Why do the dots disappear?

September 2, 2014 • 8:10 am
This is one of the most baffling illusions I’ve ever seen. Take a look at the gif below.  First, look at any yellow dot as the figure moves. The yellow dot remains present and stationary. If you concentrate on all three yellow dots, they remain there as well.
But now concentrate on the central green dot. You will see one or more of the yellow dots disappearing and then reappearing sporadically. They are not—this is an optical illusion. The dots remain and your brain simply doesn’t register their presence from time to time. Weird, eh?

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An article by John Whitfield in Nature News, “A brain in doubt leaves it out,” explains the phenomenon:

Yoram Bonneh, of the Smith-Kettlewell Eye Research Institute in San Francisco, and colleagues have been showing people a swirling pattern of blue dots superimposed on some stationary yellow dots1. [JAC: for some reason the reference isn’t given.]

The yellow dots seem to wink in and out. But the erasing happens in the mind, not the computer. Nearly everyone tested saw the effect.

The brain seems to have internal theories about what the world is like. It then uses sensory input – which tends to be patchy and disorganized – to choose between these. In some sensory situations, different theories come into conflict, sending our perceptions awry.

The illusion, which Bonneh’s team calls motion-induced blindness, catches the brain ignoring or discarding information. This may be one of the brain’s useful tricks, a deficiency – or perhaps both, says Bonneh.

The researchers suggest this may (and I suggest that it certainly must) happen in daily life:

The researchers speculate that this phenomenon could happen in everyday life without us noticing it. A highway at night, with drivers staring dully at a mass of moving lights, might recreate the kind of conditions used in the experiments, says Bonneh, causing objects – the tail lamp of the car in the next lane, for example – to temporarily vanish.

Jack Pettigrew, a neuroscientist at the University of Queensland in Brisbane, believes that the illusion results from a tussle for supremacy between the left and right halves of the brain.

He has found that applying a pulse of magnetism to the brain to temporarily disrupt its function affects the occurrence of motion-induced blindness. When the pulse is applied to the right hemisphere (leaving the left dominant) the dots disappear; zapping the left brings them back2.

The left hemisphere seems to suppress sensory information that conflicts with its idea of what the world should be like; the right sees the world how it really is. Some people with paralysis caused by injuries to their right hemisphere will deny that they are disabled.

My only question is why it takes motion to generate this illusion. Is that because motion is associated with visual confusion?

Source of gif: Professor Michael Bach at the University of Freiburg, via reader Grania. Bach has a page with 113 of these damn things!

 

Readers’ wildlife photos

September 2, 2014 • 5:36 am

Reader Bruce Lyon, whose photos from China appeared not long ago, has sent us some more:

Here are few more bird photos from my June trip to China. I visited Kuankuoshui (KKS) Nature Reserve, where two Chinese colleagues study interspecific brood parasitism in cuckoos. The cuckoos are obligate brood parasites that never have their own nests but instead lay eggs in the nests of individuals other species, who then raise the eggs and chicks. KKS is remarkable site because a whopping 11 species of parasitic cuckoos c0-occur there (a few of the species are rare). I saw 5 cuckoo species during my visit, including watching a parasitic egg-laying visit by a female Himalayan Cuckoo parasitizing a warbler nest. The cuckoos are tough to see, let alone photograph, and I was only able to get photos of two species: the Asian Emerald Cuckoo and the Common Cuckoo.

Below: A male Asian Emerald Cuckoo (Chrysococcyx maculatus). KKS is a famous reserve in China for the likelihood of seeing an Emerald Cuckoo. During my visit there was a steady stream of Chinese birders and photographers seeking this species.

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Below: Another photo of the same male:

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Below: Emerald Cuckoos parasitize only a couple of warbler species at KKS, including this Green-crowned Warbler (Seicercus burkii). The warblers nest along cutbanks along roads and my colleagues have observed female cuckoos carefully searching the same cutbanks to find warbler nests to parasitize.

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Below: Another Emerald Cuckoo host, the Buff-throated Warbler (Phylloscopus subaffinis) with a grub to feed a fledgling. This species nests in a completely different habitat, bushes in open areas. This would require different search methods and perhaps search images by the female Emerald Cuckoos.

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Below: A female Common Cuckoo (Cuculus canorus) perched high in a tree. The fog was so dense that it was difficult to focus on the bird let alone photograph it. Cuckoos often perch high in trees where they scope out their surroundings and find host nests, presumably by watching birds building their nests or making trips to and from their nests. At the species level the Common Cuckoo is a host generalist that uses lots of different host species, but individual females may specialize on a few or even a single host species.

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Below: Three species of redstarts at KKS are known to be hosts of the Common Cuckoo, including this Daurian Redstart (Phoenicurus auroreus) which associates closely with people and nests in buildings. This bird is a male.

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Below: Plumbeous Water Redstarts (Rhyacornis fuliginosus) have also been documented as hosts of Common Cuckoos. This is a water-loving species and I found its lovely habitat along gorgeous streams or lake edges.  This is a male. Like many birds that associate closely with running water, these birds wag their tails constantly, as can be seen by the blurred tail in the photo.

