itself introduce bias into your observations should your test subjects become aware of it (due to them modifying their own behavior to conform to perceived social norms out of fear of judgment) -- so, the stuff you propose wouldn't be able to hold itself up against the scientific method either (not to mention that it would most likely be disallowed on legal and ethical grounds)! 2601:646:8082:BA0:C178:97BE:AF93:9928 (talk) 09:41, 12 May 2024 (UTC)
 * You yourself wrote, "we also need a term for someone who's in the middle of the scale", i.e., between "the labels extrovert and introvert". This is what the term ambivert purports to signify. I responded to the claim of this need, wondering why there should be a need to label the extremes and one point in the middle, but not other points on the scale? --Lambiam 20:12, 14 May 2024 (UTC)
 * Because then all of the other points on the scale can be visualized and described in relation to these 3 points -- whereas if only the two extremes were labeled, then it would not adequately describe those who are close to the middle! 2601:646:8082:BA0:BC05:6EA8:F933:9E6D (talk) 11:07, 15 May 2024 (UTC)
 * Not if they agree to it first, IP-hopper. As to this "omnivert" notion, it could be called "situational". Many people are more comfortable in certain settings than in other settings. That's "normal". ←Baseball Bugs What's up, Doc? carrots→ 14:49, 12 May 2024 (UTC)
 * Maybe if they give fully informed consent it might be legal, but then you run into the other problem I mentioned (which you conveniently ignored) -- if they know they're being watched, they won't act like their normal selves (and the more you watch them, the more they'll put their guard up), so you won't see their "actual behaviour" in "actual situations", and you'll get skewed results! 2601:646:8082:BA0:28E6:4E7D:4BB4:DD49 (talk) 20:01, 12 May 2024 (UTC)
 * That would be tragic. ←Baseball Bugs What's up, Doc? carrots→ 23:51, 12 May 2024 (UTC)
 * That is just how people work -- and that is the reason why self-reporting of actual behavior is the best you can get in terms of data! 2601:646:8082:BA0:692F:1147:32D5:BCAA (talk) 01:54, 13 May 2024 (UTC)
 * Cultural anthropologists study actual behaviour. They don't go around handing out questionnaires. --Lambiam 07:03, 15 May 2024 (UTC)
 * This is in the realm of psychology, though, not anthropology (cultural or otherwise) -- which brings up yet a third problem with your proposed methodology, that merely observing the behavior of your test subjects will not reveal what's going on inside their head at the time, and thereby also give you inaccurate results! (For example, an introvert like me might be forced against his/her will to attend an office party and even to mingle with other people thereat (and even to feign cheerfulness while doing so), which your methodology will register as extroverted behavior and will simply not see how miserable it makes him/her -- or, just to cover both sides, an extrovert might be forced to spend time working or studying alone, which your methodology will register as introverted behavior and not see how much he/she hates it!)  And you still haven't answered how you would counter the observer effect (which, in this scenario, would manifest itself on a very macroscopic scale due to the fact that, as I already said, many people simply won't act like their own natural selves when they know they're being watched all the time)! 2601:646:8082:BA0:BC05:6EA8:F933:9E6D (talk) 11:07, 15 May 2024 (UTC)
 * And also, I see a fourth problem with this kind of methodology, and that has to do with sample selection bias -- introverts are far less likely to volunteer for an experiment in which their actual behavior would be monitored, especially if this includes being monitored inside their own homes, and the more introverted a person is the more likely he/she would refuse to take part in such an experiment (as an introvert from the deepest end of the scale, I personally know I would refuse without thinking twice), so you'll get a sample which is skewed toward extroversion, and that would also give you inaccurate or incomplete results! (This, indeed, is one area in which the current methodology of anonymous self-reported personality tests with hypothetical questions about various social situations is superior to any other suggested here -- there is something inherently reassuring about knowing that only me and the machine see the actual personal responses, especially for an introvert like me -- and this makes it better in terms of reducing sample bias than even self-reporting of actual behavior, because the latter cannot easily be reduced to a machine-processable series of multiple-choice questions and would require short-answer questions to be interpreted by a human psychologist, and knowing that an actual human sees your individual responses and your identifying data is much harder to swallow, especially given that being judged by a psychologist might (sometimes) have real-world consequences!) 2601:646:8082:BA0:2D37:9C1D:9DB2:251E (talk) 13:36, 17 May 2024 (UTC)