Is AI damaging our brain power? Jim Al-Khalili explores Secrets of the Brain

It’s a story spanning hundreds of millions of years – but does new technology mean brain power is in decline and will it lose out to AI?

You describe the human brain as the most complex structure known in the universe. Why?

There’s nothing that comes close in terms of complexity. It’s so intricate, with almost a hundred billion neurons and over a hundred trillion connections. If you were to lay all its axons end-to-end, they’d stretch halfway to the Moon.

In your new series, you explore 600 million years of evolution to uncover how the brain came to exist. What surprised you?

That creatures had rudimentary eyes before they had brains. That early evolution of just a light-sensitive receptor - a cell that can absorb sunlight - triggers chemicals that send signals to other cells to tell that creature how to swim in the ocean, how to move towards or away from the light. That didn’t need a brain.

Vertebrates evolved in the oceans and they had rudimentary brains to help them hunt for food and evade predators. But when creatures started to come out of the oceans, there was another step change in brain growth and complexity. They had to process all the visual information entering their rudimentary eyes. That triggered a growth in their brain power and the brain had to grow.

The other thing to mention is extinction events. In the Permian Mass Extinction, 95 per cent of all life on Earth was wiped out. Luckily for us, 5 per cent of life survived. To survive, it had to face challenges. To figure out solutions, it needed a larger brain.

How much of our brains do we use?

It’s an urban myth that most of the brain isn’t used. We use a very significant fraction.

Why do we know so little about the brain?

I’m a theoretical physicist and people say, “Quantum physics, that’s so difficult.” No, it’s easy. You can explain so many things with one equation. It can tell you what atoms or galaxies can do. With biology and biochemistry, there’s layer upon layer of complexity. The brain has interconnectedness in a way that no other part of the body has.

What would you like to know about the brain?

To understand more about how and why the brain deteriorates with age. One of the big challenges in medicine today is to understand things like dementia. We’re all living longer but our mental faculties and processes deteriorate.

What can we do to look after our brain?

If you don’t use it, you lose it. The brain is like a muscle that has to be maintained. Keeping your mind active is important. Maintaining a large social group of friends and keeping your mind exercised is useful to help stave off things like dementia.

When it comes to intelligence, is brain size important?

The ant’s brain is so tiny it can’t hold the hundred billions of neurons inside. Among different humans however, that won’t have any effect.

Is there anything mysterious about the brain?

Some people might think it’s bleak but I find it beautiful that all of our emotions, our thoughts, memories and feelings, are just electrical signals in the brain.

To me, it’s wondrous – something so simple and logical as an electrical spark going between two neurons. Multiply that trillions of times and you end up with the wonder that makes us human.

How does the human brain compare to AI?

Our brains have trillions and trillions of connections between our neurons. AI doesn’t have that many connections, or the artificial version of them, so can’t have the same complexity of the human brain.

AI can learn how to mimic language, do calculations and spot tumours in images that the human eye can’t recognise. AI can do things a lot better than us. But those are very individual tasks. General intelligence is something that requires much more complexity than AI has at the moment.

In 2018, as president of the British Science Association, you delivered a lecture on the challenges and opportunities that comes with AI. What’s changed since?

We’re only talking seven years ago but people weren’t talking about AI back then. My message was: “AI is coming at us very quickly. We have to be ready for it. We have to engage. What are the bad things about AI? What do we need to be careful about?”

We still don’t know what the future brings. Things are changing very quickly. ChatGPT and large language modules suddenly burst on the scene, and they’re changing the world.

Are you optimistic about our future use of AI?

Some see it as an existential threat that, before you know it, robots will take over the world and we’ll all be turned into paperclips! I’m not a complete doom-monger. We need to be mindful of what we want from AI, and to make sure that it’s there to help us solve problems.

I think that one day AI will become conscious, will be sentient, self-aware. There’s nothing magical about the human brain - once AI is running on a substrate that is complex enough, then consciousness, like a dimmer switch, will gradually come on and become brighter.

At some point, maybe not in our lifetime but probably sometime before the end of this century, AI will become self-aware. It doesn’t mean that AI will be human or like humans. They won’t think like us. They’ll be nothing like us. It means that they have a sense of themselves. They can imagine themselves.

And at that point it becomes dangerous?

This is the big unknown. We want to make sure that in the stages of getting it towards consciousness, we build in certain morals.

Humans have developed traits, empathy and compassion and kindness, possibly through evolution. I don’t want to do something to you that I wouldn’t want you to do to me, because that’s detrimental to me. So we co-operate. But we’ve learned that over millions of years of evolution. AI doesn’t have those millions of years of evolution. So we have to build that into it, the good traits that we want from AI, rather than an AI being a complex psychopath.

Is reliance on AI damaging our brain power?

We’re getting to the stage, not necessarily with AI but with technology as a whole - it’s not just making our lives easier, but making our lives poorer.

If children are having shorter attention spans because they’re used to social media, TikTok or short YouTube videos, they’re losing the ability to concentrate for longer periods of time. There is a concern that technologies are getting to the point where they’re useful but also have a detrimental effect, and may be detrimental to our mental health.

Some of my students prefer to watch a recording (of my lectures). They say, “It’s useful because I can watch five minutes, take some notes, go back and listen to it again.” They’re less practised at focusing and concentrating for long periods of time.

Secrets of the Brain airs Monday 29th September on BBC Two at 9pm. All episodes will be available on BBC iPlayer from 6am. The series is co-produced by The Open University.

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