15 Nature vs. nurture

As visible in the video below, babies have an in-born preference for sweet, they respond neutrally to salty taste, while they have an in-born aversion for sourness and bitterness. Other taste preferences develop through exposure and post-ingestive consequences, that is nurture.

Tastes are often described as having a nutrient-signaling function, eliciting expectations about the intrinsic qualities of the food: its macronutrient composition. Sweetness is for example highly correlated to carbohydrate content and sodium content is highly correlated to saltiness. An umami taste can be related to the protein content of the food, and a fat taste is correlated with energy content. Often, these tastes interact. Umami taste for example is also associated with sodium and fat content in foods, as highly savory foods usually contain a lot of salt and fat next to glutamate as well. Bitter taste is often associated with alkaloids, reflecting poisonous substances, whereas sour taste is associated with acids commonly found in unripe fruits.

It is thought that for this reason, babies have an innate aversion to bitter and sour, and a preference for sweet.