Blog: Science

Most of these posts were originally posted somewhere else and link to the originals. While this blog is not set up for comments, the original locations generally are, and I welcome comments there. Sorry for the inconvenience.

Avian socializing in the 21st century

How nifty!

Parrots are social creatures. However, most pet parrots are singletons. They get lonely and sometimes that leads to destructive behavior.

From the Smithsonian:

Once the birds had learned how to initiate video interactions, the second phase of the experiment could begin. In this “open call” period, the 15 participating birds could make calls freely; they also got to choose which bird to dial up. Over the next two months, pet parrots made 147 deliberate video calls to other birds. [...]

For starters, they found that the parrots took advantage of the opportunity to call one another, and they typically stayed on the call for the maximum time allowed during the experiment. They also seemed to understand that another live bird was on the other side of the screen, not a recorded bird, researchers say. Some of the parrots learned new skills from their virtual companions, including flying, foraging and how to make new sounds. [...]

The birds forged strong friendships, which researchers measured by how frequently they chose to call the same individual. Parrots who initiated the highest number of video calls also received the most calls, which suggests a “reciprocal dynamic similar to human socialization,” per the statement.

The article links to this ACM paper. Yes, ACM-CHI, meaning it's from a technical conference not an animal-behavior conference. (Also, I guess this stretches the boundaries of the 'H' in CHI, which stands for Computer-Human Interaction, or at least did the last time I attended that conference.)

TIL: ophthalmology edition

I started getting noticeable floaters something like 8-9 years ago. (I see I failed to record it at the time, so I'm estimating now.) Floaters are bits of stuff in the vitreous in your eye that, as the name implies, float around and sometimes get in your way. They don't go away. They were quite annoying at first, but over time they became less invasive -- presumably my brain was learning to ignore them for the most part. I'd still see hem but they didn't get in the way as much.

A few weeks ago I noticed/realized that I've been having more trouble reading lately, whether sitting at a computer or reading a book. It wasn't a sudden change -- not the sudden onslaught that sends one for a same-day appointment to check for retinal detachment. I think it's been building for a while and finally crossed some critical threshold. I couldn't quite tell if the problem was obstruction (what floaters do) or acuity, but I'm not generally having acuity problems.

I had a checkup scheduled for earlier this week anyway, so I asked my ophthalmologist to take a look. She said yup, sure are a lot of floaters and stuff in there. I asked if she could compare what she's seeing now to the last photo she took of the inside of my eye, but that photo didn't help much. She sent me to a retina specialist just to be safe.

I saw that specialist this morning and learned some new things. Read more…

Today I learned (veterinary edition)

Orlando saw an ophthalmologist today because his pupils barely contract and my vet wanted a consultation. He's been somewhat like that since I adopted him six years ago (I've never seen pupil slits), but it's become more pronounced recently. Google had told me that this can be an age thing and it can indicate hypertension. We checked his blood pressure recently to evaluate the latter and got ambiguous results; my vet also says that measuring feline blood pressure is kind of dicey. (They took three readings in one visit, and one of them was not like the other two.)

Things I learned today:

  • Orlando is almost certainly older than we thought he was. We thought 10ish and are now bumping that up to 12ish.

  • Iris atrophy is a thing that happens in older cats where the relevant muscles just don't work as well any more. I wonder if that happens in humans too -- never heard of it before. (The ophthalmologist didn't find anything else wrong, though didn't rule out hypertension and suggested rechecking blood pressure, so this is the working theory. His optic nerve and retinas look fine.)

  • They use the same numbing drops on cats that they do on people, complete with orange dye -- which apparently makes (something) easier to see, but I've failed to retain what the (something) is.

  • Orlando's ocular pressure is the same as mine was at my ophthalmologist visit on Friday. But mine's the result of glaucoma drugs and his comes naturally. So, no worries there.

  • He has a tiny cataract forming in one eye -- something to check back on later, but nothing to do now. I giggled at the mental image of Orlando wearing glasses.

TIL: equinox, kind of

Yesterday was the equinox, but I couldn't help noticing that sunrise was at 7:07AM and sunset was at 7:16PM. That stretches the definition of "equi" a bit. Looking ahead, the day won't be within a minute of 12 hours until September 25 or 26. (One's a minute longer, one's a minute shorter.) So off to Google I went.

There are two things going on, it turns out. The first is that the equinox is relative to the center of the sun, but we count sunrise and sunset from when the top is visible. But that only accounts for 2.5-3 minutes at my latitude.