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Here’s a video of one I found on YouTube; the notes say, “This small bird was found to be jumping / hovering / and fishing at the base of Ban Jhakri Water Falls near Peeling in West Sikkim. Its act of occasionally widening of its red tail is worth watching.”

 Below: Plumbeous Water Redstart habitat—a lovely stream through the forest.

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For pictures of some lovely herps from this reserve, go here.

Back-to-school boots

September 2, 2014 • 4:20 am

It is acceptable to wear cowboy boots after Labor Day, et voilà—a new pair. These have been identified by experts as having been made by the famous bootmaker Carlos Hernandez, who worked for the Martin Boots store in Austin (they have an “MB” logo stamped inside), as well as for some other well known outfits like Lucchese (for whom he designed the famous “State Boots,” and Capitol Boots.

This pair is at least thirty years old, but I bought them completely new on eBay. Not a scratch on the sole.

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Just to let you know that good boots have a history and people who are curious about it, here’s the background that was traced back by the boot aficionado who sold them to me. This is information from the still-living designer:

“Greg Martin was the owner of Martin Boots, but has since passed away. The company was shortlived and yes I did design work for the company. The boots were made by Master Bootmaker Carlos Hernandez, of quite some fame, and his crew of excellent bootmakers. Sadly Carlos has passed away, as well as most of the bootmakers that were quite skilled and produced some very fine boots. They were purchased and renamed Texas Custom Boots, for which I continued to do design for, and managed after Carlos passed away. The company, Texas Custom Boots, has been sold several times. The original bootmakers have all aged and passed away and the company went into decline. Today, the name Texas Custom Boots is owned by Noel Escobar, and is still in operation in Austin, Texas. Not only did I work at Martin Boots, I know that pair, as they have my design on them.”

And from the maker’s daughter:

“My father, Carlos Hernandez Sr. and my brother Carlos Hernandez Jr. were the actual designers and creators of the State Boots that were custom made through Lucchese’s Boot Shop. My father made the patterns and my brother created the designs. Many of the boots were assembled in my home, at 517 W. Martin St., San Antonio, Texas. There were many nights the machines were going all through the night. I witnessed their creation and to this day I own one of the tools used to make them. I am very proud of the legacy left by my father and brother.  Virginia Hernandez Guadiano.”

Lucchese made a set of boots (see the link above for photos) with a theme for each of the 50 states. Only one boot was made for each state, and you can pick up one for about $11,000!

Now, what I don’t know is what kind of hide these boots are made from. It’s clearly reptile, but almost all reptile boots are made from teju lizard, which looks nothing like this. Perhaps some herper can identify the skin. Here’s a close-up:

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Cat with head-mounted laser

September 1, 2014 • 1:20 pm

by Matthew Cobb

We’ve debated the ethics of playing with cats (and other animals) using laser pointers a number of times (e.g. here). This cat’s staff has fitted it up with a head-mounted laser. So at least kitty won’t get his eyes fried. Still not sure it’s the Right Thing to do though.

However, I once had a cat – Spizz, the cat from outer space – who was the smartest cat I have ever known, who would hold one of those long stiff parcel wraps in his mouth, then push it along the kitchen floor, which mind a nice noise, and try and catch it, just like this cat. Except that Spizz figured that out all by himself, and would spend hours messing about. He would also fetch balls of aluminium foil that you flicked across the floor, and bring them back.

A non-prize for the reader who knows why/when we called him Spizz.

 

Spot the tawny frogmouths

September 1, 2014 • 11:20 am

Yes, there are two of them here. From Frans de Waal’s public Facebook photos, via reader Steve. There are two birds here: a remarkable example of camouflage:

Tawny frogmouths

This species (Podargus strigoides), a denizen of Australia and Tasmania, is famous for camouflaging itself and closing its eyes. As Wikipedia notes:

One of the best examples of cryptic plumage and mimicry in Australian birds is seen in the tawny frogmouth who perch low on tree branches during the day camouflaged as part of the tree. Their silvery-grey plumage patterned with white, black, and brown streaks and mottles allows them to freeze into the form of a broken tree branch and become practically invisible in broad daylight.  The tawny frogmouth will often choose a broken part of a tree branch and perch upon it with its head thrust upwards at an acute angle using its very large, broad beak to emphasise the resemblance. Often a pair will sit together and point their heads upwards, only breaking cover if approached closely to take flight or warn off predators. When threatened, adult tawny frogmouths will make an alarm call that signals to chicks to remain silent and immobile ensuring that the natural camouflage provided by the plumage is not broken.

