Why do we like the foods we like? Written by Rosie McCallum, Festival Communications Assistant Marmite, you either love it or you hate it. So says one of the most famous marketing campaigns in the UK, however why we have such a strong attraction or aversion to this gloopy brown liquid is a whole other matter entirely. A recent talk by Dr Lucy Chambers and Professor Jeff Brunstrom at the British Science Festival explored the reasons behind how and why humans have developed such unique taste palettes for the diversity of food there is available today. Dr Chambers, an Honorary Senior Research Fellow in the School of Psychology at the University of Sussex, discussed how food preferences are gatekeepers of good nutrition and, therefore, how there is a strong need to raise children who like the taste of healthy food. The nature/nurture debate features heavily in these issues, and many studies have been conducted to find out how much of a role genes play in affecting our food preferences. In one study, solutions of basic tastes were dropped into the mouths of newborn babies, producing hilarious results in the photographs of their reactions- sweet tastes eliciting cute smiles whilst bitter-tasting drops giving faces worthy of extreme-gurning competitions. This showed that preferences are inbuilt at birth, with an evolutionary perspective explaining the preference for sweet being associated with gaining energy, whilst bitter tastes have negative associations with toxic substances we should avoid. Another study in sets of twins showed there is a substantial genetic element to liking certain food groups, however the abundance of variation is explained by life experiences, showing nurture is just as important as nature. Infants’ food preferences can even be affected before they are born. As the foetus’s sense of taste and smell is fully developed in the last trimester of pregnancy, the mother’s diet can make the foetus more familiar with certain flavours. After they are born, there are three main ways infants learn about food: familiarisation, observational learning and associative learning. For picky eaters, giving tiny bits of food and even getting the child to feel, smell and touch undesirable food can increase their acceptance of it. Other influences of surroundings, such as gardening, cooking, and even reading picture books can help in children’s acceptance of foods, however one of the most effective ways is by having role models. Children will copy and be influenced by certain people in their lives and so language can play a very important role in influencing children’s eating habits. Professor Brunstrom, a Professor of Experimental Psychology at the University of Bristol looked further back than human infancy, to when humans only collected food by hunter-gatherer methods more than 1 million years ago, to see if the nuts and bolts of human behaviour can help make us eat healthier. We have evolved to forage efficiently, as the longer we spend looking for food, the more vulnerable we are to predators and the more energy we lose (which could be being spent on reproduction). This is why we are more likely to choose higher-energy food sources (and also explains why you’re more likely to opt for a mars bar than a banana). The fact that we find food delicious allows us to want to eat and therefore fuels and nourishes ourselves. Humans show a preference for energy density foods, and sensory cues play important roles in this. Insects are considered a delicacy in many countries around the world, particularly in parts of South East Asia, however many Europeans are disgusted by the thought of putting crickets in their mouths, despite their nutritional benefits. Therefore, culture and the way we are brought up plays a huge role in affecting our preferences. Learning also can impact food preferences. Experiments on animals trying a flavour where nutrients are injected into their stomach compared to a flavour where just water is injected into their stomach, results in the animal developing a preference for the flavour given with the nutrients added. What we can take away from all these findings are even more questions for how we can healthily consume food in a modern world. How we will promote a preference for healthy foods, and if these mechanisms are compromised by a modern dietary environment, will need to be answered by the next generation of scientists, who this festival has surely inspired.