The bigger factor is atmospheric refraction: after the sun has actually set (all parts past the horizon), or the reverse in the morning, you can still see the sun. What? Yeah, apparently you can look westward at sunset and see "the sun" even though the sun is not in your line of sight; light bends. This effect varies with atmospheric conditions, but is usually good for about six extra minutes of day.

I said that I won't see a 12-hour day here for a few more days. Apparently that effect gets stronger as you move toward the equator; this site says at 5 degrees North that date isn't until October 17. It also says the day is never exactly 12 hours at the equator, when I thought the equator was the one place where you had reliable 12-hour days all year. Today I learned.

I wonder -- because I'm the sort of person who wonders about stuff like this -- what the effect is in halacha, Jewish law. The day starts at sunset, but when beginning Shabbat we add some extra time just to be safe -- 18 minutes in most communities. That's l'hatchila, what you should do from the outset, but b'dieved, after the fact, if you cut into the 18 minutes with your preparations, it's ok because it's not actually sunset yet. Except... maybe it is? If you have a bad week and light candles two minutes before (nominal) sunset -- when you can still see the sun in the sky, except it's not there -- have you kindled fire on Shabbat? Or do you go by what you can see anyway? I plan to ask this on Mi Yodeya if it's not already there, but first I have to finish Sukkot preparations.

I later asked on Mi Yodeya but didn't get an answer. Much later, I asked on Codidact.

What would be different if humans had broader visual spectrum?

Somebody on Worldbuilding (about developing fictional worlds) asked how having a broader range of vision, into the infrared and ultraviolet, would affect what people see. Having a tiny bit of relevant personal experience, I answered: Read more…

Is Wikipedia trustworthy?

A student posted a question on the SE site for writing. Paraphrasing: I was taught not to use Wikipedia for research because anybody can post anything, so I've been using a reputable published encyclopedia instead. But isn't stuff on Wikipedia reviewed? Is it trustworthy?

I answered:

Wikipedia is a crowd-sourced site where anybody can contribute, like Stack Exchange. Wikipedia strives for verifiability and neutrality and has an active user community, but that doesn't mean that things can't get past it. It doesn't mean information there can't be wrong. Some pages are full of detailed, reliable information; some are not. So, in evaluating the reliability of what you read on any given page there -- or anywhere else! -- you need to ask yourself how they know what they say.

Do they cite sources? Good Wikipedia pages do. Do they not cite sources but make a logical argument? (Not so common on Wikipedia, but common elsewhere on the Internet.) Do they present evidence?

Since you asked about Wikipedia I'll focus on sources. For a first approximation, ask yourself if the sources cited are generally considered to be credible. If they cite peer-reviewed, publicly-available research, that's pretty good. If they cite the National Enquirer (a tabloid full of sensationalist fiction masquerading as news), be very suspicious. If the facts you're checking are particularly important, central to your thesis for example, then you might need to actually go look up some of those sources to confirm that the Wikipedia page accurately represents them. If the facts are less important or tangential, or your assignment doesn't call for this degree of rigor, then establishing that Wikipedia's sources are credible might suffice without looking them up.

I wrote more about evaluating sources in this answer, drawing in part from this article from UC Berkeley.

For Wikipedia in particular, you can also check the "talk" page associated with the topic you're looking at. The "talk" pages can sometimes tell you if any content is disputed or of questionable quality. If the "talk" page is empty, though, don't assume that means everything's fine -- it might mean that no experts have looked at the topic yet.

It's impossible to say, globally, "Wikipedia is trustworthy" or "Wikipedia is not trustworthy". Unlike an edited, curated encyclopedia, it contains material at a range of quality levels. I find Wikipedia to be a good starting point in research; sometimes I find everything I need there (including supporting sources), and sometimes I don't. Don't rule it out, but do be prepared to go beyond it.

Gathering information online (evaluating sources)

A student asked on the SE site for writing about how to do online research, and specifically how to evaluate the information returnred by Google. This is the answer I posted:

In doing research, whether online or offline, there are two types of assertions you can encounter: supported and unsupported. (Just like on Stack Exchange!)

An unsupported claim isn't worth very much. Some blog post says "X", but somewhere out there is another blog post saying "not X". This happens at sites that look more credible than blogs, too. And some of them might sound credible, until you realize that the author has a vested interest or the post is 7 years old and things have changed.

This is why Wikipedia, for example, bars original research and demands citations. When you come across a (well-written) Wikipedia page, or some other source like it, you'll see a bunch of citations at the bottom. Those citations explain where they got their information.

