Showing posts with label science. Show all posts
Showing posts with label science. Show all posts

Thursday, May 27, 2010

My favorite optical illusions

A post on the other blog inspired me to post some of my favorite optical illusions. Here...

1) Same Color Illusion.

copyright: Edward H Adelson and web.mit.edu


Look at the image above. Which of the squares A and B do you think is the darker shade of gray? A? Well, as it turns out in every such optical illusion, the answer is - None. They are the same shade. Exactly the same shade. :) The brain interprets the intensity based on the context. Ever wondered why sunspots are dark? As in, it's not as if those regions aren't bright and hot  themselves, so why do they appear dark? It's because they are embedded in much hotter and brighter regions of the Sun. This is exactly what is happening here. A seems darker because it has light squares around it. B seems light because it is surrounded by dark squares. I feel that the strength of this particular image is in the fuzzy boundary of the cylinder's shadow.  This means that B's shade merges into the light square's shade seamlessly fooling the brain into expecting that B must actually be the same shade as the light squares, only that they are slightly darker due to the shadow. But same as A? No way! well, it is. :) Perhaps the image below will help in visualizing it.
copyright: Edward H. Adelson and web.mit.edu

2) Blue or Green?

Copyright Akiyoshi Kitaoka 

You know what's coming. But you can't believe it, can you? The spirals that are clearly blue and green are actually neither blue nor green, but a combination (RGB=0,255,150). i.e. they are EXACTLY the same color. unbelievable? I know. This one actually makes one forget the first illusion entirely. I mean, it was difficult to believe that one, but surely this is simply impossible? Well, copy it to paint/photoshop and see the RGB values. Or, just crop some pixels from the blue and green spirals without their pink/orange context and juxtapose them. Or, if you don't really have to do it yourself to believe it, just head on to this article at the badastronomy blog and see for yourself. This really is stunning.

3) Ok, this one is fun. Look at  this one. Which direction is the (apparently nude, but I digress... ) spinning? Clockwise? Counter-clockwise?


No idea about copyright, but I found it here. Anyway, once you know your initial answer, look again. Perhaps looking at the shadow of the feet will do it the first time. The spinning direction flips instantly! It is actually much easier to flip the interpretation in your mind after you succeed in seeing it once. I can do it within 5-10 seconds now, and yet it is such a rush everytime it happens! :) Specially when I focus on her face. Suddenly the hair jumps from front to the back. :) I think this is essentially the same thing as flipping the 3-D interpretation of the Necker Cube in your mind. But, somehow this spinning girl makes it much more fun! :)

4) And now, the killer. Hollow mask illusion. I don't need to say anything as they say it all in the video.



Incredible, no? I have always wanted to have one of these masks at home. Specially this next one, with einstein. But it is definitely not worth 60 dollars....



Do you have any favorite illusions? Do share in comments.

Monday, May 03, 2010

Smiling lips and singing hearts

I recently finished reading "Musicophilia" by Oliver Sacks, and I thought that a condition mentioned in one of the chapters is worth posting about here. It is called "Williams Syndrome".

In WS, certain anatomical features are underdeveloped or faulty. This includes certain facial features (you'll see them having unusually wide-eyed expressions), certain heart and artery muscles etc. More importantly, perhaps, specific parts of the brain are highly underdeveloped, while others are either overdeveloped or at least unusually dominate because the others parts aren't developed properly. The parts that are underdeveloped are the ones that have an important role in numerical/logical thinking and spatial sense. The parts that are often overdeveloped or seem to dominate are the ones that have roles in linguistic skills, social skills and apparently emotional impact of music (thats where "musicophilia" comes in).

So, people with WS are highly gregarious... extremely friendly and social with everyone.. they almost completely lack any social inhibitions, so that they seem to be completely comfortable in the presence of almost anyone, regardless of whether they are familiar with them. Moreover, they actually seem to enjoy such interactions and seem to be unusually clued-in to the emotional cues in other peoples behavior/facial expressions etc.

