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Things 119: Journey, Tree Record, Climb and Descent

Game: Journey
If you’re a gamer, you’ve probably heard about Journey. If you’re not a gamer, then you should have heard about it anyway, because it’s quite beautiful and amazing, and only takes 2-3 hours to play through, which means you could visit a friend that has a PS3 and play it in one sitting.

But why would you want to do that?

In this interview, Jenova Chen, the game’s creative director, says:

“Augustine wrote: ‘People will venture out to the height of the mountain to seek for wonder. They will stand and stare at the width of the ocean to be filled with wonder. But they will pass one another in the street and feel nothing. Yet every individual is a miracle. How strange that nobody sees the wonder in one another.’

“There’s this assumption in video games that if you run into a random player over the Internet, it’s going to be a bad experience. You think that they will be an asshole, right? But listen: none of us was born to be an asshole. […] It is the system that made the player cruel, not the player themselves. So if I get the system correct, the players are human and their humanity will be drawn out. I want to bring the human value into a game and change the player’s assumption.”

The reason I say the game is amazing is that it succeeds at this seemingly impossible aim. I’ve played through it a few times now, and each time I’ve had at least one incredibly positive and sustained play experience with a complete stranger.

http://www.youtube.com/watch?v=_mF8KkDiIdk

[Video not working, try this search – metatim, 02/08/15]

Film: The Cabin in the Woods
If you like horror films, you really should watch The Cabin in the Woods. I don’t think it quite succeeds at Joss Whedon’s stated aim (which you shouldn’t look up until after you’ve seen it), but it’s worth it for the wonderfully insane final half hour or so, which, impressively, the trailer largely resists showing any of:

http://www.youtube.com/watch?v=7ENUBUdFswM

[Video not working, try this search – metatim, 02/08/15]

Video: Tree Record / Years
The technology to turn wistful ideas into a reality is in our hands. Look at this device and imagine what you want it to do:

Now check out the video, where it does exactly that:

Read a bit about it here.

Puzzle: Climb and Descent
Tarim recently introduced me to levels 1 and 2 of a puzzle I’d only ever previously heard set at level 3. This week: level 1.

On Day 1, Joss Whedon hikes his way up a mountain, starting at the bottom at midday, and reaching the top (with a few rest stops along the way) 12 hours later, at midnight. He basks in the glory of his achievement for 12 hours, then at midday on Day 2 sets off back down the mountain, reaching the the bottom 12 hours later again, at midnight.

The question: is there a particular time at which he passed through exactly the same altitude on both his Days 1 ascent and Day 2 descent?

Answer: Voice recognition
A long time ago I asked what one could do to improve the chances of having your words understood by one of the many would-be voice-recognition services we find around us today.

After a bunch of googling around, the answers seem to be:

  • Reduce ambient noise where possible
  • Don’t speak too loudly and close to the microphone
  • Leave longer gaps between words than you might in natural speech
  • Speak with the accent the device was tested for

That last point is the one I’m most interested in. The question is, what accent should you use?

It seems the various companies offering this service (Apple/Siri, Google voice search, Xbox Kinect) do have to release different versions for different parts of the English-speaking world (I don’t have a good source for that, but it’s the impression I get from their staged releases, people’s reported experiences, and common sense).

My next plan is to carry out a small personal test in which I try putting on different accents. Results will of course be reported here.

@metatim

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Things 112: Eyes, Guessing Cat, Amigara Fault

This week Things has a very slight Hallowe’en theme.

Puzzle
This is one where you should gather some people around the monitor and see who can do best: guess the cartoon (or CG) character from their eyes (mouse over the eyes to see the character outline that should tell you if you’re right).

And yes, it is pretty difficult – I only got 6, and I watch a lot of animation!

Video
Here’s a video that begs the question: is the cat playing the game, or just acting out of blind instinct?

http://www.youtube.com/watch?v=QrlTijuhVOA

To which the answer is to have a big argument about the definitions being used before concluding that you can’t tell.

Quote
In the wonderfully stylised animation The Secret of Kells, I heard the line “One beetle recognises another” and wondered if it was some kind of proverb. It turns out that it is, and actually – obviously – there are a whole bunch of Irish Proverbs, which in translated form become alternately profound, banal or hilarious, just as I imagine English proverbs must seem if you haven’t grown up with them. Here’s a list of them on Wikiquote, and here are a few of my favourites, for unstated reasons:

“Every beginning is weak.”