Don't just say "there are citations; done!", though. Citations can be misunderstood or misrepresented, particularly in works that aren't carefully reviewed. You have more work ahead of you.

If you need to verify a claim, find its citation and then go look at that source. If it has what you need, great. If not and it has citations, follow those. Iterate until you find what you need or you reach a dead end on all threads.

When evaluating a source, look for these key factors, taken from this quick guide to evaluating a source's credibility from UC Berkeley:

  1. Authority - Who is the author? What is their point of view?
  2. Purpose - Why was the source created? Who is the intended audience?
  3. Publication & format - Where was it published? In what medium?
  4. Relevance - How is it relevant to your research? What is its scope?
  5. Date of publication - When was it written? Has it been updated?
  6. Documentation - Did they cite their sources? Who did they cite?

In this answer I've talked mostly about #6, but everything on that list is important.

Investigating sources is a standard tool of academic researchers, reference librarians, and (good) journalists, among others. If you don't have access to an academic researcher or a journalist to learn the technique from, make friends with the reference librarian at your local library. That person will be able to help you decipher references, hunt down obscure sources, and so on.

You might find these resources collected by Tulsa Community College about evaluating sources helpful. (Many universities have such guides for their students; that's just the first one I found.)

Astronomical puzzle

Unless you're on the equator, neither the earliest sunset nor the latest sunrise of the year is on the winter equinox (source). In Pittsburgh, the earliest sunset is usually around December 9 or 10. People who keep Shabbat tend to notice this.

This happens because apparent solar time doesn't line up exactly with mean solar time. The day isn't consistently (or exactly) 24 hours long, and "noon" usually isn't exactly 12:00. Plus there's some shift because of latitude. Fine.

I wondered why there wasn't a corresponding effect at the summer solstice, and played around with this slider to map it out. There actually is an effect, but it's much smaller -- the earliest sunrise was parked at the same time (rounded to the minute) from June 10-19, and the latest sunset is parked at the same time from June 23 - July 1. So in the week or so surrounding the solstice there's barely any change, while in December the boundaries more more visibly. The latest sunset is June 23 which is barely past the solstice, but it's also July 1 (and every day in between of course). And the earliest sunrise is only a couple days before, but also a week before. So what I notice is "earliest sunrise June 19, latest sunset June 23", even though those bands are wider. In the winter, on the other hand, sunset has been creeping later for a week and a half when you get to the solstice.

I guess this, too, is because of latitude, but it's still not intuitive to me. I wonder what's still wrong with my mental modeling.

Purim science?

One machine-learning technique is to pit evolving neural networks against each other in cage matches and then learn from the results. This is called Generative Adversarial Networks (GANs).

At yesterday's Purim festivities somebody described the following cutting-edge research, and I remembered just enough keywords to be able to find the paper later:

Stopping GAN Violence: Generative Unadversarial Networks Samuel Albanie, Sébastien Ehrhardt, João F. Henriques While the costs of human violence have attracted a great deal of attention from the research community, the effects of the network-on-network (NoN) violence popularised by Generative Adversarial Networks have yet to be addressed. In this work, we quantify the financial, social, spiritual, cultural, grammatical and dermatological impact of this aggression and address the issue by proposing a more peaceful approach which we term Generative Unadversarial Networks (GUNs). Under this framework, we simultaneously train two models: a generator G that does its best to capture whichever data distribution it feels it can manage, and a motivator M that helps G to achieve its dream. Fighting is strictly verboten and both models evolve by learning to respect their differences. The framework is both theoretically and electrically grounded in game theory, and can be viewed as a winner-shares-all two-player game in which both players work as a team to achieve the best score. Experiments show that by working in harmony, the proposed model is able to claim both the moral and log-likelihood high ground. Our work builds on a rich history of carefully argued position-papers, published as anonymous YouTube comments, which prove that the optimal solution to NoN violence is more GUNs.

I haven't read the full paper yet, but on a quick skim it does not disappoint. More info.

I'm delighted to see that the paper was submitted to SIGBOVIK 2017. I had no idea that Dr. Bovik had his own SIG.

ETA: Not only was that paper submitted to SIGBOVIK, but SIGBOVIK is a real thing. How did I not know about this gem from my alma mater? (Sadly, this year's conference starts at 5PM on a Friday, which would be challenging. Maybe I'll have better luck next year.)

Psychological effects of teleportation

Somebody asked about the psychological effects of instantaneous teleportation like in Star Trek. If your location changed drastically and instantaneously, would you experience cognitive dissonance? How might one mitigate negative effects?

I answered: Read more…