Thinking about the iPhone 6

▼ It looks like the introduction of the iPhone 6 is only a few weeks away. And if the rumors are to be believed, it's going to be bigger than the iPhone 5/5S/5C. People talk about 4.7 inches vs 4 inches for the iPhone 5 family, which I'll take as 12 cm vs 10 cm—a 20% increase¹.

That 10 cm for the iPhone 5 is the screen diagonal, which means that the screen is 5 by 8.8 cm. The size of the iPhone 5C is 5.7 by 12.4 cm, so it's 0.7 cm wider and 3.6 cm taller than the screen. If the iPhone 6 also has a screen with a 16-by-9 aspect ratio, that means the screen will be 6 by 10.6 cm. So if nothing else changes, the phone would be 6.7 cm wide and 14.2 cm tall. However, it makes sense that Apple would be able to trim the bezel, especially the "forehead" above the screen—it will be harder to shrink the "chin" now that it houses a fingerprint scanner. So the iPhone 6 is going to be big, but not huge. I currently have a case for my iPhone 5 that's 13.2 by 7.1 cm, and that's entirely workable.

I'm certainly interested in having a bigger phone, as my current iPhone 5 is still very cramped when it comes to reading text and watching video. Some people argue that a big phone is problematic because you can't reach the corners of the screen onehanded. I find that a nonsensical argument. There's no law that says touch targets need to be in the far corners of the screen. In that regard, it's strange that buttons (well, to the degree that iOS still has buttons) tend to be at the top of the screen these days, while earlier they used to be at the bottom, within an easy thumb's reach. However, the now-common left-to-right swipe to get back to the previous screen helps a lot.

But the question is: if the new iPhone has a larger screen, how will the extra space be used? To fit the same amount of text, but in larger type, so it's easier to read, or to fit more text at the same size? There's something to be said for both, so I hope that Apple will make this a user choice. (They already sort of do that by letting you select a text size preference in iOS 7.) A related question is what the pixel dimensions of the iPhone 6 will be. There are basically four choices:

1. 1136 x 640: the same number of pixels as the iPhone 5/5S/5C, 106 pixels/cm (271 pixels/inch)
2. 1364 x 768: the same pixel size as the iPhone 5/5S/5C at 128 pixels/cm (326 pixels/inch)
3. 1280 x 720 HDTV resolution at 120 pixels/cm (305 pixels/inch)
4. 1920 x 1080 HDTV resolution at 180 pixels/cm (457 pixels/inch)

I'm thinking (and hoping) that it's not 1136 x 640. Apple has refused to play the "let's go to insanely high resolutions" game that has been going on on the Android side, but dropping below 300 PPI while some Android phones are pushing 500 would probably be too much of an alleingang, in my opinion. I also doubt that Jony Ive and his team would allow ugly pixels to be visible. The advantage would be that no changes to iOS applications would be required.

1364 x 768 would be an obvious choice, as there's no hit in pixel resolution. Also, 768 is a familiar number from the iPad screen. However, I don't think there's much synergy there as text size and touch targets intended for the iPad would be way too small on an iPhone—the screen of the iPad mini is twice as wide (12 cm) as that of the assumed iPhone 6 (6 cm). Also, how would existing iPhone apps run? Scaling 1136 x 640 to 1364 x 768 would probably not look great, and not scaling means that there's a 0.5 cm border on the sides and 0.9 cm border on the top and bottom of the screen (in portrait orientation). Far from ideal.

I think 1280 x 720 makes the most sense. I'm not sure to what degree Apple values using round numbers, but 1280 x 720 is a widely used HDTV resolution, which can't hurt. At these pixel dimensions, the screen resolution would be still be a hair over 305 PPI, which is the magic "Retina®" resolution. (As far as there is such a thing.) Unupdated iPhone applications could be displayed with borders on all sides, which would be 0.3 cm left and right and 0.6 cm on the top and bottom (portrait mode). That seems fairly workable—the iPhone 5 had almost 0.7 cm borders at the top and bottom when running unupdated apps.

Finally, there's the possibility that Apple decides if a 1280 x 720 HDTV resolution is good, the higher 1920 x 1080 HDTV resolution would be great. I highly doubt they would do this, as such a high resolution provides diminishing returns, but does require a good deal more processing to push more than twice the number of pixels around. Also, the new pixel resolution would be 1.6875 times bigger than the old one, requiring non-integer scaling of applications. Or with small black borders, the scaling factor could be 1.5 times for "retina" apps and 3 x for low resolution applications. That just doesn't seem The Apple Way. Then again, last year Apple decided it was time for 64-bit computing in the mobile space, and nobody saw that coming.

