Every time Apple releases a new iPhone there's a dramatic spike in the number of Google searches for the phrase "iPhone slow". Does this give credence to the conspiracy theory that Apple intentionally slows down iPhones to encourage you to buy a new one?

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If you ever felt like your iPhone got slower around the time Apple released the next edition of the device, you're definitely not alone.

Some digging into Google Trends by Harvard University PhD student Laura Trucco has shown that searches for "iPhone slow" have peaked consistently at the time Apple releases a new iPhone.

The same pattern has occurred since the 2008 release of the iPhone 3G, but what do the spikes mean? Could it show that Apple slows down older iPhones to nudge owners onto newer ones, helping it announce record breaking sales in the weeks after it releases a new iPhone? Or do people just think their old devices have become slower because they're presented with a newer, faster device?

According to Harvard economics professor Sendhil Mullainathan, Apple has incentives not to cripple existing devices in order to prod consumers into upgrading — known as "planned obsolescence" — even though it has, in principle, the means and motive to do so.

The simple reason Apple wouldn't cripple its devices can be found in Android; iPhone owners would switch to a product that has a longer life if they constantly find their devices effectively becoming bricked with each new release. Besides that, there would be legal risks for Apple in pursuing that strategy.

Still, because Apple sells the device and makes the operating system, Mullainathan argues that Apple does in principle have the means and motive to be able to slow older devices. Google on the other hand lacks such an incentive because it doesn't make money on hardware, while Samsung, which does have the same motive as Apple, lacks the means to slow down performance.

Arguing the case for the conspiracy theory, Mullainathan looked for spikes in searches for "Samsung Galaxy slow" and found no noticeable correlation between the phrase and hardware release dates. In other words, that the spikes only happen for iOS devices would support the conspiracy theory that Apple does hobble its devices to encourage upgrades.

Also, the spikes in "iPhone slow" searches occur when it releases a new phone and not when it announces it — it should peak when the new phone is announce if it's really just a perceived slowdown in performance due to knowledge of a new device.

However, the conspiracy theory is undermined by differences in how Apple and Google distribute new versions of iOS and Android to devices.

As Mullainathan notes, one explanation for the Samsung-iPhone difference is Android fragmentation. Currently only 18 percent of devices run KitKat, for example, whereas Apple has shifted nearly 90 percent of its users to iOS 7. Performance degradation caused by an OS update would therefore be more pronounced with the iPhone.

In the end, the correlation between the search for slow iPhones and Apple's hardware release cycle is a cautionary tale in interpreting meaning from data.

"The important distinction is of intent. In the benign explanation, a slowdown of old phones is not a specific goal, but merely a side effect of optimizing the operating system for newer hardware. Data on search frequency would not allow us to infer intent. No matter how suggestive, this data alone doesn't allow you to determine conclusively whether my phone is actually slower and, if so, why," writes Mullainathan.

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