Cambridge neuroscientist Hannah Critchlow: Why two heads are better than one to beat falling IQ

It’s not just your imagination - globally our intelligence scores have taken a collective dip. And, thanks to the isolation caused by the pandemic, they have suffered an even bigger impact.

Neuroscientist Hannah Critchlow is coming to the Cambridge Festival, supported by the Cambridge Independent, to discuss her latest book Joined Up Thinking which reveals this startling research that shows we are becoming less clever as a species - but she has some evidence-based ways to combat this.

The first is that we may need to go back to the office, or at least work together face to face online, to reap the benefits of collective intelligence. The second method to improve decision making and problem solving would be to throw men off committees and put women in charge.

She explains: “There have been some recent studies looking at our IQ levels which show they have been falling for the first time across Europe, and also in other parts of the world, including Japan. It was previously thought that our IQ levels actually have been increasing over the last century or so. But for those people that were born from the 1970s onwards, our IQ levels have unfortunately started to plateau out and so our individual intelligence levels actually seem to be in jeopardy, which is not great news.”

Leaving our offices to work alone from home during the pandemic appears to have made the situation worse.

“There are lots of ideas about why IQs are getting lower, whether it’s the junk that we eat, our sedentary lifestyles, or whether environmental toxins might be asphyxiating our brains in some ways. But what I really wanted to look at was the neuroscience underpinning how our brains work together and at how collective intelligence arises. Because, what the pandemic really showed us is that although we can work in isolation, it is possible, it's just not preferable. There has been study after study that showed us even before the pandemic, that we need each other for our physical and emotional health, but also our intelligence as well. And those studies that showed that our IQ levels actually started to decrease as people started shielding and they were going into lockdown measures, and then started to go back to the original IQ levels, as people reentered society. “

Hannah, who is an internationally-acclaimed neuroscientist, broadcaster and author based in the city, where she is science outreach fellow at the University of Cambridge’s Magdalene College, has written Joined Up Thinking, to look at ways we can overcome this.

“We need each other’s brains to keep our brains healthy,” she says.

“You can see that actually when we work together as a group, that’s when ideas can kind of hop from mind to mind. And ideas can evolve so we start to innovate and problem solve, and collaborate and look to the future. At the same time, I also wanted to write this book because we're being faced as a species with a number of existential challenges, whether it’s geopolitical instability, or climate change, or the threat of the next pandemic, for example.”

She discusses new discoveries in neuroscience that underpin how our collective intelligence arises, and how we can innovate together and how you can start to bring diverse minds together and allow them to communicate and build consensus and learn from each other to solves the world’s biggest problems.

For example, she explains that if two people are working together on a problem their brain waves start to synchronise and become more in step the more successfully those people are working together. The degree of brain synchronicity predicts how well they will solve the challenge. She reveals there are “little tricks” that can be used to increase this synchronicity. These have been proven to include singing together, looking into each others’ eyes and doing “mass exercise” together such as running marathons.

“It’s fascinating the behaviours that we exhibit which seem to help bond individual members together, so that we can start to access that cognitive capacity that’s available to us not just within individuals within, but also within our neighbours’ mind or our friends’ or colleagues’ mind.

Our brainwaves synchronise because when we work together we begin to take information in about the world in the same way.

Hannah says: “The brain is taking on board like something like 11 billion bytes of data per second, coming in through all of your senses, and your brain takes those little bits of data and then conjures up this idea that actually there’s a continuous reel of reality, like a video that’s been created by your brain stitching together these little stills of information that are coming in. And what brain synchronisation means is that people are starting to take in the little snapshots of information at the same timestamps.

“So they’re literally taking in the same bits of information from the outside world. So that’s going to help them align their viewpoints, but also this brain synchronicity seems to help boost learning between the group members because they’re seeing the world in literally the same timeframe. And it seems to help boost consensus building goals as well.”

In order for a group to reap the positive effects of working together, they need to avoid dominance by individuals.

Hannah says research has shown women do best at turn taking and making collective decisions.

“The number one factor that will predict how well a group will perform and their collective intelligence score, is gender ratio. So the higher the number of females within a group, the more successful that group will be. It’s not because collective intelligence is written out of the Y chromosome, it’s that females have been culturally indoctrinated to do more turn taking and listening. And that ability to tend to listen rather than dominate conversations actually helps individual members of the group contribute their individual intelligence.

“The group as a whole has a higher amount of cognitive capacity on offer because we’re better able to tap into the individual members intelligence that’s there. So then you’re better able to problem solve.”

She has a suggestion for ineffective committees or councils.

“You could kick off all of the guys from the team or the council and replace them with females. That’s one way that you could probably increase group success...”

Other suggestions include letting the most junior team member speak first to avoid “dominance dynamics” where everyone echoes the leader. Or committees could ask members to write down suggestions anonymously.

“That actually generates twice the number of ideas compared with people verbally speaking up, and the ideas are generally rated to be as high in value.”

But what of the lone genius, such as Sir Isaac Newton, who came up with his theory of gravity when he was isolated during the plague? Hannah suggests this is not the whole picture.

“Those people have often been surrounded, in a place such as Cambridge, by many different minds discussing all kind of topics.”

It is only from this fertile ground that a genius can then go off alone to make discoveries.

• Joined Up Thinking: The Science of Collective Thinking and its Power to Change Our Lives, is on March 29 at 8pm in Babbage Lecture Theatre (through the Pembroke archway), New Museums Site Downing Street, CB2 3RS. Book free tickets at: festival.cam.ac.uk.