“Time is a good story teller.”

“A lamb becomes a sheep with distance…”

“The quiet are guilty”

Comic
The Enigma of Amigara Fault is a horror comic that impressed me with its unconventional approach. It’s 32 pages, and originally in Japanese so you have to read the panels right to left. But if you want a comic that will freak you out for Hallowe’en, it’s worth it. Unless you’re particularly claustrophobic, in which case you should probably steer clear of it entirely.

Answer – Malady X
In Things 111 I asked what the probability of having Malady X is if a randomly administered 99%-accurate test for it comes back positive. As Phil and Thomas noted, you can’t actually answer from this information alone: you also have to know what the probability of a random person actually having Malady X is. A lot of people don’t have an intuition for this fact. I’m going to attempt to explain ways to apprehend that hand-wavingly, mathematically, and visually.

Argument from hand waving and examples:
Imagine the probability of having Malady X is 0% – nobody has it. In this case, it’s certain that getting a positive result means you were simply in the 1% of cases where the test comes back incorrect.
Conversely if the probability of having it is 100% – everybody has it – then you must be in the 99% of cases where it is accurate. In this way, it’s clear the underlying probability influences the chances that the test is correct!

We might worry that these extremes somehow break the puzzle, so let’s imagine less extreme alternatives. Imagine 1,000 people are tested. If 50% (500) really have Malady X, on average we expect the test to come back positive for 99% of them (495) and also for 1% of the 500 that don’t have it (5). In this situation, 495 out of the 500 people for whom the test was positive actually have the disease – 99%.

Alternatively, if 1 person (or 0.1%) out of the 1,000 has the disease, they’re very likely to be correctly diagnosed, and we expect roughly 10 of the other 999 to get a positive result. In this case 1 out of 11 people with a positive result actually have Malady X – fewer than 10%. So clearly the underlying incidence level matters.

Argument from maths:
There are two probabilities at work: the chance the test is correct (99%) and the chance of anyone having Malady X (unknown – let’s call it X%). When you combine probabilities you multiply them, so for example the chance of anyone actually having Malady X AND getting a postive result is 99% times X%.

If someone gets a positive result and that’s all we know, we reason as follows:
A = Probability someone has Malady X and tests positive = X% times 99% times
B = Probability someone does not have Malady X but still tests positive = (100% – X%) times 1%
If you test positive, the chance you actually have it is C = A / (A+B). But if you haven’t studied probability carefully, I’m not sure you could infer this, which is why I like to come up with other ways of getting a feel for the correct answer.

Argument from visualisation:
Since there are two probabilities in question, and we combine probabilities by multiplying, this naturally suggests a visualisation where probability is represented by rectangular area (since area is calculated by multiplying height by breadth).

For example, if we imagine the actual incidence rate of Malady X is 50%, the picture would look like this (click for big):

If the test result is positive, you either have it and the result is correct (big yellow area) or you don’t have it but the test was incorrect (small dark blue area). The chance of you actually having Malady X is equal to the proportion of those combined areas that is yellow. In this case:
Yellow = 99% x 50% = 49.5%
Dark blue = 1% * 50% = 0.5%
Probability you have it = Proportion that is yellow = 49.5% / (49.5% + 0.5%) = 99%.

Alternatively if the incidence rate is, say, 2%, it looks like this:

Here we see the yellow and dark blue areas are very similar, so the chance of you being one or the other is much more even. In fact, it’s:
Yellow = 99% x 2% = 1.98%
Dark blue = 1% x 98% = 0.98%
Probability you have it = Proportion that is yellow = 1.98% / (1.98% + 0.98%) = 67% (ish).

As Peter Donnelly shows in this TED talk, this actually has some severe ramifications, because when the probability of the thing being tested for is extremely low, it becomes overwhelmingly likely that a positive result is false, but people intuitively feel that a 99% accurate test should be correct 99% of the time.

Thomas also noted:

If anyone is interested in playing around with the probabilities (even if you’re not familiar with the maths), I recommend GeNIe:
http://genie.sis.pitt.edu/
It lets you create networks of dependencies, set evidence and work out probabilities in problems just like these.

-Transmission finally ends