Helen Wong, 15, Dallam School, UK
Smartphones can do almost anything these days, so it's not surprising that people have lost the ability to perform tasks manually. The autocorrect function makes daily tasks such as texting and googling easier. But it also means people don't need to remember how to spell or use punctuation properly.
Smartphones are "smart" as they can tailor information for users. Their user-friendliness, such as giving shortened news excerpts, means many people are unable or unwilling to read chunks of longer text.
We no longer need maps. People use GPS when they travel to a new place.
The invention of emojis means we don't need to use words as often. Our word bank has been reduced to pictures and short messages. As a result, words like "cool" and "nice" have become virtually all that we know.
All these examples show how our over-reliance on our phones has reduced our ability to complete basic tasks ourselves.
Worse still, people no longer live in the moment. Whenever something amazing happens, people get out their phones and take a picture. Others miss it, because they're too busy checking their phones, looking at Facebook and texting their friends. They are unaware of the world around them. Many car accidents happen because people can't take their eyes away from their phone for a few seconds to look at the road.
More and more, people's values and identities are defined by their phones. They feel lost without them. They feel insecure and naked if they don't have them to hand. We've all seen this scene: in a restaurant, you see a group of friends sitting at a table but all looking at their phones.
Smartphones have made us forget how to talk. They make us anxious when we talk to others. Our phones are our comfort zones and our identities are hidden behind the masks of our phones.
The widespread selfie culture also means that people are becoming increasingly self-absorbed. People see selfies as a way to gain popularity. People measure their success by how many "likes" a photo gets.
In this technological era, there is no denying that life has become more complex. But as human beings, we have become dumber as our smartphones have simplified life for us.
Cedric Li, 15, Sha Tin College
It only takes a change in perspective for you to realise just how smart smartphones really make you. My grandmother got a new iPhone for her birthday, and my job was to teach her how to send pictures on WhatsApp. After I had done this, she called me a very smart boy, and it was then that I realised how smart I really was.
I am able to control such an intricate piece of technology in my hands. The skill and ability needed to use smartphones is a testament to our intelligence. How can we say that smartphones are making us dumber? (Though I did feel pretty dumb when Grandma filled my WhatsApp with random cat pictures.)
Smartphones are one of the greatest learning resources out there right now. They give us the ability to quickly find answers to our questions. Smartphones are maps, encyclopedias, newsstands. With so much information of all sorts, smartphones can't possibly make us dumb. Before their invention, we had to pick through the thousands of dusty old books in libraries to find information. Now we can easily find it using just our fingertips.
According to a New York Times article, the idea that using technology can somehow shorten our attention span and make us "dumber" is merely a myth. Such a change in our mental functions would "happen over evolutionary time" - not the time it takes you to learn how to use a smartphone.
But the study did show that smartphones create a negative impact on the willingness of humans to concentrate. Even if this is true, there is still a big difference between lower concentration levels and saying that smartphones are making us dumber.
So relax. Smartphones aren't making you dumber. If you really are worried, you could always pop onto Jaden Smith's Twitter page because his words actually make you wiser.