Home  >  CrowdScience  >  If a tree falls in a forest does it make a sound?
CrowdScience
If a tree falls in a forest does it make a sound?
CrowdScience
Apr 2, 2021

If a tree falls in a forest, and no-one is there to hear it, does it make a sound? This is an age-old debate that listener Richard and his family have been arguing about for years. Can CrowdScience settle it once and for all?

Caroline Steel speaks to experts in hearing, biology, philosophy, physics and sound design, which takes her to some unexpected places.

Professor Stefan Bleek is an expert in psychoacoustics who says that sounds only exist in our heads. Dr Eleanor Knox and Dr Bryan Roberts are philosophers that make her question if anything exists outside our own perception. Professor Lilach Hadany wonders if it’s limited to humans and animals - could other plants hear the falling tree too? And Mat Eric Hart is a sound designer who says that sound is subjective – it’s always tangled up with our own interpretations.

Things get truly weird as we delve into the strange implications of quantum physics. If there is such a thing as reality, doesn’t it change when we’re there to observe it? Does the tree even fall if we aren’t there?

Presenter: Caroline Steel Producer: Anand Jagatia

(Image: Fallen Tree. Credit: Getty Images)

More Episodes
Jun 26, 2026
Do animals care about the past?

“What separates humans from animals, is an interest in the past”. That’s a 900-year-old quote from a textbook that Nigerian listener Taiwo came across, and he wrote to CrowdScience to ask if modern science would agree.

Most of us spend time thinking about the past, whether it is nostalgia for a bygone age or just wondering where we put the house keys yesterday. But is that just a human activity or do other animals also ruminate on their history and use it to make decisions? Taiwo wants to know if there is any evidence to show that animals have an interest in the past and if it matters to them.

Presenter Caroline Steel has a history of answering questions like this, so she sets out to find an answer. She meets researchers who have found evidence that animals not only remember past events, but use their memory for planning.

She talks to neuroscientist Dr Freyja Olafsdottir and discovers that some animals, including rats and mice, have the same brain structure for memory as humans.

She meets baby magpies in Professor Nicola Clayton’s laboratory in the UK and finds out about some of the very smart tactics jays use to hide their food from rivals, evidence that they’re using their memory to protect their interests.

She talks to psychologist Dr Gema Martin-Ordas whose research has shown that chimpanzees not only remember past events, but use what they’ve learnt in the future.

And she tests the memory of her own cat Oli, wondering if his ability to remember dinner time suggests that he is interested in the past too.

Ultimately it comes down to questions of consciousness, so as Caroline grapples with the idea that we can’t even be certain that other humans are genuinely conscious, what hope do we have of finding an answer for Taiwo?

Presenter: Caroline Steel

Producer: Jo Glanville

Editor: Ben Motley

(Photo: Cute clever cat with glasses reading a book. The cat lies on a stack of old books on a blue background. Credit:vvvita/Getty Images)


26min 28sec



Jun 5, 2026
Do plants have personalities?

CrowdScience listener George is showing Alex Lathbridge around a small, dark, and extremely hot shed, just outside the city of Accra in Ghana. Inside are row after row of shelves, stacked high with bulging grow-bags. And out of some of them, gorgeous cascades of oyster mushrooms are bursting into bloom.

We’re on George’s mushroom farm, and he’s noticed something interesting. Even though the conditions in his grow-shed are tightly controlled – they have exactly the same food, water, and light as each other – nevertheless, they respond differently. Some are more vigorous than others, some bloom quicker, others last longer, and some are more tolerant when the conditions change. And this got George wondering. Could ‘brainless’ lifeforms like mushrooms, and plants, have different ‘personalities’? Do they experience the world differently, and live their lives differently from each other? Alex Lathbridge is on the case.

He visits the PGRRI, the Plant Genetic Resources Research Centre, for a quick lesson on genetic variation in the plant world. Plants are all different at the genetic level, and it’s those differences which can result in a tastier fruit, or a hardier crop. But would we call traits like these personality?

In the Minimal Intelligence Lab in the University of Murcia in Spain, Paco Calvo thinks that we absolutely should. He studies plant intelligence, and points Alex to a whole host of examples of plants being smart in ways which might surprise you. Each one is an individual, and if we can only slow down enough to appreciate them properly, we’d be able to understand them better too.

Back in Ghana, Alex meets plant physiologist Dr Acheampong Atta-Boateng, in the beautiful grounds of Aburi Botanical Gardens, to meet some of these plants for himself. And he discovers that there’s a whole world of smart, resilient, and resourceful little organisms in the plant world, full of personality, if you know where to look. Who needs a brain!?

Presenter: Alex Lathbridge

Producer: Emily Knight

Editor: Ben Motley

(Photo: Drawing of a face and smiling eyes on a sunflower flower - stock photo- Credit: Jose A. Bernat Bacete via Getty Images)


29min 16sec

If a tree falls in a forest does it make a sound?

--:--
--:--