Remember when people were complaining that the iPhone 4 had signal problems, and the late Apple CEO Steve Jobs said we were holding it wrong?
As ridiculous as that sounded, he may have been right.
A report by professor Gert Frølund Pedersen of Aalborg University in Denmark clearly shows that holding the iPhone 6S in one particular hand while on a phone call can mean you get worse cell signal reception than if you hold it in the other.
This chart from Pederson shows signal strength for phone calls when you hold various types of phones in each hand. There's a huge difference between hands with the 6S, and particularly the 6S Plus. The difference is much less with other types of phones, including the iPhone SE.
Pedersen notes in his report that the difference isn't as wide when you're using data services for things like surfing the web, using apps, browsing social media, or streaming music and video. However, the difference is still significant.
Why?
The difference has to do with something called "body loss," which is essentially the interference caused by our bodies and the way the antennas were designed. According to Pedersen, a smartphone's signal strength performance "depends strongly on the antenna in the phone and on the way the user is holding the phone to the head during a call or in the hand during browsing mode."
It turns out that the iPhone 6S and iPhone 6S Plus do "not take body loss in different usage positions into account" while other smartphones do a better job at it, according to Pedersen.
We've contacted Apple for comment on these findings, but haven't heard back yet.
So, in a way, we were indeed holding the iPhone 4 - and now the iPhone 6S and 6S Plus - the wrong way if we were getting weak signal strength. But that's because Apple apparently did not design those iPhones to handle "body loss" very well at all.
Apple
Apple redesigned the antenna stripes on the iPhone 7 and 7 Plus, but we don't yet know whether or not they'll improve the iPhone's comparatively poor signal strength performance.
If you live in an area where signal strength is usually high, this might not affect you as much. However, if signal strength is spotty where you live and work, then you might consider buying a phone with that can handle your body's pesky interference. Or, always hold your iPhone in your left hand when you make a call.