Hopefully, the iPhone 6 comes with 2 GB RAM. The current 1 GB RAM isn't as tight as 128 (!), 256 and 512 MB in various earlier iPhones, but 64-bit code as well as the duplication required to run 32-bit and 64-bit code side by side eat up a good amount of extra RAM and it's good to have some reserve to power future iOSes.

It's high time that 16 GB as the default storage option goes away. On my iPhone 4, 32 GB was pretty spacious, although even four years ago, paying € 100 extra for the upgrade from 16 GB was expensive. But iOS has bloated a lot, and with a few big applications and 16 GB music, I barely have room for a video or two. So I really need a 64 GB iPhone, and I'm not going to pay € 200 extra for that. You can buy a 500 GB SSD for that kind of money these days.

Last but not least, I hope Apple can resist making the iPhone 6 ultra-thin, and leaves room for a decent battery instead. When I got my iPhone 5, I did a bunch of battery tests, and at that point, the battery life was pretty much identical to that of my iPhone 4, which was two years old by then. However, pretty soon I started having issues where the phone would shut down if I tried to do too much at the same time if the battery was below 50%, especially in cold weather. (Taking a photo would typically do it, as that fires up the GPS which in turn causes cellular data traffic.) It took me a while to figure out that five minutes later, I could turn the phone back on. These days, I have to be very careful with the way I use my iPhone in order to make it last through the day on a single charge.

I've been buying new iPhones every two years since 2008, so I could very well buy the iPhone 6 this year. (And it certainly helps that a new Apple Store has opened pretty much within walking distance from my house!) On the other hand, the even years bring unproven redesigns. Two years ago, there was the lightning cable annoyance, and it took Apple a year to get around to releasing new docks. So I could also see myself skipping a year, replace my iPhone 5's battery instead, and see what the iPhone 6S or 6C brings next year.

¹ Update: actually it's 10.2 cm, so going from the iPhone 5 family to a 12 cm iPhone 6 constitutes a 18% increase in size, not 20%. Also see this post.

Permalink - posted 2014-08-21

Obesity and food palatability

▼ I've been doing a lot of reading and Youtube watching about nutrition the past year or so. So I've seen all the scary numbers about the increasing obesity levels in the United States (and elsewhere) numerous times¹, and seen all the speculation about the reason why Western populations started getting so much heavier the past decades.

One popular viewpoint is that it's the carbohydrates and the higher insulin levels that result from consuming carbs. For instance, see Why We Get Fat by Gary Taubes. However, researcher Stephan Guyenet presents a fairly compelling case that this isn't the real cause: The Carbohydrate Hypothesis of Obesity: a Critical Examination.

In a seven-part series of blog posts Guyenet lays down a theory of his own: Food Reward: a Dominant Factor in Obesity, part Ⅰ, part Ⅱ, part Ⅲ, part Ⅳ, part Ⅴ, part Ⅵ, part Ⅷ². Or read this Boing Boing post: Seduced by Food: Obesity and the Human Brain.

It basically boils down to: our food tastes so good that we simply can't stop ourselves from eating too much of it. One study that Guyenet mentions is one where participants are fed a bland tasting liquid through a straw. They can consume as much of it as they want. Lean people take in their normal amount of calories and maintain their weight, but overweight/obese people consume very little and rapidly start losing weight—all the while claiming they're not hungry!

Although more research is required before something as complex as this can be declared settled, I find Guyenet's arguments quite compelling. Few people overeat simple, uninteresting foods. But we find it hard to eat just a little of something that tastes really good. If high palatability of our food is indeed the reason more and more people get overweight and obese, that's pretty good news, because then the solution is simple: eat blander food. Also see this (much shorter) post on Guyenet's blog: Palatability, Satiety and Calorie Intake.

¹ It annoys me to no end that they measure the fraction of the population that crosses a rather arbitrary line; in this case a BMI of 25 for healthy to overweight and 30 for overweight to obese. But the line between a healthy weight and overweight is fairly meaningless, someone with a BMI of 24.9 isn't healthier than someone with a BMI of 25.1 to any measurable degree, and nor is someone with a BMI of 29.9 compared to someone with 30.1. However, the progression from the healthy 18.5 - 25 range to the obese > 30 range obviously isn't good.

² If you see strange characters here: I used Unicode roman numerals rather than the regular I and V characters.

Permalink - posted 2014-07-29