Their linguistic skills are almost always highly developed, making them highly articulate. This, along with their friendly/social nature means that you'll always find them having long, extended conversations with almost anyone. On the other hand, they find it extremely difficult to do even the most simple math problems. You could be talking on phone with someone who has WS and probably won't realize that anything is unusual (other than the person being unusually charming and friendly) until you ask him/her to tell you what 3+5 is. Chances are, they'll fumble through the problem and will probably only guess an answer, which will probably be wrong anyway. Lack of a normally developed spatial sense means that they find it hard to work with even simple geometric shapes (like the toys that toddlers play with) and can hardly draw even simple things like a triangle or a circle. In short, as Sacks says, they are almost anti-autistic in their characteristics.

Sacks talks about some people having WS that he has met. There are really interesting stories here. e.g. when one little girl's mom told her not to talk to strangers, she replied with "but there are no strangers, there are only friends"

Another girl he met (she was about 7-8 years of age) was so clued in to other people's facial features and was so completely uninhibited in front of strangers that she surprised him by sensing his slight diffidence and said promptly something like  "don't be shy! I'll make some muffins for you". This, from a girl, who had never met Sacks before. Sacks had gone to her home to see her and was probably only about as inhibited as any of us would be when we go to someone's house for the first time (Well, some of us are probably more inhibited than others... my diffidence would probably be easy to sense for almost anyone. :P )

Anyway, so she went ahead and got some muffins for him. In some time, Sacks asked her (perhaps after covering the plate, though I am not sure) to guess how many muffins there were in the plate. She guessed, with some effort, "3". Then he asked her to go ahead and count them. She tried and counted them one by one and came up with 8. There were actually 13.

Another girl, a 15 year old, had an IQ of 49 - quite typical of people with WS. So, her average mental level was of around a 7-8 year old kid i.e. about a student of 2nd standard. But that doesn't mean, as I said before, that you'd be able to tell that by just talking to her. It's not as if they seem "retarted" in any sense. math/logic/spatial sense don't work properly, but they are exceptional in linguistics. They are highly articulate, which makes things difficult when they are in new company (difficult for them, sure, but also difficult for these new people). After all, none of us expect someone to be that articulate, YET having mental problems

Take this 15 year old girl with IQ 49. They asked her to tell them about what an elephant is. And her response, quoted below, is amazing in its detail. It is almost as if she is telling a story rather than answering a simple question :

"And what an elephant is, it is one of the animals. And what the elephant does, it lives in the jungle. It can also live in the zoo. And what it has, it has long gray ears, fan ears, ears that can blow in the wind. It has a long trunk that can pick up grass, or pick up hay… If they are in a bad mood it can be terrible…If the elephant gets mad it could stomp; it could charge. Sometimes elephants can charge. They have big long tusks. They can damage a car… It could be dangerous. When they're in a pinch, when they're in a bad mood it can be terrible. You don't want an elephant as a pet. You want a cat or a dog or a bird…"

So, to put it mildly, she knows something about what an elephant is. The amazing part is, after this, when they asked her to draw an elephant, this is what she drew -

copyright: Ursula Bellugi, the Salk Institute

(The labels were put by someone else to help others see what she might've been trying to make. She only made the figure.) Clearly, she knows about the fan like ears and tusks etc, but she can't draw any of those details at all.

The connection with music is pretty interesting actually.. all of them are strongly sensitive and emotionally attached to music. Now, this doesn't necessarily mean that all of them are very good at playing music or singing (though a lot of them are). This is, as Sacks points out, quite unlike musical savants. Musical savants are almost finished articles. They will dazzle the whole world by their exceptional musical talents, yet, they might not necessarily derive as much pleasure out of music as a normal person around them. WS patients, however, invariably feel very strongly towards music.

This strong emotional connection to music, in combination with their completely uninhibited nature means that you'll find them merrily singing or whistling or playing music or swaying to music a lot of times. if you are walking on the road and they suddenly hear you even humming something they'll just smile broadly and will likely start singing along with joy. Some parents/guardians of a lot of WS patients decided to get a lot of together for a camp. Sacks describes what he saw at one of these camps and it sounds amazing. 15-20 people with WS - most, but not all, very young - sit together and talk to each other as if everyone is part of a close family. Talk about everything under the sun. And then, suddenly, someone starts humming and everyone joins in.. Some play their instruments, while others jump in and harmonize. Some just let their bodies follow the rhythm. I'd say that it is pretty sad to know about this, but it's really difficult to feel that way after reading about their joy in these camps or, indeed, their connection to music.

