Why are some smells so nasty and others so pleasant? Rutherford and Fry inhale the science of scent in this stinker of an episode. Our sleuths kick off with a guided tour of the airborne molecules and chemical receptors that power the sense of smell. Armed with a stack of pungent mini-flasks, Professor Matthew Cobb from the University of Manchester shows Hannah and Adam just how sensitive olfaction can be, and how our experience of some odours depends on our individual genetic make-up. Dr Ann-Sophie Barwich from Indiana University reveals how most everyday smells are complex combinations of hundreds of odorants, and how the poo-scented molecule of indole turns up in some extremely surprising places.With the help of a flavoured jellybean and some nose clips, Hannah experiences how smell is crucial to flavour, adding complexity and detail to the crude dimensions of taste. Speaking of food, listener Brychan Davies is curious about garlic and asparagus: why do they make us whiff? Professor Barry Smith from the Centre for the Study of the Senses reveals it's down to sulphur-containing compounds, and tells the story of how a cunning scientist managed to figure out the puzzle of asparagus-scented urine. Finally, another listener Lorena Busto Hurtado wants to know whether a person’s natural odour influences how much we like them. Barry Smith says yes - we may sniff each other out a bit like dogs - and cognitive neuroscientist Dr Rachel Herz points to evidence that bodily bouquet can even influence sexual attraction! Producer: Ilan Goodman Contributors: Professor Matthew Cobb, Professor Barry Smith, Dr Ann-Sophie Barwich, Dr Rachel Herz

Holley Gerth, a life coach and author, explores the nuances of introversion and extroversion, addressing common misconceptions and encouraging self-acceptance. She discusses traits, strengths, and the societal pressures faced by both personality types. Ann-Sophie Barwich, a cognitive scientist, dives into the fascinating world of smell—how it impacts perception and evokes memories. The conversation highlights the unique nature of our olfactory senses and their influence on behavior, offering insights into why certain smells resonate with us.

Ann-Sophie Barwich, a philosopher and neuroscientist specializing in olfaction, explains why smell deserves more attention in our understanding of consciousness. She challenges the primacy of vision by highlighting the complexities of the olfactory experience and its interplay with taste. Barwich delves into how molecular structures influence scent perception, and how our context can drastically alter our interpretation of odors. She also explores the fascinating cognitive processes behind wine tasting and discusses how olfactory cues play a significant role in decision-making, particularly in romantic contexts.