 

A Jehovah’s Witness criticizes me for criticizing their policy on blood transfusions

September 1, 2014 • 9:52 am

In my talk on the incompatibility of science and religion, I gave a “worst-case” scenarios of the harm inflicted by choosing religion over science. I’ve written about this before, so won’t belabor it here, but it involves the denial of medical care to sick or injured children on religious grounds.  In most (48/50) U.S., states, parents get a legal break (even exculpation) if their children are harmed or die because medical care is withheld on religious grounds. Christian Scientists and Pentecostal Christians are the biggest offenders, and if you want to read all about this, read When Prayer Fails: Faith Healing, Children, and the Law by Shawn Francis Peters or  God’s Perfect Child: Living and Dying in the Christian Science Church by Caroline Fraser (the former is more legally oriented, the latter a history of the Christian Science Church which is a great book and a real eye-opener.

But Jehovah’s Witnesses (JWs) are also guilty, for their religion, based on two Bible verses prohibiting “eating blood,” does not allow blood transfusions. While some blood fractions are permitted, like hemoglobin itself or clotting factors, the transfusion of whole blood, plasma, red or white cells, and platelets are all prohibited. Also prohibited is the transfusion of “self-donated” blood, whereby you give blood in advance of an operation, giving you time to make new blood, and then you have a reserve should you need it. But you can’t do that—Bible says no.

As a result, many, many Jehovah’s Witnesses have died from refusing blood. Not only that, but they brainwash their children into refusing blood, too. Below is a cover and a picture taken from a 1994 issue of Awake! magazine: an official publication of the Jehovah’s Witnesses. Every child shown died from refusing blood.

How are they characterized?  As “Youths Who Put God First”! When I showed this picture during my talk, there was an audible shudder in the audience.  The children are seen as martyrs for their faith’s delusions.

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But don’t forget that even those parents who refused blood were once children, too, and most of them were probably brainwashed as well, so to say that they had the “choice” to take a transfusion ignores their own upbringing.

I won’t go into Christian Science, but read Carolyn Fraser’s book if you want to see the children killed in the name of Christian Science. What is curious in these stories—and I’ve read many—is the lack of affect the parents show after having killed their children by refusing medical care (often simple procedures like insulin injections or antibiotics).  It is as if they see their kids in the hands of God, and it’s His decision, not theirs. Most maintain that they were good parents, even though their neglect killed their children. And virtually all of those parents get off legally, or are given a slap on the wrist. (In contrast, if you neglect medical care on nonreligious grounds, there is no protection: you are guilty of child abuse or even manslaughter. This is one of the unconscionable privileges that religion gets in our country.)

At any rate, a Jehovah’s Witness came up to me at the meeting (I am curious why they want to attend an atheist/humanist meeting!) and tried to argue with me. Fortunately, I had another appointment, and couldn’t talk. But later that day I got an email from a JW, which I reproduce here without divulging names or identifying information. Note that techniques of “bloodless surgery” have been developed by doctors who deal with Jehovah’s Witnesses and other people who don’t want blood transfusions, though it’s always better to have the option of full transfusion. At any rate, here’s what I received. I have no idea how this person knew I talked about the JWs and blood transfusion (my emphasis below):

I am one of Jehovah’s Witnesses who takes exception to your opinion regarding blood transfusions.  On [date redacted], our [age redacted] year old daughter was pronounced DOA after a car accident in which  she sustained an aortic tear.  Long story short, she is alive today because she did not receive a blood transfusion. The physician who operated on her is convinced she survived because she did not receive blood. According to  [name redacted] the loss of blood served to lower her blood pressure and  other bodily functions compensating for the loss of blood. It gave him the opportunity to repair the damaged aorta and she survived an operation with an 85% death rate-W/O blood!  Her hemoglobin count at one point while in an induced coma was 2.9.  She survived the very same accident from which Princess Diana died two weeks prior.  Princess Diana according to published reports was transfused right in the ambulance.  Is it possible that the added pressure on the aortic tear made the opening larger and put her body under even more stress?  As a result of this surgery, Dr. [name redacted] was asked to a Bloodless Convention to explain his findings in our daughters case. I don’t consider myself a religious fanatic nor am I easily persuaded.  I like to do objective research and am convinced that the Bible is inspired of God. His mandate re. the taking of blood is due to his knowledge of his creation.  Many doctors and scientist are revisiting their position on bloodless surgery. I would like to suggest you look at our website JW.ORG, if you are not to biased against us on general principle.

Well, even if you believe a transfusion would have killed the daughter, and I am not sure I believe it, there are many more kids who died because they didn’t get transfusions. They are the Children Who Put God First.  All doctors would like to have the option of transfusion, but they can’t use if if the patient (even a child) refuses.

The bit in bold shows the true irrationality of this stand, one that is not a simple academic dispute between science and religion, but costs people their lives. And yet this writer claims that he/she is not a religious fanatic, and makes decisions based on “objective research.” This person is wrong on both counts.

I wish there were some way to eliminate religious exemptions from medical care for children. Yet those exemptions were put in place by our own lawmakers—not because they are JWs or Christian Scientists or faith-healing Pentecostal Christians, but because they give the usual unwarranted American deference to religion. They are our laws, and we must be held to account for them. It’s time to change them. Every child should have the chance to live, and that includes getting medical care based on science rather than ambiguous passages in a fictional Iron Age document.

 

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