Tag Archives: Human evolution

‘Me, Human’ at the Science Museum: Your 500 million year old brain

Scientists from Birkbeck and collaborating institutions are in the ‘Who Am I?’ gallery all summer to present the ‘Me, Human’ project. Dr Gillian Forrester reflects on what led her to research this topic. 

Me, Human is a live scientific experiment which will investigate how traits from our 500 million year-old vertebrate brain still underpin some of our most important and human unique behaviours – like recognising faces and generating speech. At Live Science this summer you’ll use your eyes, ears and hands to find out more about how your ancient brain actually works. We are a multidisciplinary team of scientists at all levels of our careers from undergraduate students in psychology and biological anthropology to senior academics at leading London universities. We all have a passion to communicate science and demonstrate how we, as humans, share a common evolutionary history with other animals – and to reveal our extraordinary connection to the natural world.

We are all individuals, but we acknowledge that we might have inherited grandma’s nose or dad’s extrovert personality. Have you ever thought about what physical and psychological traits we humans – as a species – have inherited from our ancestors?

As a child, I was fascinated by our closest living relatives – the great apes. I wondered – what do gorillas and chimps think? How similar is their experience of life to mine? I scratched this itch by watching documentaries, reading books and eventually taking degrees in San Diego and Oxford. It was during my studies that I started to learn about brains and how they control behaviour. What struck me as truly incredible was that there are parts of the human brain that come from when humans and fish shared a common ancestor – over 500 million years ago!

As humans, we are able to think and act in ways unlike any other animal on the planet. Because of these unique capabilities, it is easy to forget that modern human abilities have their origins in a shared evolutionary history.

Although we are bipedal and comparatively hairless, we are indeed great apes. In fact, we are not even on the fringes of the great ape family tree – we are genetically closer to chimpanzees than chimpanzees are to gorillas. As such, we share many brain and behaviour traits with our great ape cousins. But our similarities to other animals date back much farther than our split with an ancestor common to both humans and great apes (approximately six million years ago). Some brain and behaviour traits date back over 500 million years –present in early vertebrates and remain preserved in modern humans.

It is our similarities and differences to other species that allow us to better understand how we came to be modern humans.

One of our oldest inherited traits is the ‘divided brain’. While our left and right halves of the brain (hemispheres) appear physically similar, they are in charge of different behaviours. Because the left and right hemispheres control physical behaviour on the opposite side of the body, we can see these dominances revealed in the everyday actions of animals (including humans).

Animal studies have highlighted that fishes, amphibians, reptiles, and mammals also possess left and right hemispheres that differentially control certain behaviours. The divided behaviours of these animals provide a window into our ancestral past, telling the story of our shared evolutionary history with early vertebrates.

Studies suggest that the right hemisphere emerged with a specialisation for recognising the threat in the environment and controlling escape behaviours and the left hemisphere emerged as dominant for producing motor action sequences for feeding (as pictured above). The divided brain allows for any organism to obtain nourishment while keeping alert for predators. We can think of the brain as acting like an ‘eat and not be eaten’ parallel processor.

Considering the consistency in brain side across different animal species, it seems likely that there has been a preservation of these characteristics through evolutionary time. Effectively, we have lugged our useful brain and behavioural traits with us throughout our evolutionary journey.

But why should we care?

Little is known about how these old brain traits support modern human behaviours, like the way we navigate social environments, kiss, embrace, nurture babies and take a selfie! – inhibiting a better understanding of how, when and why our human unique capabilities emerged and also how they still develop during human infancy and childhood.

By taking part in Me, Human at Live Science you will learn about cutting-edge research and engage with fun psychology experiments.  This project challenges you to use your eyes, ears and hands to find out more about how ancient brain traits still control some of your most human unique behaviours. Work with scientists to explore how you use a divided brain to experience the world around you. We invite Science Museum visitors to solve puzzle boards, test your grip strength, hold and manipulate objects, recognise faces and react to different sounds. Watch your brain in action, using portable brain-imaging, as you take part in activities that will help us to better understand human brains and behaviours.

The Me, Human team at the Science Museum.

Come and join me and the Me, Human project team on this journey of exploration to find out what it is to be human and how we are connected to all animals in the natural world. Open until Monday 30 September 2019.

Dr Gillian Forrester

  • Director of the Me, Human Project
  • Reader in Psychology
  • Senior Fellow of the Higher Education Academy
  • Deputy Head of Department, Psychological Sciences, Birkbeck, University of London

Visit the exhibition at the Science Museum, London. Follow the Me, Human team on Twitter. #mehuman #livescience. 


Science Week: Piecing together the jigsaw of climate change and human evolution

This post was contributed by Guy Collender, of Birkbeck’s Department of External Relations.

Dr Phil Hopley, of Birkbeck's Department of Earth and Planetary Sciences

Dr Phil Hopley exhibited replica skulls of our ancestors during Science Week. Photo: Harish Patel

I knew an unusual presentation was in store as soon as I saw six skulls menacingly positioned at the front of the lecture theatre. The exhibits – all different shapes and sizes – immediately caught the audience’s attention, and our questions about their origins were answered in the fascinating hour that followed.

Dr Phil Hopley began Birkbeck’s series of Science Week lectures with a talk on 16 April about the links between climate change and human evolution. He used the skulls – five replicas of our ancestors and one gorilla skull – to illustrate how evolution is all about the changing dimensions of the head as it has become rounder and larger to accommodate a bigger brain over millions of years. In comparison, the gorilla’s skull includes ferocious canines and space for huge powerful jaws – it certainly sent a shiver up my spine being only a few feet away from my seat.

A family tree dating back millions of years
Dr Hopley, of Birkbeck’s Department of Earth and Planetary Sciences, explained how the last common ancestor of chimpanzees and modern humans was on this planet about six of seven million years ago. Both branches of the family tree then developed separately, with chimpanzees on the one hand, and about 20 species of hominins – the ancestors of modern humans – walking on two legs on the other. As the hominins evolved, they became characterised by their tool use, larger brains, language and art, eventually developing into Homo sapiens – our own species. But our ancestral line has not been straightforward, and Dr Hopley highlighted the complexity. He said: “Homo sapiens is the only human species alive today, but for most of human evolution there have been a number of co-existing human species.”

As Dr Hopley explained, hominin fossils have mainly been found in two areas – the Rift Valley in East Africa (dating back five million years), and caves in Southern Africa (dating back 2.5 million years). Yet, hardly surprising, given the awesome amount of time involved, it is very rare to find a whole hominin specimen. What is clear is that the human fossil record is very incomplete, both geographically and temporally, and solving the mystery is a bit like piecing together a jigsaw.

Climate change: from forest to grassland
The question of why our ancestors evolved to become bipedal was then addressed, and this was where Dr Hopley referred to his work studying fossils from caves in South Africa. The study of carbon and oxygen isotypes and climate modelling has shown that the savannah in Africa developed eight million years ago due to the reduction in carbon dioxide and reduction in rainfall. As the grasslands replaced the forests, our ancestors evolved to walk on two feet as they needed to cover large distances to search for food, which wasn’t necessary when they were still living in the forest. Although it’s difficult to build up a comprehensive understanding of how climate change drives evolution, Dr Hopley did present a general conclusion. He said: “Human evolution did occur because of climate change in the broad sense as forests were replaced by savannah.”

I’ve never been to a lecture with skulls on display before and I’ll certainly never forget this one. It was a powerful way to remind us that our common ancestors adapted to the African bush and started walking when the forests began to recede.