Dr Hannah Critchlow awarded 2026 Rosalind Franklin Lecture Medal

Humanists UK hosted the 2026 Rosalind Franklin Lecture, titled ‘The Science of Fate’, delivered by neuroscientist, broadcaster, and author Dr Hannah Critchlow. Chaired by journalist and broadcaster Samira Ahmed, the lecture explored how our biology, our brains, and our experiences shape who we are – and what that might mean for ideas of free will, identity, and human connection.

Hannah began by asking a deceptively simple question: what makes us who we are? From our habits and beliefs to our relationships and emotional lives, she said, neuroscience is increasingly showing how many of our complex behaviours are deeply biologically ingrained. Reflecting on her early experience working as a nursing assistant on adolescent psychiatric wards, she described how this first sparked her desire to understand the brain better – both to improve treatment, and to answer deeper questions about what creates our individual life stories.

Hannah staged what was a Humanists UK first: a live electroencephalogram (EEG) demonstration. With an audience volunteer wired up on stage, the room watched the electrical activity of the brain in real time – the ‘electrical dance’ of billions of neurons, measured as waves of different frequencies. As our volunteer moved and tried to meditate, Hannah used the display to explain how neuroscientists have studied the brain’s activity for over a century, and how different patterns of activity relate to movement, calm reflection, creativity, and sleep.

Brain waves and the ‘same wavelength’

Hannah then turned from the individual brain to groups of brains working together. When people collaborate well, she said, their brain activity can begin to synchronise – literally putting them on the ‘same wavelength’. Eye contact, singing, and exercising together can all help increase this brain-to-brain synchrony, which in turn supports bonding, learning, and cooperation.

She linked this to a larger theme running through the lecture: that humans are not solitary minds, but profoundly social thinkers. Rather than being like the sea squirt – a creature that settles in one place and digests its own nervous system once it no longer needs to move or interact – human beings have evolved to explore, communicate, and learn from one another. That drive to exchange ideas, Hannah argued, has been central to our success as a species.

What biology can shape

Hannah explored how far genetics and brain structure can influence human behaviour. Traits such as schizophrenia, intelligence, sociability, and even ideology, she said, all appear to have some degree of heritability, though environment remains crucial too. She highlighted research suggesting that extroverts and introverts may differ partly in the structure of the orbital frontal cortex, and argued that both cognitive styles play important roles in society: introverts helping sustain close, supportive communities, and extroverts helping carry ideas between groups.

She also discussed research suggesting there may be biological influences on political orientation, pointing to studies linking ideological tendencies to different patterns of brain activity and structure. But far from reducing people to biology, Hannah stressed that diversity of minds is one of humanity’s greatest strengths. No two brains are the same, she said, and this immense variation in experience, wiring, and temperament underpins both our individuality and our collective success.

Trauma, plasticity, and change

One of the most striking parts of the lecture focused on epigenetics – the study of how experiences can leave chemical marks on DNA that affect how genes are expressed. Hannah described the landmark 2014 mouse experiment by Kerry Ressler, in which mice were conditioned to fear the smell of cherries, and their descendants appeared to inherit that fear response. Similar mechanisms may exist in humans, she said, with research suggesting trauma can leave epigenetic traces across generations.

But Hannah was equally clear that biology is not destiny. Drawing on her own PhD research into synaptic plasticity, she emphasised the brain’s lifelong capacity to change. New experiences, learning, and supportive environments can all help create new neural pathways, even if our biology places limits on how easily change comes. This, she suggested, should encourage greater compassion: some people may face much steeper biological challenges than others, and understanding this can help us respond with more humanity rather than blame.

A ‘great evolutionary transition’

In the closing part of the lecture, Hannah suggested humanity may now be undergoing a ‘massive evolutionary transition’. Technology, she argued, is linking billions of minds together into an increasingly connected ‘brain pool’, where ideas can be shared, debated, and refined in real time. From planes and Zoom to social media and artificial intelligence, our tools are accelerating a new kind of collective intelligence.

For Hannah, this was ultimately a hopeful vision. If our brains are shaped by genes, ancestors, and experience, they are also shaped through connection with others. The more we understand the diversity of minds and the conditions that help them flourish, the better equipped we are to build a more compassionate and collaborative society.

After a lively Q&A – which ranged from ageing and memory loss to social media, online connection, and neurodiversity – Samira Ahmed presented Hannah with the 2026 Rosalind Franklin Lecture Medal. The medal was awarded for her ‘fearless exploration of the thorny concept of free will’, and for showing how understanding the constraints on our choices may help us shape a better future.