Tuesday, April 06, 2010

A tiny platform above the abyss.


Clive Wearing contracted a virus in 1985, a virus that is pretty innocuous in most people (one of the many that give you sore throats for a few days) but changed his life forever. The virus infected his brain resulting in his getting one of the most severe cases of anterograde "Memento" amnesia known. He hasn't formed a new memory in last 25 years. Moreover, the virus also caused severe retrograde amnesia, meaning that a lot of his memories prior to 1985 also went away. A lot of times he seems to be living in 1960s, if you can call chunks of 7-30 seconds of life "living". That is the extent of his short term memory. Think about it. 7 seconds. What would it be like if everything in your mind gets erased in 7 seconds? It is not just a matter of not remembering what happened in his life at any time during last 25 years. As tragic as that is, one could still sort of imagine living the same day again and again if one has, say, half an hour window of memory... something like Memento. You wake up, you don't know where you are, you see your tattoos, you remember your wife was killed, you make notes, you make a plan that you might forget later but at least you can MAKE it. What can you do with 7 seconds? 

He lives at a country residence with other similar "patients" with some caretakers. The caretakers encouraged him to write journals. Perhaps they thought it will give him something to do. Perhaps it would help in objectively following his progress. So, here is what you do with a 7-30 second memory. This is how his journal looks -

9:00 am - woke up after a long sleep.
9:15 am - just woke up
9:30 am - Really, overwhelmingly awake now
10:00am - just waking up, despite my other claims

That is about the extent of his thoughts most of the time. Seriously, how do you even complete a thought in 7 seconds? And if you can't, what does ANYTHING mean anymore? What does even "being you" mean?

Still, he has some memories of 40 years ago. Its not as if he has forgotten what the world around him means. And his procedural memory is intact. Which means that things that are part of a "habit" or "muscle memory", things that have become "ingrained" are accessible even if no "event memory" exists of anything since 1985. So, he talks. And he talks about the same things again and again. Because these are the only things that are accessible to him through his procedural memory. He'll talk about astronomy, Queen Victoria, electricity, etymology of words. But perhaps not a lot other than that. He'll throw in a joke. The same joke after every few minutes.It helps him to see that people around him can get the joke. It reassures him that he still has a connection with the world. He keeps talking from the same ingrained "scripts" to make a tiny platform of reality around his present because beyond that platform there is an abyss... nothingness stretching away... Thats what his wife calls it - "A tiny platform above the abyss". 

And he plays music. He hasn't forgotten how to do that. Procedural memory. He even improvises while playing. He just doesn't remember that he had just played some music after he finishes. Or that he has made the same "improvisation" again and again perhaps. 

And, he remembers, and still deeply loves, his wife Deborah. He remembers her even though the retrograde amnesia has taken almost all other memories from  much before the time when he first met her. Oliver Sacks writes in his book "Musicophilia", where I found about Clive's case - 

"... somehow he always recognized Deborah as his wife when she visited and felt moored by her presence, lost without her. He would rush to the door when he heard her voice, and embrace her with passionate, desperate fervor. Having no idea how long she had been away - since anything not in his immediate field of perception and attention would be lost, forgotten, within seconds - he seemed to feel that she, too, had been lost in the abyss of time, and so her "return" from the abyss seemed nothing short of miraculous." 

Deborah writes, "Clive was constantly surrounded by strangers in a strange place, with no knowledge of where he was or what had happened to him. To catch sight of me was always a massive relief - to know that he was not alone, that I still cared, that I loved him, that I was there. Clive was terrified all the time. But I was his life, I was his lifeline. Every time he saw me, he would run to me, fall on me, sobbing, clinging."

How would it feel to be embraces with passionate, desperate fervor many times a day by someone who is honestly, sincerely, deeply in love with you. How would it feel to see in someone eyes that you were missed by with the intensity of a decades long separation.. how would it feel to see that every day.. every hour... every time he sees you. You are the only person on his tiny platform. You ARE his tiny platform. For 25 years.