Why Do We Do That?

It’s a familiar problem with any shared household - there’s always someone who doesn’t do their fair share. Studies have shown that when people with different thresholds live together, the person with the lower tolerance for mess cleans up more, quickly leading to resentment and conflict. So why do some people clean up more than others? What needs to happen for everyone to pull their weight? Evolutionary science has some answers. Ella Al-Shamahi speaks to Dr Nichola Raihani, Professor of Evolution and Behaviour from University College London, to find out about free riders, cheaters and public goods, and how evolutionary scientists view cooperation challenges. Great British Bake Off star Michael Chakraverty shares his own anecdotes of untidy flatmates and failed attempts to enhance cooperation.

Make-up has a long history - from the surprising use of lipstick in ancient Greece to today's Tiktok trends - and though fashions may have changed, some things, like red lips, cheeks, and defined eyes, keep cropping up. So in this episode, Ella Al-Shamahi investigates if there is any biological basis to make-up? Joined by Journalist and BBC Radio 1 presenter Katie Thistleton, and psychologist Professor Richard Russell, Ella discovers fascinating research on how make-up can change the way we perceive faces and ponders on a slightly strange theory about make-up and orgasm.

You might think sitting is a recent technological advancement, but both squat and sit-down toilets have been around for millennia. Today Westerners have embraced the sit-down toilet, whereas billions in Asia, the Middle East, Africa, and even parts of Europe use toilets that are designed specifically for squatting. But which is better for us - sitting or squatting? Ella Al-Shamahi speaks to gastroenterologist Dr Rohan Modi who has been investigating the best way to do your business, and gets personal with comedian Eshaan Akba.

Are you at one with midnight, or up before sunrise? In this episode, Ella Al-Shamahi investigates when we naturally feel tired and awake, known as our chronotype. Our chronotype depends on our lifestyle, our environment, where we live, and is also influenced by our genes. In this episode, Ella Al-Shamahi uncovers fascinating research which suggests our chronotype can be traced back over 100,000 years ago, to when our early modern human ancestors interbred with Neanderthals. She speaks to geneticist Tony Capra how DNA from our Neanderthal ancestors may be influencing our present-day sleeping habits and shares her revelations with professional early riser and BBC Radio 1 Early Breakfast presenter Arielle Free.